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Background: The effect of swimming on bone health remains unclear, namely due to discrepant findings between studies in humans and animal models. Objective: The aim of this systematic review and meta-analysis is to identify the available evidence on the effects of swimming on bone mass, geometry and microarchitecture at the lumbar spine, femur and tibia in both humans and rodent animal models. Methods: The study followed PRISMA guidelines and was registered at PROSPERO (CRD4202236347 and CRD42022363714 for human and animal studies). Two different systematic literature searches were conducted in PubMed, Scopus and Web of Science, retrieving 36 and 16 reports for humans and animal models, respectively. Results: In humans, areal bone mineral density (aBMD) was similar between swimmers and non-athletic controls at the lumbar spine, hip and femoral neck. Swimmers' tibia diaphysis showed a higher cross-sectional area but lower cortical thickness. Inconsistent findings at the femoral neck cortical thickness were found. Due to the small number of studies, trabecular microarchitecture in human swimmers was not assessed. In rodent models, aBMD was found to be lower at the tibia, but similar at the femur. Inconsistent findings in femur diaphysis cross-sectional area were observed. No differences in femur and tibia trabecular microarchitecture were found. Conclusion: Swimming seems to affect bone health differently according to anatomical region. Studies in both humans and rodent models suggest that tibia cortical bone is negatively affected by swimming. There was no evidence of a negative effect of swimming on other bone regions, both in humans and animal models. [ABSTRACT FROM AUTHOR]

Background: Running economy is defined as the energy demand at submaximal running speed, a key determinant of overall running performance. Strength training can improve running economy, although the magnitude of its effect may depend on factors such as the strength training method and the speed at which running economy is assessed. Aim: To compare the effect of different strength training methods (e.g., high loads, plyometric, combined methods) on the running economy in middle- and long-distance runners, over different running speeds, through a systematic review with meta-analysis. Methods: A systematic search was conducted across several electronic databases including Web of Science, PubMed, SPORTDiscus, and SCOPUS. Using different keywords and Boolean operators for the search, all articles indexed up to November 2022 were considered for inclusion. In addition, the PICOS criteria were applied: Population: middle- and long-distance runners, without restriction on sex or training/competitive level; Intervention: application of a strength training method for ≥ 3 weeks (i.e., high loads (≥ 80% of one repetition maximum); submaximal loads [40–79% of one repetition maximum); plyometric; isometric; combined methods (i.e., two or more methods); Comparator: control group that performed endurance running training but did not receive strength training or received it with low loads (< 40% of one repetition maximum); Outcome: running economy, measured before and after a strength training intervention programme; Study design: randomized and non-randomized controlled studies. Certainty of evidence was assessed with the GRADE approach. A three-level random-effects meta-analysis and moderator analysis were performed using R software (version 4.2.1). Results: The certainty of the evidence was found to be moderate for high load training, submaximal load training, plyometric training and isometric training methods and low for combined methods. The studies included 195 moderately trained, 272 well trained, and 185 highly trained athletes. The strength training programmes were between 6 and 24 weeks' duration, with one to four sessions executed per week. The high load and combined methods induced small (ES = − 0.266, p = 0.039) and moderate (ES = − 0.426, p = 0.018) improvements in running economy at speeds from 8.64 to 17.85 km/h and 10.00 to 14.45 km/h, respectively. Plyometric training improved running economy at speeds ≤ 12.00 km/h (small effect, ES = − 0.307, p = 0.028, β1 = 0.470, p = 0.017). Compared to control groups, no improvement in running economy (assessed speed: 10.00 to 15.28 and 9.75 to 16.00 km/h, respectively) was noted after either submaximal or isometric strength training (all, p > 0.131). The moderator analyses showed that running speed (β1 = − 0.117, p = 0.027) and VO2max (β1 = − 0.040, p = 0.020) modulated the effect of high load strength training on running economy (i.e., greater improvements at higher speeds and higher VO2max). Conclusions: Compared to a control condition, strength training with high loads, plyometric training, and a combination of strength training methods may improve running economy in middle- and long-distance runners. Other methods such as submaximal load training and isometric strength training seem less effective to improve running economy in this population. Of note, the data derived from this systematic review suggest that although both high load training and plyometric training may improve running economy, plyometric training might be effective at lower speeds (i.e., ≤ 12.00 km/h) and high load strength training might be particularly effective in improving running economy (i) in athletes with a high VO2max, and (ii) at high running speeds. Protocol Registration: The original protocol was registered (https://osf.io/gyeku) at the Open Science Framework. [ABSTRACT FROM AUTHOR]

Background: Assessing certainty of evidence is a key element of any systematic review. The aim of this meta-epidemiology study was to understand the frequency and ways with which certainty of evidence is assessed in contemporary systematic reviews published in high-impact sports science journals. Methods: We searched PubMed and relevant journal web sites from 1 August 2016 to 11 October 2022 for systematic reviews published in the top-ten highest-impact journals within the 2020 Journal Citation Report for the Sports Sciences category. Pairs of independent reviewers screened items using a priori established criteria. Results: Of 1250 eligible documents, 258 (20.6%) assessed the certainty of evidence, defined as using two or more distinct domains to provide an overall rating of the trustworthiness of findings across studies. Nine methods were cited for assessing certainty, with the most common being the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach (61.6%). The proportion of systematic reviews assessing certainty of evidence appeared to increase over the 6-year timeframe analyzed. Across all reviews analyzed, a large majority addressed the domains of risk of bias, imprecision, and inconsistency of the results. Other certainty domains including indirectness/applicability were less commonly assessed. Discussion: Only one in five recent contemporary systematic reviews in the field of exercise and sports science assessed certainty of evidence. Organizational and institutional education on methods for assessing evidence may help further increase uptake of these methods and improve both the quality and clinical impact of systematic reviews in the field. [ABSTRACT FROM AUTHOR]

Publication bias refers to a systematic deviation from the truth in the results of a meta-analysis due to the higher likelihood for published studies to be included in meta-analyses than unpublished studies. Publication bias can lead to misleading recommendations for decision and policy making. In this education review, we introduce, explain, and provide solutions to the pervasive misuses and misinterpretations of publication bias that afflict evidence syntheses in sport and exercise medicine, with a focus on the commonly used funnel-plot based methods. Publication bias is more routinely assessed by visually inspecting funnel plot asymmetry, although it has been consistently deemed unreliable, leading to the development of statistical tests to assess publication bias. However, most statistical tests of publication bias (i) cannot rule out alternative explanations for funnel plot asymmetry (e.g., between-study heterogeneity, choice of metric, chance) and (ii) are grossly underpowered, even when using an arbitrary minimum threshold of ten or more studies. We performed a cross-sectional meta-research investigation of how publication bias was assessed in systematic reviews with meta-analyses published in the top two sport and exercise medicine journals throughout 2021. This analysis highlights that publication bias is frequently misused and misinterpreted, even in top tier journals. Because of conceptual and methodological problems when assessing and interpreting publication bias, preventive strategies (e.g., pre-registration, registered reports, disclosing protocol deviations, and reporting all study findings regardless of direction or magnitude) offer the best and most efficient solution to mitigate the misuse and misinterpretation of publication bias. Because true publication bias is very difficult to determine, we recommend that future publications use the term "risk of publication bias". [ABSTRACT FROM AUTHOR]

It has often been reported that mental exertion, presumably leading to mental fatigue, can negatively affect exercise performance; however, recent findings have questioned the strength of the effect. To further complicate this issue, an overlooked problem might be the presence of publication bias in studies using underpowered designs, which is known to inflate false positive report probability and effect size estimates. Altogether, the presence of bias is likely to reduce the evidential value of the published literature on this topic, although it is unknown to what extent. The purpose of the current work was to assess the evidential value of studies published to date on the effect of mental exertion on exercise performance by assessing the presence of publication bias and the observed statistical power achieved by these studies. A traditional meta-analysis revealed a Cohen's dz effect size of − 0.54, 95% CI [− 0.68, − 0.40], p <.001. However, when we applied methods for estimating and correcting for publication bias (based on funnel plot asymmetry and observed p-values), we found that the bias-corrected effect size became negligible with most of publication-bias methods and decreased to − 0.36 in the more optimistic of all the scenarios. A robust Bayesian meta-analysis found strong evidence in favor of publication bias, BFpb > 1000, and inconclusive evidence in favor of the effect, adjusted dz = 0.01, 95% CrI [− 0.46, 0.37], BF10 = 0.90. Furthermore, the median observed statistical power assuming the unadjusted meta-analytic effect size (i.e., − 0.54) as the true effect size was 39% (min = 19%, max = 96%), indicating that, on average, these studies only had a 39% chance of observing a significant result if the true effect was Cohen's dz = − 0.54. If the more optimistic adjusted effect size (− 0.36) was assumed as the true effect, the median statistical power was just 20%. We conclude that the current literature is a useful case study for illustrating the dangers of conducting underpowered studies to detect the effect size of interest. [ABSTRACT FROM AUTHOR]

Background: The reactive strength index (RSI) is meaningfully associated with independent markers of athletic (e.g., linear sprint speed) and neuromuscular performance [e.g., stretch–shortening cycle (SSC)]. Plyometric jump training (PJT) is particularly suitable to improve the RSI due to exercises performed in the SSC. However, no literature review has attempted to meta-analyse the large number of studies regarding the potential effects of PJT on the RSI in healthy individuals across the lifespan. Objective: The aim of this systematic review with meta-analysis was to examine the effects of PJT on the RSI of healthy individuals across the lifespan compared with active/specific-active controls. Methods: Three electronic databases (PubMed, Scopus, Web of Science) were searched up to May 2022. According to the PICOS approach, the eligibility criteria were: (1) healthy participants, (2) PJT interventions of ≥ 3 weeks, (3) active (e.g., athletes involved in standard training) and specific-active (e.g., individuals using heavy resistance training) control group(s), (4) a measure of jump-based RSI pre-post training, and (5) controlled studies with multi-groups in randomised and non-randomised designs. The Physiotherapy Evidence Database (PEDro) scale was used to assess the risk of bias. The random-effects model was used to compute the meta-analyses, reporting Hedges' g effect sizes (ES) with 95% confidence intervals (95% CIs). Statistical significance was set at p ≤ 0.05. Subgroup analyses were performed (chronological age; PJT duration, frequency, number of sessions, total number of jumps; randomization). A meta-regression was conducted to verify if PJT frequency, duration, and total number of sessions predicted the effects of PJT on the RSI. Certainty or confidence in the body of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Potential adverse health effects derived from PJT were researched and reported. Results: Sixty-one articles were meta-analysed, with a median PEDro score of 6.0, a low risk of bias and good methodological quality, comprising 2576 participants with an age range of 8.1–73.1 years (males, ~ 78%; aged under 18 years, ~ 60%); 42 studies included participants with a sport background (e.g., soccer, runners). The PJT duration ranged from 4 to 96 weeks, with one to three weekly exercise sessions. The RSI testing protocols involved the use of contact mats (n = 42) and force platforms (n = 19). Most studies reported RSI as mm/ms (n = 25 studies) from drop jump analysis (n = 47 studies). In general, PJT groups improved RSI compared to controls: ES = 0.54, 95% CI 0.46–0.62, p < 0.001. Training-induced RSI changes were greater (p = 0.023) for adults [i.e., age ≥ 18 years (group mean)] compared with youth. PJT was more effective with a duration of > 7 weeks versus ≤ 7 weeks, > 14 total PJT sessions versus ≤ 14 sessions, and three weekly sessions versus < three sessions (p = 0.027–0.060). Similar RSI improvements were noted after ≤ 1080 versus > 1080 total jumps, and for non-randomised versus randomised studies. Heterogeneity (I2) was low (0.0–22.2%) in nine analyses and moderate in three analyses (29.1–58.1%). According to the meta-regression, none of the analysed training variables explained the effects of PJT on RSI (p = 0.714–0.984, R2 = 0.0). The certainty of the evidence was moderate for the main analysis, and low-to-moderate across the moderator analyses. Most studies did not report soreness, pain, injury or related adverse effects related to PJT. Conclusions: The effects of PJT on the RSI were greater compared with active/specific-active controls, including traditional sport-specific training as well as alternative training interventions (e.g., high-load slow-speed resistance training). This conclusion is derived from 61 articles with low risk of bias (good methodological quality), low heterogeneity, and moderate certainty of evidence, comprising 2576 participants. PJT-related improvements on RSI were greater for adults versus youths, after > 7 training weeks versus ≤ 7 weeks, with > 14 total PJT versus ≤ 14 sessions, and with three versus < three weekly sessions. [ABSTRACT FROM AUTHOR]

Background: Heat is associated with physiological strain and endurance performance (EP) impairments. Studies have investigated the impact of caffeine intake upon EP and core temperature (CT) in the heat, but results are conflicting. There is a need to systematically determine the impact of pre-exercise caffeine intake in the heat. Objective: To use a meta-analytical approach to determine the effect of pre-exercise caffeine intake on EP and CT in the heat. Design: Systematic review with meta-analysis. Data Sources: Four databases and cross-referencing. Data Analysis: Weighted mean effect summaries using robust variance random-effects models for EP and CT, as well as robust variance meta-regressions to explore confounders. Study Selection: Placebo-controlled, randomized studies in adults (≥ 18 years old) with caffeine intake at least 30 min before endurance exercise ≥ 30 min, performed in ambient conditions ≥ 27 °C. Results: Respectively six and 12 studies examined caffeine's impact on EP and CT, representing 52 and 205 endurance-trained individuals. On average, 6 mg/kg body mass of caffeine were taken 1 h before exercises of ~ 70 min conducted at 34 °C and 47% relative humidity. Caffeine supplementation non-significantly improved EP by 2.1 ± 0.8% (95% CI − 0.7 to 4.8) and significantly increased the rate of change in CT by 0.10 ± 0.03 °C/h (95% CI 0.02 to 0.19), compared with the ingestion of a placebo. Conclusion: Caffeine ingestion of 6 mg/kg body mass ~ 1 h before exercise in the heat may provide a worthwhile improvement in EP, is unlikely to be deleterious to EP, and trivially increases the rate of change in CT. [ABSTRACT FROM AUTHOR]

Background: The video-based temporal occlusion paradigm has been consistently used in visual anticipation sport research.This meta-analysis investigated the magnitude to which video-based temporal occlusion training could improve anticipation skill with transfer to representative laboratory and field tasks.As there are considerably fewer anticipation training than performance studies, the meta-analysis included 12 intervention studies with 25 effect sizes where video simulation and/or field-based tests were used. The Downs and Black checklist adapted for sports science research was used to assess methodological quality of the included studies. Decision time and accuracy of anticipation were the outcome measures because both are relevant to sports skills. The changes in these measures between experimental and control groups from baseline to the transfer test context were used to calculate the magnitude of the training effect.Findings revealed a significant training effect, including a large meta-analytic effect size, and no difference in training benefit across video and field-based transfer tests. Publication bias analyses were inconclusive, likely due to the small number of available studies.These findings are evidence that the temporal occlusion paradigm is an effective method to improve visual anticipation skill across representative perceptual and perceptual-motor transfer tests. The theoretical implication based upon the two-stage model of visual anticipation is that temporal occlusion training can improve use of early information for body positioning by the performer, which could in turn lead to improved execution of the skill goal.Objective: The video-based temporal occlusion paradigm has been consistently used in visual anticipation sport research.This meta-analysis investigated the magnitude to which video-based temporal occlusion training could improve anticipation skill with transfer to representative laboratory and field tasks.As there are considerably fewer anticipation training than performance studies, the meta-analysis included 12 intervention studies with 25 effect sizes where video simulation and/or field-based tests were used. The Downs and Black checklist adapted for sports science research was used to assess methodological quality of the included studies. Decision time and accuracy of anticipation were the outcome measures because both are relevant to sports skills. The changes in these measures between experimental and control groups from baseline to the transfer test context were used to calculate the magnitude of the training effect.Findings revealed a significant training effect, including a large meta-analytic effect size, and no difference in training benefit across video and field-based transfer tests. Publication bias analyses were inconclusive, likely due to the small number of available studies.These findings are evidence that the temporal occlusion paradigm is an effective method to improve visual anticipation skill across representative perceptual and perceptual-motor transfer tests. The theoretical implication based upon the two-stage model of visual anticipation is that temporal occlusion training can improve use of early information for body positioning by the performer, which could in turn lead to improved execution of the skill goal.Methods: The video-based temporal occlusion paradigm has been consistently used in visual anticipation sport research.This meta-analysis investigated the magnitude to which video-based temporal occlusion training could improve anticipation skill with transfer to representative laboratory and field tasks.As there are considerably fewer anticipation training than performance studies, the meta-analysis included 12 intervention studies with 25 effect sizes where video simulation and/or field-based tests were used. The Downs and Black checklist adapted for sports science research was used to assess methodological quality of the included studies. Decision time and accuracy of anticipation were the outcome measures because both are relevant to sports skills. The changes in these measures between experimental and control groups from baseline to the transfer test context were used to calculate the magnitude of the training effect.Findings revealed a significant training effect, including a large meta-analytic effect size, and no difference in training benefit across video and field-based transfer tests. Publication bias analyses were inconclusive, likely due to the small number of available studies.These findings are evidence that the temporal occlusion paradigm is an effective method to improve visual anticipation skill across representative perceptual and perceptual-motor transfer tests. The theoretical implication based upon the two-stage model of visual anticipation is that temporal occlusion training can improve use of early information for body positioning by the performer, which could in turn lead to improved execution of the skill goal.Results: The video-based temporal occlusion paradigm has been consistently used in visual anticipation sport research.This meta-analysis investigated the magnitude to which video-based temporal occlusion training could improve anticipation skill with transfer to representative laboratory and field tasks.As there are considerably fewer anticipation training than performance studies, the meta-analysis included 12 intervention studies with 25 effect sizes where video simulation and/or field-based tests were used. The Downs and Black checklist adapted for sports science research was used to assess methodological quality of the included studies. Decision time and accuracy of anticipation were the outcome measures because both are relevant to sports skills. The changes in these measures between experimental and control groups from baseline to the transfer test context were used to calculate the magnitude of the training effect.Findings revealed a significant training effect, including a large meta-analytic effect size, and no difference in training benefit across video and field-based transfer tests. Publication bias analyses were inconclusive, likely due to the small number of available studies.These findings are evidence that the temporal occlusion paradigm is an effective method to improve visual anticipation skill across representative perceptual and perceptual-motor transfer tests. The theoretical implication based upon the two-stage model of visual anticipation is that temporal occlusion training can improve use of early information for body positioning by the performer, which could in turn lead to improved execution of the skill goal.Conclusions: The video-based temporal occlusion paradigm has been consistently used in visual anticipation sport research.This meta-analysis investigated the magnitude to which video-based temporal occlusion training could improve anticipation skill with transfer to representative laboratory and field tasks.As there are considerably fewer anticipation training than performance studies, the meta-analysis included 12 intervention studies with 25 effect sizes where video simulation and/or field-based tests were used. The Downs and Black checklist adapted for sports science research was used to assess methodological quality of the included studies. Decision time and accuracy of anticipation were the outcome measures because both are relevant to sports skills. The changes in these measures between experimental and control groups from baseline to the transfer test context were used to calculate the magnitude of the training effect.Findings revealed a significant training effect, including a large meta-analytic effect size, and no difference in training benefit across video and field-based transfer tests. Publication bias analyses were inconclusive, likely due to the small number of available studies.These findings are evidence that the temporal occlusion paradigm is an effective method to improve visual anticipation skill across representative perceptual and perceptual-motor transfer tests. The theoretical implication based upon the two-stage model of visual anticipation is that temporal occlusion training can improve use of early information for body positioning by the performer, which could in turn lead to improved execution of the skill goal. [ABSTRACT FROM AUTHOR]

Objective: The aim was to quantify the proportion of the literature on caffeine supplementation that reports habitual caffeine consumption, and determine the influence of habitual consumption on the acute exercise response to caffeine supplementation, using a systematic review and meta-analytic approach. Methods: Three databases were searched, and articles screened according to inclusion/exclusion criteria. Three-level meta-analyses and meta-regression models were used to investigate the influence of habitual caffeine consumption on caffeine's overall ergogenic effect and within different exercise types (endurance, power, strength), in men and women, and in trained and untrained individuals. Sub-analyses were performed according to the following: acute relative dose (< 3, 3–6, > 6 mg/kg body mass [BM]); whether the acute caffeine dose provided was lower or higher than the mean daily caffeine dose; and the caffeine withdrawal period prior to the intervention (< 24, 24–48, > 48 h). Results: Sixty caffeine studies included sufficient information on habitual consumption to be included in the meta-analysis. A positive overall effect of caffeine was shown in comparison to placebo (standard mean difference [SMD] = 0.25, 95% confidence interval [CI] 0.20–0.30; p < 0.001) with no influence of relative habitual caffeine consumption (p = 0.59). Subgroup analyses showed a significant ergogenic effect when the caffeine dose was < 3 mg/kg BM (SMD = 0.26, 95% CI 0.12–0.40; p = 0.003) and 3–6 mg/kg BM (SMD = 0.26, 95% CI 0.21–0.32; p < 0.0001), but not > 6 mg/kg BM (SMD = 0.11, 95% CI − 0.07 to 0.30; p = 0.23); when the dose was both higher (SMD = 0.26, 95% CI 0.20–0.31; p < 0.001) and lower (SMD = 0.21, 95% CI 0.06–0.36; p = 0.006) than the habitual caffeine dose; and when withdrawal was < 24 h, 24–48 h, and > 48 h. Caffeine was effective for endurance, power, and strength exercise, with no influence (all p ≥ 0.23) of relative habitual caffeine consumption within exercise types. Habitual caffeine consumption did not modify the ergogenic effect of caffeine in male, female, trained or untrained individuals. Conclusion: Habitual caffeine consumption does not appear to influence the acute ergogenic effect of caffeine. [ABSTRACT FROM AUTHOR]

Background: Proper design of resistance training (RT) variables is a key factor to reach the maximum potential of neuromuscular adaptations. Among those variables, the use of RT performed to failure (RTF) may lead to a different magnitude of acute fatigue compared with RT not performed to failure (RTNF). The fatigue response could interfere with acute adaptive changes, in turn regulating long-term adaptations. Considering that the level of fatigue affects long-term adaptations, it is important to determine how fatigue is affected by RTF versus RTNF. Objective: The aim of this systematic review and meta-analysis was to compare the effects of RTF versus RTNF on acute fatigue. Methods: The search was conducted in January 2021 in seven databases. Only studies with a crossover design that investigated the acute biomechanical properties (vertical jump height, velocity of movement, power output, or isometric strength), metabolic response (lactate or ammonia concentration), muscle damage (creatine kinase activity), and rating of perceived exertion (RPE) were selected. The data (mean ± standard deviation and sample size) were extracted from the included studies and were either converted into the standardized mean difference (SMD) or maintained in the raw mean difference (RMD) when the studies reported the results in the same scale. Random-effects meta-analyses were performed. Results: Twenty studies were included in the systematic review and 12 were included in the meta-analysis. The main meta-analyses indicated greater decrease of biomechanical properties for RTF compared with RTNF (SMD − 0.96, 95% confidence interval [CI] − 1.43 to − 0.49, p < 0.001). Furthermore, there was a larger increase in metabolic response (RMD 4.48 mmol·L−1, 95% CI 3.19–5.78, p < 0.001), muscle damage (SMD 0.76, 95% CI 0.31–1.21, p = 0.001), and RPE (SMD 1.93, 95% CI 0.87–3.00, p < 0.001) for RTF compared with RTNF. Further exploratory subgroup analyses showed that training status (p = 0.92), timepoint (p = 0.89), load (p = 0.10), and volume (p = 0.12) did not affect biomechanical properties; however, greater loss in the movement velocity test occurred on upper limbs compared with lower limbs (p < 0.001). Blood ammonia concentration was greater after RTF than RTNF (RMD 44.66 μmol·L−1, 95% CI 32.27–57.05, p < 0.001), as was 48 h post-exercise blood creatine kinase activity (SMD 0.86, 95% CI 0.33–1.42, p = 0.002). Furthermore, although there was considerable heterogeneity in the overall analysis (I2 = 83.72%; p < 0.01), a significant difference in RPE after RTF compared with RTNF was only found for studies that did not equalize training volumes. Conclusions: In summary, RTF compared with RTNF led to a greater decrease in biomechanical properties and a simultaneous increase in metabolic response, higher muscle damage, and RPE. The exploratory analyses suggested a greater impairment in the velocity of movement test for the upper limbs, more pronounced muscle damage 48 h post-exercise, and a greater RPE in studies with non-equalized volume after the RTF session compared with RTNF. Therefore, it can be concluded that RTF leads to greater acute fatigue compared with RTNF. The higher acute fatigue after RTF can also have an important impact on chronic adaptive processes following RT; however, the greater acute fatigue following RTF can extend the time needed for recovery, which should be considered when RTF is used. Protocol Registration: The original protocol was prospectively registered (CRD42020192336) in the International Prospective Register of Systematic Reviews (PROSPERO). [ABSTRACT FROM AUTHOR]

Background: Concentrations of endogenous sex hormones fluctuate across the menstrual cycle (MC), which could have implications for exercise performance in women. At present, data are conflicting, with no consensus on whether exercise performance is affected by MC phase. Objective: To determine the effects of the MC on exercise performance and provide evidence-based, practical, performance recommendations to eumenorrheic women. Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Four databases were searched for published experimental studies that investigated the effects of the MC on exercise performance, which included at least one outcome measure taken in two or more defined MC phases. All data were meta-analysed using multilevel models grounded in Bayesian principles. The initial meta-analysis pooled pairwise effect sizes comparing exercise performance during the early follicular phase with all other phases (late follicular, ovulation, early luteal, mid-luteal and late luteal) amalgamated. A more comprehensive analysis was then conducted, comparing exercise performance between all phases with direct and indirect pairwise effect sizes through a network meta-analysis. Results from the network meta-analysis were summarised by calculating the Surface Under the Cumulative Ranking curve (SUCRA). Study quality was assessed using a modified Downs and Black checklist and a strategy based on the recommendations of the Grading of Recommendations Assessment Development and Evaluation (GRADE) working group. Results: Of the 78 included studies, data from 51 studies were eligible for inclusion in the initial pairwise meta-analysis. The three-level hierarchical model indicated a trivial effect for both endurance- and strength-based outcomes, with reduced exercise performance observed in the early follicular phase of the MC, based on the median pooled effect size (ES0.5 = − 0.06 [95% credible interval (CrI): − 0.16 to 0.04]). Seventy-three studies had enough data to be included in the network meta-analysis. The largest effect was identified between the early follicular and the late follicular phases of the MC (ES0.5 = − 0.14 [95% CrI: − 0.26 to − 0.03]). The lowest SUCRA value, which represents the likelihood that exercise performance is poor, or among the poorest, relative to other MC phases, was obtained for the early follicular phase (30%), with values for all other phases ranging between 53 and 55%. The quality of evidence for this review was classified as "low" (42%). Conclusion: The results from this systematic review and meta-analysis indicate that exercise performance might be trivially reduced during the early follicular phase of the MC, compared to all other phases. Due to the trivial effect size, the large between-study variation and the number of poor-quality studies included in this review, general guidelines on exercise performance across the MC cannot be formed; rather, it is recommended that a personalised approach should be taken based on each individual's response to exercise performance across the MC. [ABSTRACT FROM AUTHOR]

Background: Sport activities can account for up to one-third of all orofacial injuries. Mouthguards (MGs) have been proposed as a way to reduce these injuries. Objectives: To present a systematic review and meta-analysis of the effectiveness of MGs for the prevention of sports-related orofacial injuries and concussions. Methods: Using specific search terms, PubMed, Ovid Embase, and the Cumulative Index to Nursing and Allied Health Literature were searched to find studies that (1) contained original quantitative data on MGs and orofacial injuries and/or concussions, (2) included groups involved in sports or exercise activities, (3) included MG users and non-MG users, and (4) provided either risk ratios (RRs) and 95% confidence intervals (95% CIs) comparing injuries among MG users and non-MG users, or data that could be used to calculate RRs and 95% CIs. Results: Twenty-six studies met the review criteria. Investigations employed a variety of study designs, utilized different types of MGs, used widely varying injury case definitions, and had multiple methodological weaknesses. Despite these limitations, meta-analyses indicated that the use of MGs reduced the overall risk of orofacial injuries in 12 cohort trials (summary RR [nonusers/users] = 2.33, 95% CI 1.59–3.44), and 11 trials involving self-report questionnaires (summary RR [nonusers/users] = 2.32, 95% CI 1.04–5.13). The influence of MGs on concussion incidence in five cohort studies was modest (summary RR [nonusers/users] = 1.25, 95% CI 0.90–1.74). Conclusion: These data indicate that MGs should be used in sports activities where there is significant orofacial injury risk. [ABSTRACT FROM AUTHOR]

Background: In athletes, hip and groin pain is considered to be associated with hip intra-articular pathologies and hip osteoarthritis (OA). A greater understanding of the relationship between hip and groin pain and imaging findings is required. Objective: Our objective was to undertake a systematic review and meta-analysis to determine the prevalence of hip intra-articular pathologies and hip OA in athletes with and without hip and groin pain. Methods: Seven electronic databases were searched on 29 January 2018 for studies investigating the prevalence of hip intra-articular pathologies and hip OA using X-ray, magnetic resonance imaging, magnetic resonance arthrography or computed tomography. The search, study selection, quality appraisal and data extraction were performed by two independent reviewers. When studies were considered homogenous, meta-analysis was undertaken. A strength of evidence was given to pooled results. Results: Twenty studies reporting on the prevalence of hip intra-articular pathologies and hip OA in athletes were identified. Included studies were considered moderate to high risk of bias, with only three studies adjudged as low risk of bias. In asymptomatic athletes, limited evidence identified a labral tear prevalence of 54% per person and moderate evidence of 33% per hip. In symptomatic athletes, moderate evidence of a labral tear prevalence of 20% per hip was found. Moderate evidence of a cartilage defect prevalence of 10% per person was reported in asymptomatic athletes. In symptomatic athletes, cartilage defect prevalence was 7–40%. In asymptomatic athletes, the prevalence of hip OA was 0–17%, compared with 2% in symptomatic athletes. Conclusion: The prevalence of hip intra-articular pathologies and hip OA in symptomatic and asymptomatic athletes is variable. Labral tears and cartilage defects appear to be seen often in athletes with and without pain. Hip OA is rarely seen in athletes either with or without hip and groin pain. Study Registration: PROSPERO registration CRD42017082457. [ABSTRACT FROM AUTHOR]

Background: Previous studies have suggested that exercise training improves cardiac autonomic drive in young and middle-aged adults. In this study, we discuss the benefits for the elderly. Objectives: We aimed to establish whether exercise still increases heart rate variability (HRV) beyond the age of 60 years, and to identify which training factors influence HRV gains in this population. Methods: Interventional controlled and non-controlled studies were selected from the PubMed, Ovid, Cochrane and Google Scholar databases. Only interventional endurance training protocols involving healthy subjects aged 60 years and over, and measuring at least one heart rate global or parasympathetic index, such as the standard deviation of the normal-to-normal intervals (SDNN), total frequency power (Ptot), root mean square of successive differences between adjacent NN intervals (RMSSD), or high frequency power (HF) before and after the training intervention, were included. HRV parameters were pooled separately from short-term and 24 h recordings for analysis. Risks of bias were assessed using the Methodological Index for Non-Randomized Studies and the Cochrane risk of bias tool. A random-effects model was used to determine effect sizes (Hedges' g) for changes, and heterogeneity was assessed using Q and I statistics. Results: Twelve studies, seven of which included a control group, including 218 and 111 subjects, respectively (mean age 69.0 ± 3.2 and 68.6 ± 2.5), were selected for meta-analysis. Including the 12 studies demonstrated homogeneous significant effect sizes for short-term (ST)-SDNN and 24 h-SDNN, with effect sizes of 0.366 (95% CI 0.185–547) and 0.442 (95% CI 0.144–0.740), respectively. Controlled study analysis demonstrated homogeneous significant effect sizes for 24 h-SDNN with g = 0.721 (95% CI 0.184–1.257), and 24 h-Ptot with g = 0.731 (95% CI 0.195–1.267). Meta-regression analyses revealed positive relationships between ST-SDNN effect sizes and training frequency ( Tau res 2 = 0.000; I res 2 = 0.000; p = 0.0462). Conclusion: This meta-analysis demonstrates a positive effect of endurance-type exercise on autonomic regulation in older adults. However, the selected studies expressed some risks of bias. We conclude that chronic endurance exercise leads to HRV improvements in a linear frequency–response relationship, encouraging the promotion of high-frequency training programmes in older adults. [ABSTRACT FROM AUTHOR]

Background: Subtle differences in chronological age within sport (bi-) annual-age groupings can contribute to immediate participation and long-term attainment discrepancies; known as the relative age effect. Voluminous studies have examined relative age effects in male sport; however, their prevalence and context-specific magnitude in female sport remain undetermined.Objective: The objective of this study was to determine the prevalence and magnitude of relative age effects in female sport via examination of published data spanning 1984-2016.Methods: Registered with PROSPERO (No. 42016053497) and using Preferred Reporting Items for Systematic Reviews and Meta-analysis systematic search guidelines, 57 studies were identified, containing 308 independent samples across 25 sports. Distribution data were synthesised using odds ratio meta-analyses, applying an invariance random-effects model. Follow-up subgroup category analyses examined whether relative age effect magnitudes were moderated by age group, competition level, sport type, sport context and study quality.Results: When comparing the relatively oldest (quartile 1) vs. youngest (quartile 4) individuals across all female sport contexts, the overall pooled estimate identified a significant but small relative age effect (odds ratio = 1.25; 95% confidence interval 1.21-1.30; p = 0.01; odds ratio adjusted = 1.21). Subgroup analyses revealed the relative age effect magnitude was higher in pre-adolescent (≤ 11 years) and adolescent (12-14 years) age groups and at higher competition levels. Relative age effect magnitudes were higher in team-based and individual sport contexts associated with high physiological demands.Conclusion: The findings highlight relative age effects are prevalent across the female sport contexts examined. Relative age effect magnitude is moderated by interactions between developmental stages, competition level and sport context demands. Modifications to sport policy, organisational and athlete development system structure, as well as practitioner intervention are recommended to prevent relative age effect-related participation and longer term attainment inequalities. [ABSTRACT FROM AUTHOR]

Background: Muscle lesions account for one-third of sport-related injuries, thus representing a substantial problem for both players and their teams. The use of platelet-rich plasma (PRP) injections is rapidly growing in clinical practice, prompted by an unmet clinical need with a large commercial market. However, after early reports of positive preliminary experience, higher quality studies recently questioned the real benefit provided by PRP injections to promote muscle healing and return to sport.Objective: To evaluate the effect of platelet-rich plasma (PRP) injections on outcomes following acute muscle injuries.Design: Meta-analysis of randomized, controlled trials (RCTs), Level I.Data sources: PubMed (MEDLINE), Cochrane (CENTRAL), Web of Science, clinicaltrials.gov, who.int, isrctn.com, greylit.org, opengrey.eu.Eligibility criteria: RCTs investigating the effect of PRP for the treatment of acute muscle injuries against at least one control group including patients treated with placebo injection or physical therapy. The outcomes evaluated were time to return to sport, re-injuries, complications, pain, muscle strength, range of motion (ROM)/flexibility, muscle function, and imaging.Results: Six studies, involving 374 patients, were included in the meta-analysis. The time to return to sport evaluated in all six studies was significantly shorter in patients treated with PRP (mean difference = − 7.17 days). However, if only the double-blind studies (n = 2) or studies including only hamstring injuries (n = 3) were considered, non-significant differences were found. Re-injuries (relative risk = − 0.03) and complications (relative risk = 0.01) were also similar between the two groups (p > 0.05), nor were any substantial differences found regarding pain, muscle strength, ROM/flexibility, muscle function, and imaging. The performance bias was high risk due to the lack of patient blinding in four studies. The quality of evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) was therefore low or very low.Conclusions: The promising biological rationale, the positive preclinical findings, and the successful early clinical experience of PRP injections are not confirmed by the recent high-level RCTs. Therefore any benefit in terms of pain, function, return to sport, and recurrence using PRP injections for the treatment of acute muscle injuries is not supported. Due to the bias in the studies, the heterogeneity of the findings, and the limited sample size, the evidence should be considered to be of low or very low quality. [ABSTRACT FROM AUTHOR]

Background: Visual, vestibular, and somatosensory systems contribute to postural control. Chronic ankle instability (CAI) patients have been observed to have a reduced ability to dynamically shift their reliance among sources of sensory information and rely more heavily on visual information during a single-limb stance relative to uninjured controls. Balance training is proven to improve postural control but there is a lack of evidence regarding the ability of balance training programs to alter the reliance on visual information in CAI patients.Objective: Our objective was to determine if balance training alters the reliance on visual information during static stance in CAI patients.Methods: The PubMed, CINAHL, and SPORTDiscus databases were searched from their earliest available date to October 2017 using a combination of keywords. Study inclusion criteria consisted of (1) using participants with CAI; (2) use of a balance training intervention; and (3) calculation of an objective measure of static postural control during single-limb stance with eyes open and eyes closed. Sample sizes, means, and standard deviations of single-leg balance measures for eyes-open and eyes-closed testing conditions before and after balance training were extracted from the included studies. Eyes-open to eyes-closed effect sizes [Hedges’ g and 95% confidence intervals (CI)] before and after balance training were calculated, and between-study variability for heterogeneity and potential risks of publication bias were examined.Results: Six studies were identified. The overall eyes-open to eyes-closed effect size difference between pre- and post-intervention assessments was not significant (Hedges’ g effect size = 0.151, 95% CI = − 0.151 to 0.453, p = 0.26). This result indicates that the utilization of visual information in individuals with CAI during the single-leg balance is not altered after balance training. Low heterogeneity (Q(5) = 2.96, p = 0.71, I2 = 0%) of the included studies and no publication bias were found.Conclusion: On the basis of our systematic review with meta-analysis, it appears that traditional balance training protocols do not alter the reliance on visual information used by CAI patients during a single-leg stance. [ABSTRACT FROM AUTHOR]

Background: The associations between internal and external measures of training load and intensity are important in understanding the training process and the validity of specific internal measures.Objectives: We aimed to provide meta-analytic estimates of the relationships, as determined by a correlation coefficient, between internal and external measures of load and intensity during team-sport training and competition. A further aim was to examine the moderating effects of training mode on these relationships.Methods: We searched six electronic databases (Scopus, Web of Science, PubMed, MEDLINE, SPORTDiscus, CINAHL) for original research articles published up to September 2017. A Boolean search phrase was created to include search terms relevant to team-sport athletes (population; 37 keywords), internal load (dependent variable; 35 keywords), and external load (independent variable; 81 keywords). Articles were considered for meta-analysis when a correlation coefficient describing the association between at least one internal and one external measure of session load or intensity, measured in the time or frequency domain, was obtained from team-sport athletes during normal training or match-play (i.e., unstructured observational study). The final data sample included 122 estimates from 13 independent studies describing 15 unique relationships between three internal and nine external measures of load and intensity. This sample included 295 athletes and 10,418 individual session observations. Internal measures were session ratings of perceived exertion (sRPE), sRPE training load (sRPE-TL), and heart-rate-derived training impulse (TRIMP). External measures were total distance (TD), the distance covered at high and very high speeds (HSRD ≥ 13.1–15.0 km h−1 and VHSRD ≥ 16.9–19.8 km h−1, respectively), accelerometer load (AL), and the number of sustained impacts (Impacts > 2–5 G). Distinct training modes were identified as either mixed (reference condition), skills, metabolic, or neuromuscular. Separate random effects meta-analyses were conducted for each dataset (n = 15) to determine the pooled relationships between internal and external measures of load and intensity. The moderating effects of training mode were examined using random-effects meta-regression for datasets with at least ten estimates (n = 4). Magnitude-based inferences were used to interpret analyses outcomes.Results: During all training modes combined, the external load relationships for sRPE-TL were possibly very large with TD [r = 0.79; 90% confidence interval (CI) 0.74 to 0.83], possibly large with AL (r = 0.63; 90% CI 0.54 to 0.70) and Impacts (r = 0.57; 90% CI 0.47 to 0.64), and likely moderate with HSRD (r = 0.47; 90% CI 0.32 to 0.59). The relationship between TRIMP and AL was possibly large (r = 0.54; 90% CI 0.40 to 0.66). All other relationships were unclear or not possible to infer (r range 0.17–0.74, n = 10 datasets). Between-estimate heterogeneity [standard deviations (SDs) representing unexplained variation; τ] in the pooled internal–external relationships were trivial to extremely large for sRPE (τ range = 0.00–0.47), small to large for sRPE-TL (τ range = 0.07–0.31), and trivial to moderate for TRIMP (τ range= 0.00–0.17). The internal–external load relationships during mixed training were possibly very large for sRPE-TL with TD (r = 0.82; 90% CI 0.75 to 0.87) and AL (r = 0.81; 90% CI 0.74 to 0.86), and TRIMP with AL (r = 0.72; 90% CI 0.55 to 0.84), and possibly large for sRPE-TL with HSRD (r = 0.65; 90% CI 0.44 to 0.80). A reduction in these correlation magnitudes was evident for all other training modes (range of the change in r when compared with mixed training − 0.08 to − 0.58), with these differences being unclear to possibly large. Training mode explained 24–100% of the between-estimate variance in the internal–external load relationships.Conclusion: Measures of internal load derived from perceived exertion and heart rate show consistently positive associations with running- and accelerometer-derived external loads and intensity during team-sport training and competition, but the magnitude and uncertainty of these relationships are measure and training mode dependent. [ABSTRACT FROM AUTHOR]

Background: Athletes may complete consecutive exercise sessions with limited recovery time between bouts (e.g. ≤ 4 h). Nutritional strategies that optimise post-exercise recovery in these situations are therefore important. Objective: This two-part review investigated the effect of consuming carbohydrate (CHO) and protein with water (W) following exercise on subsequent athletic (endurance/anaerobic exercise) performance. Data Sources: Studies were identified by searching the online databases SPORTDiscus, PubMed, Web of Science and Scopus. Study Eligibility Criteria and Interventions: Investigations that measured endurance performance (≥ 5 min duration) ≤ 4 h after a standardised exercise bout (any type) under the following control vs. intervention conditions were included: Part 1: W vs. CHO ingested with an equal volume of W (CHO + W); and, Part 2: CHO + W vs. protein (PRO) ingested with CHO and an equal volume of W (PRO + CHO + W), where CHO or energy intake was matched. Study Appraisal and Synthesis Methods: Publications were examined for bias using the Rosendal scale. Random-effects meta-analyses and meta-regression analyses were conducted to evaluate intervention efficacy. Results: The quality assessment yielded a Rosendal score of 63 ± 9% (mean ± standard deviation). Part 1: 45 trials ( n = 486) were reviewed. Ingesting CHO + W (102 ± 50 g CHO; 0.8 ± 0.6 g CHO kg h) improved exercise performance compared with W (1.6 ± 0.7 L); % mean power output = 4.0, 95% confidence interval 3.2-4.7 ( I = 43.9). Improvement was attenuated when participants were 'Fed' (a meal 2-4 h prior to the initial bout) as opposed to 'Fasted' ( p = 0.012). Part 2: 13 trials ( n = 125) were reviewed. Ingesting PRO + CHO + W (35 ± 26 g PRO; 0.5 ± 0.4 g PRO kg) did not affect exercise performance compared with CHO + W (115 ± 61 g CHO; 0.6 ± 0.3 g CHO·kg body mass h; 1.2 ± 0.6 L); % mean power output = 0.5, 95% confidence interval − 0.5 to 1.6 ( I = 72.9). Conclusions: Athletes with limited time for recovery between consecutive exercise sessions should prioritise CHO and fluid ingestion to enhance subsequent athletic performance. PROSPERO Registration Number: CRD42016046807. [ABSTRACT FROM AUTHOR]

Background: High-intensity interval training (HIIT) is promoted as a time-efficient strategy to improve body composition. Objective: The aim of this meta-analysis was to assess the efficacy of HIIT in reducing total, abdominal, and visceral fat mass in normal-weight and overweight/obese adults. Methods: Electronic databases were searched to identify all related articles on HIIT and fat mass. Stratified analysis was performed using the nature of HIIT (cycling versus running, target intensity), sex and/or body weight, and the methods of measuring body composition. Heterogeneity was also determined Results: A total of 39 studies involving 617 subjects were included (mean age 38.8 years ± 14.4, 52% females). HIIT significantly reduced total ( p = 0.003), abdominal ( p = 0.007), and visceral ( p = 0.018) fat mass, with no differences between the sexes. A comparison showed that running was more effective than cycling in reducing total and visceral fat mass. High-intensity (above 90% peak heart rate) training was more successful in reducing whole body adiposity, while lower intensities had a greater effect on changes in abdominal and visceral fat mass. Our analysis also indicated that only computed tomography scan or magnetic resonance imaging showed significant abdominal and/or visceral fat-mass loss after HIIT interventions. Conclusion: HIIT is a time-efficient strategy to decrease fat-mass deposits, including those of abdominal and visceral fat mass. There was some evidence of the greater effectiveness of HIIT running versus cycling, but owing to the wide variety of protocols used and the lack of full details about cycling training, further comparisons need to be made. Large, multicenter, prospective studies are required to establish the best HIIT protocols for reducing fat mass according to subject characteristics. [ABSTRACT FROM AUTHOR]

Background: Zinc is an essential trace element that has been implicated in numerous biological functions, including immunity, energy metabolism and antioxidative processes. Recent evaluations of the literature have provided evidence of significant acute changes in zinc metabolism following a bout of aerobic exercise. Objective: The aim of this study was to determine the zinc status of trained athletes compared with control populations, as described in cross-sectional studies. Design: We conducted a systematic literature search of the PubMed, Scopus, SPORTDiscus and Cochrane Library electronic databases from inception to 28 January 2016 to identify cross-sectional studies that determined the zinc status of athletes compared with a control population. Meta-analysis of the differences in serum zinc concentration and dietary zinc intake between groups were conducted. Results: Twelve studies were included in the systematic review. Of the included studies, nine and eight studies provided sufficient data for the meta-analysis of serum zinc concentration and dietary zinc intake, respectively. Serum zinc concentration was significantly lower in athletes [− 0.93 μmol/L, 95% confidence interval (CI) − 1.62 to − 0.23] despite significantly higher dietary zinc intake compared with the control population (2.57 mg/day, 95% CI 0.97-4.16). Data on erythrocyte and urinary zinc from the included studies were insufficient for meta-analysis. Conclusions: Despite higher total dietary zinc intake, athletes generally have lower serum zinc concentration, which suggests that athletes have higher requirement of zinc than those who are physically inactive. Further investigations of zinc metabolism during exercise and dietary zinc requirement in active populations are needed to establish evidence-based recommendations. [ABSTRACT FROM AUTHOR]

Background: There is a necessity for numerous sports to develop strength and aerobic capacity simultaneously, placing a significant demand upon the practice of effective concurrent training methods. Concurrent training requires the athlete to perform both resistance and endurance exercise within a training plan. This training paradigm has been associated with an 'interference effect', with attenuated strength adaptation in comparison to that following isolated resistance training. The effectiveness of the training programme rests on the intricacies of manipulating acute training variables, such as exercise sequence. The research, in the most part, does not provide a clarity of message as to whether intra-session exercise sequence has the potential to exacerbate or mitigate the interference effect associated with concurrent training methods. Objective: The aim of the systematic review and meta-analysis was to assess whether intra-session concurrent exercise sequence modifies strength-based outcomes associated with the interference effect. Methods: Ten studies were identified from a systematic review of the literature for the outcomes of lower-body dynamic and static strength, lower-body hypertrophy, maximal aerobic capacity and body fat percentage. Each study examined the effect of intra-session exercise sequence on the specified outcomes, across a prolonged (≥5 weeks) concurrent training programme in healthy adults. Results: Analysis of pooled data indicated that resistance-endurance exercise sequence had a positive effect for lower-body dynamic strength, in comparison to the alternate sequence (weighted mean difference, 6.91% change; 95% confidence interval 1.96, 11.87 change; p = 0.006), with no effect of exercise sequence for lower-body muscle hypertrophy (weighted mean difference, 1.15% change; 95% confidence interval −1.56, 3.87 change; p = 0.40), lower-body static strength (weighted mean difference, −0.04% change; 95% confidence interval −3.19, 3.11 change; p = 0.98), or the remaining outcomes of maximal aerobic capacity and body fat percentage ( p > 0.05). Conclusion: These results indicate that the practice of concurrent training with a resistance followed by an endurance exercise order is beneficial for the outcome of lower-body dynamic strength, while alternating the order of stimuli offers no benefit for training outcomes associated with the interference effect. [ABSTRACT FROM AUTHOR]

Background: There is currently no systematic review examining the effects of vitamin D supplementation among athletes. A rigorous systematic review and meta-analysis is important to provide a balanced view of current knowledge on the effect of vitamin D on serum 25-hydroxyvitamin D [25(OH)D] concentrations and physical performance. Objectives: This systematic review of randomized controlled trials (RCTs) evaluated the effects of oral vitamin D supplementation on serum 25(OH)D concentrations and physical performance in athletes. Methods: Multiple electronic databases were searched, and study eligibility, methodological quality assessment, and data extraction were completed independently and in duplicate. Studies were stratified by baseline vitamin D sufficiency, season, and latitude. A cut-off of 30 ng/ml (75 nmol/l) of 25(OH)D was used for sufficiency. Absolute mean differences (AMDs) between vitamin D and placebo using random effects analysis, and heterogeneity using Q statistic and I index, were calculated. AMD with 95% confidence interval (CI), p value, and I are reported. Results: In total, 13 RCTs (2005-2016) with 532 athletes (vitamin D 311, placebo 221) were eligible. A total of 433 athletes (vitamin D 244, placebo 189) had complete outcome data. Among athletes with baseline values suggesting insufficiency, vitamin D supplementation led to significant increases from 3000 IU (AMD 15.2 ng/ml; 95% CI 10.7-19.7, p < 0.0001, I = 0%) and 5000 IU (AMD 27.8 ng/ml; 95% CI 16.9-38.8, p < 0.0001, I = 78%) per day at >45° latitudes. Both doses led to sufficiency concentrations during winter months. Among athletes with baseline vitamin D suggesting sufficiency, serum 25(OH)D sufficiency was maintained from different doses at both latitudes. Of 13 included trials, only seven measured different physical performances and none demonstrated a significant effect of vitamin D supplementation during 12 weeks of follow-up. Conclusion: Despite achieving sufficiency in vitamin D concentrations from ≥3000 IU supplementation, physical performance did not significantly improve. Between-study heterogeneity was large, and well-designed RCTs examining the effect of vitamin D supplementation on serum 25(OH)D concentrations, physical performance, and injuries in different sports, latitudes, ethnicities, and vitamin D status are needed. [ABSTRACT FROM AUTHOR]

Background: Fluid replacement during cycling exercise evolves on a spectrum from simply drinking to thirst to planned structured intake, with both being appropriate recommendations. However, with mixed findings suggesting fluid intake may or may not improve endurance cycling performance (ECP) in a diverse range of trained individuals, there is a clear need for summarised evidence regarding the effect of fluid consumption on ECP. Objectives: (1) Determine the magnitude of the effect of drinking fluid on performance during cycling exercise tasks of various durations, compared with no drinking; (2) examine the relationship between rates of fluid intake and ECP; and (3) establish fluid intake recommendations based on the observations between rates of fluid intake and ECP. Study Design: Meta-analysis. Methods: Studies were located via database searches and cross-referencing. Performance outcomes were converted to a similar metric to represent percentage change in power output. Fixed- and random-effects weighted mean effect summaries and meta-regression analyses were used to identify the impact of drinking fluid on ECP. Results: A limited number of research manuscripts ( n = 9) met the inclusion criteria, producing 15 effect estimates. Meta-regression analyses demonstrated that the impact of drinking on ECP under 20-33 °C ambient temperatures was duration-dependent. Fluid consumption of, on average, 0.29 mL/kg body mass/min impaired 1 h high-intensity (80% peak oxygen uptake [ $${\dot{\text{V}}}$$ o]) ECP by −2.5 ± 0.8% (95% confidence interval [CI] −4.1 to −0.9%) compared with no fluid ingestion. In contrast, during >1 to ≤2 h and >2 h moderate-intensity (60-70% $${\dot{\text{V}}}$$ o) cycling exercise, ECP improved by 2.1 ± 1.5% (95% CI 1.2-2.9%) and 3.2 ± 1.2% (95% CI 0.8-5.6%), respectively, with fluid ingestion compared with no fluid intake. The associated performance benefits were observed when the rates of fluid intake were in the range of 0.15-0.20 mL/kg body mass/min for >1 to ≤2 h cycling exercise and ad libitum or 0.14-0.27 mL/kg body mass/min for cycling exercise >2 h. Conclusions: A rate of fluid consumption of between 0.15 and 0.34 mL/kg body mass/min during high-intensity 1 h cycling exercise is associated with reductions in ECP. When cycling at moderate intensity for >1 to ≤2 h, cyclists should expect a gain in performance of at least 2% if fluid is consumed at a rate of 0.15-0.20 mL/kg body mass/min. For cycling exercise >2 h conducted at moderate intensity, consuming fluid ad libitum or at a rate of 0.14-0.27 mL/kg body mass/min should improve performance by at least 3%. Until further research is conducted, these recommendations should be used as a guide to inform hydration practices. [ABSTRACT FROM AUTHOR]

Background: The athlete's heart is associated with physiological remodeling as a consequence of repetitive cardiac loading. The effect of exercise training on left ventricular (LV) cardiac strain and twist mechanics are equivocal, and no meta-analysis has been conducted to date. Objective: The objective of this systematic review and meta-analysis was to review the literature pertaining to the effect of different forms of athletic training on cardiac strain and twist mechanics and determine the influence of traditional and contemporary sporting classifications on cardiac strain and twist mechanics. Methods: We searched PubMed/MEDLINE, Web of Science, and ScienceDirect for controlled studies of aged-matched male participants aged 18-45 years that used two-dimensional (2D) speckle tracking with a defined athlete sporting discipline and a control group not engaged in training programs. Data were extracted independently by two reviewers. Random-effects meta-analyses, subgroup analyses, and meta-regressions were conducted. Results: Our review included 13 studies with 945 participants (controls n = 355; athletes n = 590). Meta-analyses showed no athlete-control differences in LV strain or twist mechanics. However, moderator analyses showed greater LV twist in high-static low-dynamic athletes ( d = -0.76, 95% confidence interval [CI] -1.32 to -0.20; p < 0.01) than in controls. Peak untwisting velocity (PUV) was greater in high-static low-dynamic athletes ( d = -0.43, 95% CI -0.84 to -0.03; p < 0.05) but less than controls in high-static high-dynamic athletes ( d = 0.79, 95% CI 0.002-1.58; p = 0.05). Elite endurance athletes had significantly less twist and apical rotation than controls ( d = 0.68, 95% CI 0.19-1.16, p < 0.01; d = 0.64, 95% CI 0.27-1.00, p = 0.001, respectively) but no differences in basal rotation. Meta-regressions showed LV mass index was positively associated with global longitudinal ( b = 0.01, 95% CI 0.002-0.02; p < 0.05), whereas systolic blood pressure was negatively associated with PUV ( b = -0.06, 95% CI -0.13 to -0.001; p = 0.05). Conclusion: Echocardiographic 2D speckle tracking can identify subtle physiological differences in adaptations to cardiac strain and twist mechanics between athletes and healthy controls. Differences in speckle tracking echocardiography-derived parameters can be identified using suitable sporting categorizations. [ABSTRACT FROM AUTHOR]

Background: External mechanical power is considered to be one of the most important characteristics with regard to sport performance. Objective: The purpose of this meta-analysis was to examine the effect of load on kinetic variables such as mean and peak power during bench press and bench press throw, thus integrating the findings of various studies to provide the strength and conditioning professional with more reliable evidence upon which to base their program design. Methods: A search of electronic databases (MEDLINE, PubMed, Google Scholar, and Web of Science) was conducted to identify all publications up to 31 October 2015. Hedges' g (95 % confidence interval) was estimated using a weighted random-effect model, due to the heterogeneity ( I ) of the studies. Egger's test was used to evaluate possible publication bias in the meta-analysis. A total of 11 studies with 434 subjects and 7680 effect sizes met the inclusion criterion and were included in the statistical analyses. Load in each study was labeled as one of three intensity zones: zone 1 represented an average intensity ranging from 0 to 30 % of one repetition maximum (1RM); zone 2 between 30 and 70 % of 1RM; and zone 3 ≥ 70 % of 1RM. Results: These results showed different optimal loads for each exercise examined. Moderate loads (from >30 to <70 % of 1RM) appear to provide the optimal load for peak power and mean power in the bench press exercise. Lighter loads (<30 % of 1RM) appear to provide the highest mean and highest peak power production in the bench press throw exercise. However, a substantial heterogeneity was detected I > 75 %. Conclusion: The current meta-analysis of published literature provides evidence for exercise-specific optimal power loading for upper body exercises. [ABSTRACT FROM AUTHOR]

Background: Recent research into the use of dietary nitrates and their role in vascular function has led to it becoming progressively more popular amongst athletes attempting to enhance performance. Objective: The objective of this review was to perform a systematic review and meta-analysis of the literature to evaluate the effect of dietary nitrate (NO ) supplementation on endurance exercise performance. An additional aim was to determine whether the performance outcomes are affected by potential moderator variables. Data sources: Relevant databases such as Cochrane Library, Embase, PubMed, Ovid, Scopus and Web of Science were searched for the following search terms 'nitrates OR nitrate OR beetroot OR table beet OR garden beet OR red beet AND exercise AND performance' from inception to October 2015. Study selection: Studies were included if a placebo versus dietary nitrate-only supplementation protocol was able to be compared, and if a quantifiable measure of exercise performance was ≥30 s (for a single bout of exercise or the combined total for multiple bouts). Study appraisal and synthesis: The literature search identified 1038 studies, with 47 (76 trials) meeting the inclusion criteria. Data from the 76 trials were extracted for inclusion in the meta-analysis. A fixed-effects meta-analysis was conducted for time trial (TT) ( n = 28), time to exhaustion (TTE) ( n = 22) and graded-exercise test (GXT) ( n = 8) protocols. Univariate meta-regression was used to assess potential moderator variables (exercise type, dose duration, NO type, study quality, fitness level and percentage nitrite change). Results: Pooled analysis identified a trivial but non-significant effect in favour of dietary NO supplementation [effect size (ES) = −0.10, 95 % Cl = −0.27 to 0.06, p > 0.05]. TTE trials had a small to moderate statistically significant effect in favour of dietary NO supplementation (ES = 0.33, 95 % Cl = 0.15-0.50, p < 0.01). GXT trials had a small but non-significant effect in favour of dietary NO supplementation in GXT performance measures (ES = 0.25, 95 % Cl = −0.06 to 0.56, p > 0.05). No significant heterogeneity was detected in the meta-analysis. No statistically significant effects were observed from the meta-regression analysis. Conclusion: Dietary NO supplementation is likely to elicit a positive outcome when testing endurance exercise capacity, whereas dietary NO supplementation is less likely to be effective for time-trial performance. Further work is needed to understand the optimal dosing strategies, which population is most likely to benefit, and under which conditions dietary nitrates are likely to be most effective for performance. [ABSTRACT FROM AUTHOR]

Background: Physical activity has been associated with reduced oxidative stress (OS) in observational studies and clinical trials. Objective: The purpose of this systematic review and meta-analysis of controlled trials was to determine the effect of physical exercise on OS parameters. Methods: We conducted a systematic review of the literature up to March 2016 that included the following databases: PubMed, SCOPUS, and Web of Science. A keyword combination referring to exercise training and OS was included as part of a more thorough search process. We also manually searched the reference lists of the articles. From an initial 1573 references, we included 30 controlled trials (1346 participants) in the qualitative analysis, 19 of which were included in the meta-analysis. All trials were conducted in humans and had at least one exercise intervention and a paired control group. Using a standardized protocol, two investigators independently abstracted data on study design, sample size, participant characteristics, intervention, follow-up duration, outcomes, and quantitative data for the meta-analysis. Thus, the investigators independently assigned quality scores with a methodological quality assessment (MQA). Results: The agreement level between the reviewers was 85.3 %. Discrepancies were solved in a consensus meeting. The MQA showed a total score in the quality index between 40 and 90 % and a mean quality of 55 %. Further, in a random-effects model, data from each trial were pooled and weighted by the inverse of the total variance. Physical training was associated with a significant reduction in pro-oxidant parameters (standard mean difference [SMD] -1.08; 95 % confidence interval [CI] -1.57 to -0.58; p < 0.001) and an increase in antioxidant capacity (SMD 1.45; 95 % CI 0.83-2.06; p < 0.001). Conclusion: The pooled analysis revealed that regardless of intensity, volume, type of exercise, and studied population, the antioxidant indicators tended to increase and pro-oxidant indicators tended to decrease after training. Therefore, we conclude that exercise training seems to induce an antioxidant effect. Thus, it is suggested that people practice some kind of exercise to balance the redox state, regardless of their health status, to improve health-related outcomes. [ABSTRACT FROM AUTHOR]

Background: Cardiorespiratory fitness (CRF) among people with severe mental illness (SMI) (i.e., schizophrenia, bipolar disorder, and major depressive disorder) is a critical clinical risk factor given its relationship to cardiovascular disease and premature mortality. Objectives: This study aimed to: (1) investigate the mean CRF in people with SMI versus healthy controls; (2) explore moderators of CRF; and (3) investigate whether CRF improved with exercise interventions and establish if fitness improves more than body mass index following exercise interventions. Methods: Major electronic databases were searched systematically. A meta-analysis calculating Hedges' g statistic was undertaken. Results: Across 23 eligible studies, pooled mean CRF was 28.7 mL/kg/min [95 % confidence interval (CI) 27.3 to 30.0 mL/kg/min, p < 0.001, n = 980]. People with SMI had significantly lower CRF compared with controls ( n = 310) (Hedges' g = −1.01, 95 % CI −1.18 to −0.85, p < 0.001). There were no differences between diagnostic subgroups. In a multivariate regression, first-episode ( β = 6.6, 95 % CI 0.6-12.6) and inpatient ( β = 5.3, 95 % CI 1.6-9.0) status were significant predictors of higher CRF. Exercise improved CRF (Hedges' g = 0.33, 95 % CI = 0.21-0.45, p = 0.001), but did not reduce body mass index. Higher CRF improvements were observed following interventions at high intensity, with higher frequency (at least three times per week) and supervised by qualified personnel (i.e., physiotherapists and exercise physiologists). Conclusion: The multidisciplinary treatment of people with SMI should include a focus on improving fitness to reduce all-cause mortality. Qualified healthcare professionals supporting people with SMI in maintaining an active lifestyle should be included as part of multidisciplinary teams in mental health treatment. [ABSTRACT FROM AUTHOR]

Background: Increased knee abduction angle during activity is suggested to be a risk factor for sustaining an anterior cruciate ligament (ACL) injury or developing patellofemoral pain syndrome (PFPS). Knowledge of the modifiable mechanisms that are associated with increased knee abduction will aid in the appropriate design of preventive and rehabilitative strategies for these injuries. Objective: Our objective was to systematically review modifiable mechanisms contributing to increased knee abduction in healthy people and in individuals with an ACL injury or PFPS. Methods: We performed a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched the databases MEDLINE, CINAHL, and Embase until September 2015. Inclusion criteria were studies in healthy individuals and/or those with ACL injury or PFPS reporting (1) muscle strength, muscle activation, proprioception, and/or range of motion (ROM) and (2) knee abduction angle assessed with either motion analysis or visual observation during weight-bearing activity. Results: In total, 33 articles were included. Reduced trunk strength, reduced gluteus maximus amplitude, decreased ankle ROM, and increased hip external rotation ROM were moderately associated with increased knee abduction angle ( r −0.34 or higher, standardized difference in means (SDM) greater than −0.39, p < 0.05, articles n = 3, total sample size n = 101-114) in healthy individuals. Decreased strength of hip abductors, external rotators, and extensors and knee flexors were at most weakly associated with increased knee abduction angle ( r ≤ 0.21, p = 0.013-0.426, articles n = 2-9, total sample size n = 80-311). Too few articles included patients with knee injury to be included in any meta-analysis. Conclusion: The associations identified in this review indicate that investigation of strengthening of the trunk muscles, and improvement of gluteus maximus activation and ankle ROM to change knee kinematics is merited. Studies on modifiable factors associated with increased knee abduction angle in people with knee injury are needed. [ABSTRACT FROM AUTHOR]

Background: The global rise in obesity prevalence among children and adolescents has been linked to modifiable lifestyle factors, including lack of physical activity. However, no known meta-analysis has been conducted on the effects of exercise intervention on body composition and cardiometabolic risk factors in overweight and obese adolescents. Objectives: The aim of this study was to (1) estimate whether exercise intervention meaningfully improves body composition and cardiometabolic risk factors in overweight and obese adolescents; and (2) discuss the implications of the findings in terms of primary healthcare provision and public health policy, using New Zealand as an exemplar context. Data Sources: Electronic databases (PubMed, Web of Science, SPORTDiscus, Google Scholar) from inception to May 2015. The reference lists of eligible articles and relevant reviews were also checked. Study Selection: Inclusion criteria were (1) randomized controlled trial; (2) structured exercise intervention, alone or combined with any other kind of intervention; (3) control group received no structured exercise or behavioural modification designed to increase physical activity; (4) participants overweight or obese (body mass index [BMI] ≥85th percentile); and (5) participants aged between 10 and 19 years. Appraisal and Synthesis Methods: Initially, 1667 articles were identified. After evaluation of study characteristics, quality and validity, data from 13 articles (15 trials) involving 556 participants (176 male, 193 female, 187 unknown) were extracted for meta-analysis. Meta-analyses were completed on five body composition parameters and ten cardiometabolic parameters. Effect sizes (ESs) were calculated as mean differences, as well as standardized mean differences in order to determine effect magnitude. Results: Exercise intervention reduced BMI (mean 2.0 kg/m, 95 % CI 1.5-2.5; ES moderate), body weight (mean 3.7 kg, 95 % CI 1.7-5.8; ES small), body fat percentage (3.1 %, 95 % CI 2.2-4.1; ES small), waist circumference (3.0 cm, 95 % CI 1.3-4.8; ES small), but the increase (improvement) in lean mass was trivial (mean 1.6 kg, 95 % CI 0.5-2.6). The response to an oral glucose tolerance test following exercise intervention was for a decrease in the area under the curve for insulin (mean 162 μU/μl, 95 % CI 93-231; ES large) and blood glucose (mean 39 mg/dl, 95 % CI 9.4-69; ES moderate). Improvements in the homeostatic model assessment were also noted (mean 1.0, 95 % CI 0.7-1.4; ES moderate) and systolic blood pressure (mean 7.1 mmHg, 95 % CI 3.5-10.7; ES moderate). The effects of exercise on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting insulin and fasting blood glucose were inconclusive. Limitations: Most of the included trials were short term (6-36 weeks) and 13 had methodological limitations. Additionally, the meta-analyses for some of the secondary outcomes had a small number of participants or substantial statistical heterogeneity. Conclusions: The current evidence suggests that exercise intervention in overweight and obese adolescents improves body composition, particularly by lowering body fat. The limited available evidence further indicates that exercise intervention may improve some cardiometabolic risk factors. [ABSTRACT FROM AUTHOR]

Background: Exercise training (ExT) prompts multiple beneficial adaptations associated with vascular health, such as increases in skeletal muscle capillarization and vascular dilator function and decreases in arterial stiffness. However, whether ExT performed in hypoxic conditions induces enhanced effects is unclear. Objective: We sought to systematically review the literature and determine whether hypoxic ExT leads to superior vascular adaptations compared with normoxic ExT. Methods: We searched MEDLINE, Scopus, and Web of Science from their inception until September 2015 for articles assessing vascular adaptations to ExT performed under hypoxic and normoxic conditions. We performed meta-analyses to determine the standardized mean difference (SMD) between the effects of ExT performed in hypoxia versus normoxia on vascular adaptations. We assessed heterogeneity among studies using I statistics and evaluated publication bias via the Begg and Mazumdar's rank correlation test and Egger's regression test. Results: After systematic review, we included 21 controlled studies, including a total of 331 individuals (mean age 19-57 years, 265 males). ExT programs primarily consisted of cycling endurance training performed in normobaric hypoxia or normoxia; duration ranged from 3 to 10 weeks. The exercise intensity was similar in relative terms in the groups trained in hypoxia and normoxia in the majority of studies (17 of 21). After data pooling, skeletal muscle capillarization ( n = 182, SMD = 0.40, 95 % confidence interval [CI] 0.10-0.70; P = 0.01) and vascular dilator function ( n = 71, SMD = 0.67, 95 % CI 0.17-1.18; P = 0.009) but not arterial stiffness ( n = 112, SMD = −0.03, 95 % CI −0.69 to 0.63; P = 0.93), were enhanced with ExT performed in hypoxia versus normoxia. We only found heterogeneity among studies assessing arterial stiffness ( I = 63 %, P = 0.02), and no publication bias was detected. Conclusion: Based on current published studies, hypoxic ExT potentiates vascular adaptations related to skeletal muscle capillarization and dilator function. These findings may contribute to establishing effective exercise programs designed to enhance vascular health. [ABSTRACT FROM AUTHOR]

Background: Gross motor competence confers health benefits, but levels in children and adolescents are low. While interventions can improve gross motor competence, it remains unclear which correlates should be targeted to ensure interventions are most effective, and for whom targeted and tailored interventions should be developed. Objective: The aim of this systematic review was to identify the potential correlates of gross motor competence in typically developing children and adolescents (aged 3-18 years) using an ecological approach. Methods: Motor competence was defined as gross motor skill competency, encompassing fundamental movement skills and motor coordination, but excluding motor fitness. Studies needed to assess a summary score of at least one aspect of motor competence (i.e., object control, locomotor, stability, or motor coordination). A structured electronic literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Six electronic databases (CINAHL Complete, ERIC, MEDLINE Complete, PsycINFO, Scopus and SPORTDiscus with Full Text) were searched from 1994 to 5 August 2014. Meta-analyses were conducted to determine the relationship between potential correlates and motor competency if at least three individual studies investigated the same correlate and also reported standardized regression coefficients. Results: A total of 59 studies were identified from 22 different countries, published between 1995 and 2014. Studies reflected the full range of age groups. The most examined correlates were biological and demographic factors. Age (increasing) was a correlate of children's motor competence. Weight status (healthy), sex (male) and socioeconomic background (higher) were consistent correlates for certain aspects of motor competence only. Physical activity and sport participation constituted the majority of investigations in the behavioral attributes and skills category. Whilst we found physical activity to be a positive correlate of skill composite and motor coordination, we also found indeterminate evidence for physical activity being a correlate of object control or locomotor skill competence. Few studies investigated cognitive, emotional and psychological factors, cultural and social factors or physical environment factors as correlates of motor competence. Conclusion: This systematic review is the first that has investigated correlates of gross motor competence in children and adolescents. A strength is that we categorized correlates according to the specific ways motor competence has been defined and operationalized (object control, motor coordination, etc.), which enables us to have an understanding of what correlates assist what types of motor competence. Indeed our findings do suggest that evidence for some correlates differs according to how motor competence is operationalized. [ABSTRACT FROM AUTHOR]

Background: Statistical methods for inferring the true magnitude of an effect from a sample should have acceptable error rates when the true effect is trivial (type I rates) or substantial (type II rates). Objective: The objective of this study was to quantify the error rates, rates of decisive (publishable) outcomes and publication bias of five inferential methods commonly used in sports medicine and science. The methods were conventional null-hypothesis significance testing [NHST] (significant and non-significant imply substantial and trivial true effects, respectively); conservative NHST (the observed magnitude is interpreted as the true magnitude only for significant effects); non-clinical magnitude-based inference [MBI] (the true magnitude is interpreted as the magnitude range of the 90 % confidence interval only for intervals not spanning substantial values of the opposite sign); clinical MBI (a possibly beneficial effect is recommended for implementation only if it is most unlikely to be harmful); and odds-ratio clinical MBI (implementation is also recommended when the odds of benefit outweigh the odds of harm, with an odds ratio >66). Methods: Simulation was used to quantify standardized mean effects in 500,000 randomized, controlled trials each for true standardized magnitudes ranging from null through marginally moderate with three sample sizes: suboptimal (10 + 10), optimal for MBI (50 + 50) and optimal for NHST (144 + 144). Results: Type I rates for non-clinical MBI were always lower than for NHST. When type I rates for clinical MBI were higher, most errors were debatable, given the probabilistic qualification of those inferences (unlikely or possibly beneficial). NHST often had unacceptable rates for either type II errors or decisive outcomes, and it had substantial publication bias with the smallest sample size, whereas MBI had no such problems. Conclusion: MBI is a trustworthy, nuanced alternative to NHST, which it outperforms in terms of the sample size, error rates, decision rates and publication bias. [ABSTRACT FROM AUTHOR]

Background: School-based intervention can contribute to the promotion of cardiorespiratory fitness (CRF) in adolescents. However, it is neces sary to systematize how intervention strategies and the methodological characteristics of studies influence the effects of CRF interventions. Objective: A meta-analysis review of school-based intervention studies aimed at increasing CRF in adolescents (10-19 years of age) was conducted. Methods: A search for studies was conducted using the Medline, Web of Science, LILACS, PsycINFO, Embase, Scopus, SPORTDiscus and Cochrane databases and the reference lists of the selected studies. The peer selection process included consideration of school-based randomized or non-randomized controlled trials with a duration ≥12 weeks published in English, Portuguese or Spanish, and with some CRF measures. The methodological quality of the studies was also assessed. The standardized mean differences (SMDs) and 95 % confidence intervals (95 % CIs) were calculated as an effect measure. Results: Forty publications of 30 interventions were included in the review, and 25 of these were meta-analysed. The effects of CRF interventions were moderate and significant (SMD = 0.68, 95 % CI 0.45-0.90), with high heterogeneity ( I = 97 %). The effect size varied significantly according to the age group, sample size, intervention environment, strategies in experimental groups, CRF priority in the study, CRF test and indicator, session length, weekly frequency, intervention duration and presentation of results by sex. Conclusion: Interventions in the school environment seem to have a positive effect on CRF among adolescents, but there is high heterogeneity between studies. Some intervention characteristics can explain better effects on CRF (e.g. exercise sessions in addition to physical education classes; primary focus on this outcome; combination of aerobic and resistance exercises; classes lasting ≥60 min; frequency of three times weekly; and intensity control). [ABSTRACT FROM AUTHOR]

Background: Balance training is considered an important means to decrease fall rates in seniors. Whether virtual reality training (VRT) might serve as an appropriate treatment strategy to improve neuromuscular fall risk parameters in comparison to alternative balance training programs (AT) is as yet unclear. Objective: To examine and classify the effects of VRT on fall-risk relevant balance performance and functional mobility compared to AT and an inactive control condition (CON) in healthy seniors. Data Sources: The literature search was conducted in five databases (CINAHL, EMBASE, ISI Web of Knowledge, PubMed, SPORTDiscus). The following search terms were used with Boolean conjunction: (exergam* OR exer-gam* OR videogam* OR video-gam* OR video-based OR computer-based OR Wii OR Nintendo OR X-box OR Kinect OR play-station OR playstation OR virtua* realit* OR dance dance revolution) AND (sport* OR train* OR exercis* OR intervent* OR balanc* OR strength OR coordina* OR motor control OR postur* OR power OR physical* OR activit* OR health* OR fall* risk OR prevent*) AND (old* OR elder* OR senior*). Study Selection: Randomized and non-randomized controlled trials applying VRT as interventions focusing on improving standing balance performance (single and double leg stance with closed and open eyes, functional reach test) and functional mobility (Berg balance scale, Timed-up and go test, Tinetti test) in healthy community-dwelling seniors of at least 60 years of age were screened for eligibility. Data Extraction: Eligibility and study quality (PEDro scale) were independently assessed by two researchers. Standardized mean differences (SMDs) served as main outcomes for the comparisons of VRT versus CON and VRT versus AT on balance performance and functional mobility indices. Statistical analyses were conducted using a random effects inverse-variance model. Results: Eighteen trials (mean PEDro score: 6 ± 2) with 619 healthy community dwellers were included. The mean age of participants was 76 ± 5 years. Meaningful effects in favor of VRT compared to CON were found for balance performance [ p < 0.001, SMD: 0.77 (95 % CI 0.45-1.09)] and functional mobility [ p = 0.004, SMD: 0.56 (95 % CI 0.25-0.78)]. Small overall effects in favor of AT compared to VRT were found for standing balance performance [ p = 0.31, SMD: −0.35 (95 % CI −1.03 to 0.32)] and functional mobility [p = 0.05, SMD: −0.44 (95 % CI: −0.87 to 0.00)]. Sensitivity analyses between 'weaker' ( n = 9, PEDro ≤5) and 'stronger' ( n = 9, PEDro ≥6) studies indicated that weaker studies showed larger effects in favor of VRT compared to CON regarding balance performance ( p < 0.001). Conclusions: Although slightly less effective than AT, VRT-based balance training is an acceptable method for improving balance performance as well as functional mobility outcomes in healthy community dwellers. VRT might serve as an attractive complementary training approach for the elderly. However, more high-quality research is needed in order to derive valid VRT recommendations compared to both AT and CON. [ABSTRACT FROM AUTHOR]

Background: Whilst previous meta-analyses have demonstrated that control group responses (CGRs) can negatively influence antidepressant efficacy, no such meta-analysis exists in exercise randomised controlled trials (RCTs). Objective: The aim of this study was to conduct a systematic review and meta-analysis investigating CGRs and predictors in control groups of exercise RCTs among adults with depression. Methods: Three authors acquired RCTs from a previous Cochrane review (2013) and conducted updated searches of major databases from January 2013 to August 2015. We included exercise RCTs that (1) involved adults with major depressive disorder (MDD) or depressive symptoms; (2) measured depressive symptoms pre- and post-intervention using a validated measure [e.g. Hamilton Depression Scale (HAM-D)]; and (3) included a non-active control group. A random effects meta-analysis calculating the standardised mean difference (SMD) together with 95 % confidence intervals (CIs) was employed to determine CGR. Results: Across 41 studies, 1122 adults with depression were included [mean (SD) age 50 (18) years, 63 % female]. A large CGR of improved depressive symptoms was evident across all studies (SMD −0.920, 95 % CI −1.11 to −0.729). CGRs were elevated across all subgroup analyses, including high quality studies ( n = 11, SMD −1.430, 95 % CI −1.771 to −1.090) and MDD participants ( n = 18, SMD −1.248, 95 % CI = −1.585 to −0.911). The CGR equated to an improvement of −7.5 points on the HAM-D (95 % CI −10.30 to −4.89). In MDD participants, increasing age moderated a smaller CGR, while the percentage of drop-outs, baseline depressive symptoms and a longer control group duration moderated a larger CGR (i.e. improvement) ( p < 0.05). Conclusion: In order to demonstrate effectiveness, exercise has to overcome a powerful CGR of approximately double that reported for antidepressant RCTS. [ABSTRACT FROM AUTHOR]

Background: It remains unclear whether repetitions leading to failure (failure training) or not leading to failure (non-failure training) lead to superior muscular strength gains during resistance exercise. Failure training may provide the stimulus needed to enhance muscular strength development. However, it is argued that non-failure training leads to similar increases in muscular strength without the need for high levels of discomfort and physical effort, which are associated with failure training. Objective: We conducted a systematic review and meta-analysis to examine the effect of failure versus non-failure training on muscular strength. Methods: Five electronic databases were searched using terms related to failure and non-failure training. Studies were deemed eligible for inclusion if they met the following criteria: (1) randomised and non-randomised studies; (2) resistance training intervention where repetitions were performed to failure; (3) a non-failure comparison group; (4) resistance training interventions with a total of ≥3 exercise sessions; and (5) muscular strength assessment pre- and post-training. Random-effects meta-analyses were performed to pool the results of the included studies and generate a weighted mean effect size (ES). Results: Eight studies were included in the meta-analysis (combined studies). Training volume was controlled in four studies (volume controlled), while the remaining four studies did not control for training volume (volume uncontrolled). Non-failure training resulted in a 0.6-1.3 % greater strength increase than failure training. A small pooled effect favouring non-failure training was found (ES = 0.34; p = 0.02). Significant small pooled effects on muscular strength were also found for non-failure versus failure training with compound exercises (ES = 0.37-0.38; p = 0.03) and trained participants (ES = 0.37; p = 0.049). A slightly larger pooled effect favouring non-failure training was observed when volume-uncontrolled studies were included (ES = 0.41; p = 0.047). No significant effect was found for the volume-controlled studies, although there was a trend favouring non-failure training. The methodological quality of the included studies in the review was found to be moderate. Exercise compliance was high for the studies where this was reported ( n = 5), although limited information on adverse events was provided. Conclusion: Overall, the results suggest that despite statistically significant effects on muscular strength being found for non-failure compared with failure training, the small percentage of improvement shown for non-failure training is unlikely to be meaningful. Therefore, it appears that similar increases in muscular strength can be achieved with failure and non-failure training. Furthermore, it seems unnecessary to perform failure training to maximise muscular strength; however, if incorporated into a programme, training to failure should be performed sparingly to limit the risks of injuries and overtraining. [ABSTRACT FROM AUTHOR]

Background: The effects of swimming on bone mineral density (BMD) have been studied by several researchers, with inconsistent results. Aim: This meta-analysis aims to determine whether systematic swimming training may influence BMD during childhood and adolescence. Methods: A systematic search was performed in PubMed, SPORTDiscus and ClinicalTrials.gov from the earliest possible year to March 2015, with data extraction and quality assessment performed independently by two researchers following the PRISMA methodology. Swimmers were compared to sedentary controls and to athletes performing highly osteogenic sports. Therefore, a total of two meta-analyses were developed. Results: Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to sedentary controls and lower than other high-impact athletes. Femoral neck and lumbar spine BMD differences between swimmers and sedentary controls and between swimmers and athletes practicing osteogenic sports appeared to increase with age and favored the non-swimming groups. There were no differences by sex. Conclusion: While swimming is associated with several health benefits, it does not appear to be an effective sport for improving BMD. Swimmers might be in need of additional osteogenic exercises for increasing BMD values. [ABSTRACT FROM AUTHOR]

Background: Resistance training (RT) has been investigated as a potential intervention strategy for improving muscle function, but the effects on lower-extremity muscle power in middle-aged and older adults have not been systematically reviewed. Objective: The aim of this meta-analysis is to provide a quantitative estimate of the effect of RT on lower-extremity muscle power in middle-aged and older adults and to examine independent moderators of this relationship. Methods: Randomized controlled trials that examined the effects of RT on either leg press (LP) or knee extension (KE) muscle power in adults aged ≥50 years were included. Data were aggregated with meta-analytic techniques, and multi-level modeling was used to adjust for nesting effects. A total of 52 effects from 12 randomized controlled trials were analyzed with a random-effects model to estimate the effect of RT on lower-extremity muscle power. A multiple-regression analysis was conducted to examine independent moderators of the mean effect. Results: The adjusted aggregated results from all studies indicate that RT has a small-to-moderate effect on lower-extremity muscle power (Hedges' d = 0.34, 95 % confidence interval [CI] 0.25-0.43), which translated to 54.90 watts (95 % CI 40.37-69.43). Meta-regression analyses indicated that high-velocity RT was superior to traditional RT (Δ = 0.62 vs. 0.20, respectively) for increasing lower-extremity muscle power. In addition, training volume significantly moderated the effect of RT on muscle power. Conclusion: The findings from this meta-analysis indicate that RT is an efficacious intervention strategy for improving LP and KE muscle power in adults aged ≥50 years. Training mode and volume independently moderate the effect of RT on lower-extremity muscle power, and should be considered when prescribing RT exercise for middle-aged and older adults. [ABSTRACT FROM AUTHOR]

Background: Depression symptom severity and cardiorespiratory fitness (CRF) are significant predictors of mortality and disability. However, the relationship between the two is unclear. Objective: This meta-analysis assessed the relationship between depression symptom severity and CRF in healthy and depressed adults (aged 18 years and over). Search Methods: The PubMed, Cochrane Library, Google Scholar and ProQuest databases were browsed for relevant English-language studies published from January 2000 to August 2014. Selection Criteria: Studies reporting a correlation between a depression scale and maximum oxygen consumption ( VO), as well as studies from the data of which such a correlation could be calculated, were included in this analysis. Data Analysis: Correlation coefficients (CCs) were converted to Fisher's z values, and the analysis was performed using a random-effects model. Then, summary effects and 95 % confidence intervals (CIs) were converted back to CCs. Results: Sixteen studies (totalling 4039 participants) were included in this analysis. A modest correlation between depression symptom severity and CRF was found (CC −0.16, 95 % CI −0.21 to −0.10), appearing stronger in male participants (CC − 0.22, 95 % CI −0.26 to −0.18) than in female participants (CC −0.12, 95 % CI −0.19 to −0.05; p = 0.01). There was no difference in the summary effect between healthy and depressed adults ( p = 0.43). Heterogeneity was moderate ( I = 33 %; p = 0.09). Conclusions: Depression symptom severity is inversely correlated with CRF, and this correlation is stronger in men than in women. Clinical and prognostic implications of the correlation are discussed. These findings should stimulate further research on the effects of treating one variable on the other. [ABSTRACT FROM AUTHOR]

Background: Although post-activation potentiation (PAP) has been extensively examined following the completion of a conditioning activity (CA), the precise effects on subsequent jump, sprint, throw, and upper-body ballistic performances and the factors modulating these effects have yet to be determined. Moreover, weaker and stronger individuals seem to exhibit different PAP responses; however, how they respond to the different components of a strength-power-potentiation complex remains to be elucidated. Objectives: This meta-analysis determined (1) the effect of performing a CA on subsequent jump, sprint, throw, and upper-body ballistic performances; (2) the influence of different types of CA, squat depths during the CA, rest intervals, volumes of CA, and loads during the CA on PAP; and (3) how individuals of different strength levels respond to these various strength-power-potentiation complex components. Methods: A computerized search was conducted in ADONIS, ERIC, SPORTDiscus, EBSCOhost, Google Scholar, MEDLINE, and PubMed databases up to March 2015. The analysis comprised 47 studies and 135 groups of participants for a total of 1954 participants. Results: The PAP effect is small for jump (effect size [ES] = 0.29), throw (ES = 0.26), and upper-body ballistic (ES = 0.23) performance activities, and moderate for sprint (ES = 0.51) performance activity. A larger PAP effect is observed among stronger individuals and those with more experience in resistance training. Plyometric (ES = 0.47) CAs induce a slightly larger PAP effect than traditional high-intensity (ES = 0.41), traditional moderate-intensity (ES = 0.19), and maximal isometric (ES = -0.09) CAs, and a greater effect after shallower (ES = 0.58) versus deeper (ES = 0.25) squat CAs, longer (ES = 0.44 and 0.49) versus shorter (ES = 0.17) recovery intervals, multiple- (ES = 0.69) versus single- (ES = 0.24) set CAs, and repetition maximum (RM) (ES = 0.51) versus sub-maximal (ES = 0.34) loads during the CA. It is noteworthy that a greater PAP effect can be realized earlier after a plyometric CA than with traditional high- and moderate-intensity CAs. Additionally, shorter recovery intervals, single-set CAs, and RM CAs are more effective at inducing PAP in stronger individuals, while weaker individuals respond better to longer recovery intervals, multiple-set CAs, and sub-maximal CAs. Finally, both weaker and stronger individuals express greater PAP after shallower squat CAs. Conclusions: Performing a CA elicits small PAP effects for jump, throw, and upper-body ballistic performance activities, and a moderate effect for sprint performance activity. The level of potentiation is dependent on the individual's level of strength and resistance training experience, the type of CA, the depth of the squat when this exercise is employed to elicit PAP, the rest period between the CA and subsequent performance, the number of set(s) of the CA, and the type of load used during the CA. Finally, some components of the strength-power-potentiation complex modulate the PAP response of weaker and stronger individuals in a different way. [ABSTRACT FROM AUTHOR]

Background: Dietary supplements (DSs) are commercially available products consumed as an addition to the usual diet and are frequently ingested by athletes. Objective: Our objective was to examine the prevalence of DS use by athletes. Data Sources: PubMed, Ovid MEDLINE, OVID Healthstar, and Cumulative Index to Nursing and Allied Health were searched for original research articles published up to August 2014. Search terms included specific sports, specific DSs, and other terms. Study Selection: Studies were selected if they were written in English, involved athletes, and provided a quantitative assessment of the proportion of athletes using specific DSs. Summary Measure: Percent of athletes using specific DSs. Synthesis of Data: Methodological quality of studies was assessed by three reviewers using an 8-point scale that included evaluations for sampling methods, sampling frame, sample size, measurement tools, bias, response rate, statistical presentation, and description of the participant sample. Where there were at least two investigations, meta-analysis was performed to obtain summary (pooled) prevalence estimates (SPEs) on (1) DS use prevalence by sport and sex, (2) DS use prevalence by elite versus non-elite athletic status, and (3) specific DS prevalence for all athletic groups combined. Meta-analyses included evaluations of homogeneity and publication bias. Results: A total of 159 unique studies met the review criteria. Methodological quality was generally low with an average ± standard deviation of 43 ± 16 % of available rating points. There was low homogeneity for SPEs when compiled by sport, athletic status, and/or specific DSs. Contributing to the lack of homogeneity were differences in studies' objectives and types of assessments used (e.g., dietary surveys, interviews, questionnaires). Despite these limitations, the data generally indicated that elite athletes used DSs much more than their non-elite counterparts. For most DSs, use prevalence was similar for men and women except that a larger proportion of women used iron while a larger proportion of men used vitamin E, protein, and creatine. No consistent change in use over time was observed because even the earliest investigations showed relatively high use prevalence. Conclusion: It was difficult to generalize regarding DS use by athletes because of the lack of homogeneity among studies. Nonetheless, the data suggested that elite athletes used dietary supplements far more than their non-elite counterparts; use was similar for men and women with a few exceptions; use appeared to change little over time; and a larger proportion of athletes used DSs compared with the general US population. Improvements in study methodology should be considered in future studies especially (1) defining DSs for participants; (2) querying for very specific DSs; (3) using a variety of reporting timeframes (e.g., daily, 2-6 times/week, 1 time/week and <1 time/week); (4) reporting the sampling frame, number of individuals solicited, and number responding; (5) reporting characteristics of volunteers (and non-volunteers, if available); and (6) using similar methods on several occasions to examine possible temporal trends among athletes. [ABSTRACT FROM AUTHOR]

Background: Soccer is the most popular sport worldwide, with a long history and currently more than 500 million active participants, of whom 300 million are registered football club members. On the basis of scientific findings showing positive fitness and health effects of recreational soccer, FIFA (Fédération Internationale de Football Association) introduced the slogan 'Playing football for 45 min twice a week-best prevention of non-communicable diseases' in 2010. Objective: The objective of this paper was to perform a systematic review and meta-analysis of the literature to determine the effects of recreational soccer on maximal oxygen uptake ( $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ ). Methods: Six electronic databases (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) were searched for original research articles. A manual search was performed to cover the areas of recreational soccer, recreational physical activity, recreational small-sided games and $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ using the following key terms, either singly or in combination: recreational small-sided games, recreational football, recreational soccer, street football, street soccer, effect, maximal oxygen uptake, peak oxygen uptake, cardiorespiratory fitness, $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ . The inclusion criteria were divided into four sections: type of study, type of participants, type of interventions and type of outcome measures. Probabilistic magnitude-based inferences for meta-analysed effects were based on standardised thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations for baseline fitness. Results: Seventeen studies met the inclusion criteria and were included in the systematic review and meta-analysis. Mean differences showed that $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ increased by 3.51 mL/kg/min (95 % CI 3.07-4.15) over a recreational soccer training programme in comparison with other training models. The meta-analysed effects of recreational soccer on $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ compared with the controls of no exercise, continuous running and strength training were most likely largely beneficial [effect size (ES) = 1.46; 95 % confidence interval (CI) 0.91, 2.01; I = 88.35 %], most likely moderately beneficial (ES = 0.68; 95 % CI 0.06, 1.29; I = 69.13 %) and most likely moderately beneficial (ES = 1.08; 95 % CI −0.25, 2.42; I = 71.06 %), respectively. In men and women, the meta-analysed effect was most likely largely beneficial for men (ES = 1.22) and most likely moderately beneficial for women (ES = 0.96) compared with the controls. After 12 weeks of recreational soccer with an intensity of 78-84 % maximal heart rate (HR), healthy untrained men improved their $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ by 8-13 %, while untrained elderly participants improved their $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ by 15-18 %. Soccer training for 12-70 weeks in healthy women resulted in an improvement in $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ of 5-16 %. Significant improvements in $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ have been observed in patients with diabetes mellitus, hypertension and prostate cancer. Conclusion: Recreational soccer produces large improvements in $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ compared to strength training and no exercise, regardless of the age, sex and health status of the participants. Furthermore, recreational soccer is better than continuous endurance running, albeit the additional effect is moderate. This kind of physical activity has great potential for enhancing aerobic fitness, and for preventing and treating non-communicable diseases, and is ideal for addressing lack of motivation, a key component in physical (in)activity. [ABSTRACT FROM AUTHOR]

Background: It is recognized that low oestrogen status impairs the skeletal response to mechanical loading in elderly women; therefore, oestrogen administration is expected to increase the osteogenic response to mechanical strain. Objectives: This meta-analysis aimed to evaluate the combined effects of hormone replacement therapy (HRT) and exercise on femoral neck and lumbar spine bone mineral density (BMD) in postmenopausal women, in comparison with the effects of exercise-only intervention. Methods: A systematic literature search was conducted in PubMed, Embase, SPORTDiscus and ProQuest up to May 1, 2014, to ascertain the influence of oestrogen administration and exercise on BMD in postmenopausal women. The study quality and potential publication bias of the included trials were evaluated. The primary end point was the change in BMD from baseline to follow-up. The effect sizes were estimated in terms of the standardized mean difference (SMD). Subgroup analysis was conducted on the basis of exercise categories. Results: Six studies with a total of 764 postmenopausal women (aged between 51.8 ± 2.9 and 68.0 ± 3.0 years) met the inclusion criteria. The included studies had low and high levels of heterogeneity of hip outcomes ( I = 0.0 %) and spine outcomes ( I = 80.8 %), respectively. Fixed- and random-effects models were used for calculating the effect size estimates. The pooled effect sizes associated with the combined interventions of HRT and exercise were significant for femoral neck BMD (SMD 0.220, 95 % confidence interval [CI] 0.011-0.429, p = 0.039) and lumbar spine BMD (SMD 0.729, 95 % CI 0.186-1.273, p = 0.009) in comparison with the exercise-only intervention. The mixed loading exercise programmes were sensitive to HRT in preventing postmenopausal bone loss in the spine (SMD 1.073, 95 % CI 0.140-2.005, p = 0.024) in comparison with single-mode exercise. Conclusions: Our findings indicate that oestrogen treatment significantly increases the skeletal response to exercise training in both the hips and the spine in postmenopausal women, which implies that the combination of oestrogen administration and exercise may generate greater effects. [ABSTRACT FROM AUTHOR]

Background: How hypohydration impacts non-bodyweight (BW)-dependent muscle performance and vertical jumping ability remains to be determined using meta-analytic procedures. Objectives: Our objective was to determine the impact of hypohydration on muscle endurance, strength, anaerobic power and capacity and vertical jumping ability using a meta-analytic approach. Data sources: Studies were located using database searches and cross-referencing. Synthesis methods: Effect summaries were obtained using random-effects models; method of moments mixed-effects analysis-of-variance-like procedures were used to determine differences between groups; and restricted maximum likelihood random-effects meta-regressions were performed to determine relationships between variables, impact of confounders, and interaction effects. Results: A total of 28 manuscripts met the inclusion criteria, producing six (upper body muscle endurance), ten (lower body muscle endurance), 14 (upper body muscle strength), 25 (lower body muscle strength), nine (muscle anaerobic power), nine (muscle anaerobic capacity), and 12 (vertical jumping ability) effect estimates. Hypohydration impaired overall muscle endurance by 8.3 ± 2.3 % ( P < 0.05), with no significant difference between upper body (−8.4 ± 3.3 %) and lower body (−8.2 ± 3.2 %). As a whole, muscle strength fell by 5.5 ± 1.0 % ( P < 0.05) with hypohydration; the difference between lower (−3.7 ± 1.8 %) and upper (−6.2 ± 1.1 %) body was non-significant. Anaerobic power (−5.8 ± 2.3 %) was significantly altered with hypohydration, but anaerobic capacity (−3.5 ± 2.3 %) and vertical jumping ability (0.9 ± 0.7 %) were not. No significant correlations were observed between the changes in any of the muscle performance variables or vertical jumping ability and the changes in hypohydration level. Using an active procedure to dehydrate participants decreased muscle performance by an additional 5.4 ± 1.9 % (2.76-fold) ( P = 0.02) compared with using a passive dehydration procedure. Trained individuals demonstrated a 3.3 ± 1.7 % (1.76-fold) ( P = 0.06) lesser decrease in muscle performance with hypohydration than did untrained individuals. Conclusion: Hypohydration, or factors associated with dehydration, are likely to be associated with practically important decrements in muscle endurance, strength, and anaerobic power and capacity. However, their impact on non-BW-dependent muscle performance is substantially mitigated in trained individuals or when hypohydration is induced passively. Conversely, it is possible that body water loss (~3 % BW) may improve performance in BW-dependent tasks such as vertical jumping ability. [ABSTRACT FROM AUTHOR]

Background: Gastric emptying (GE) could influence exercise-induced changes in appetite and energy intake. GE also could contribute to changes in gastric symptoms and the availability of nutrients during exercise, which will subsequently affect performance. Objective: The objective of this review was to determine the effects of acute exercise on GE using a systematic review and meta-analysis. The most common parameters to determine GE were selected, consisting of half-emptying time and volume emptied. Oral-caecal transit time (OCTT) was also examined. Data Sources: Research databases (PubMed, Scopus, Google Scholar, EBSCOhost, SPORTDiscus) were searched through November 2013 for original studies, abstracts, theses and dissertations that examined the influence of acute exercise on GE. Study Selection: Studies were included if they evaluated GE or OCTT during and/or after exercise and involved a resting control trial. Study Appraisal and Synthesis: Initially, 195 studies were identified. After evaluation of study characteristics and quality and validity, data from 20 studies (35 trials) involving 221 participants (157 men; 52 women; 12 unknown) were extracted for meta-analysis. Random-effects meta-analyses were utilised for the three main outcome variables, and effect sizes (ES) are reported as Hedge's g due to numerous small sample sizes. Results: Random-effects modelling revealed non-significant and small/null main effect sizes for volume emptied (ES = 0.195; 95 % CI −0.25 to 0.64), half-time (ES = −0.109, 95 % CI −0.66 to 0.44) and OCTT (ES = 0.089; 95 % CI −0.64 to 0.82). All analyses exhibited significant heterogeneity and numerous variables moderated the results. There was a dose response of exercise intensity; at lower intensities GE was faster, and at high exercise intensities GE was slower. Walking was associated with faster GE and cycling with slower GE. Greater volume of meal/fluid ingested, higher osmolality of beverage and longer exercise duration were also associated with slower GE with exercise. Limitations: The major limitation is that the majority of studies utilised a liquid bolus administered pre-exercise to determine GE; the relationship to post-exercise appetite and energy intake remains unknown. Study populations were also generally active or trained individuals. Furthermore, our review was limited to English language studies and studies that utilised resting control conditions. Conclusions: These results suggest that exercise intensity, mode, duration and the nature of meal/fluid ingested all influence GE during and after acute exercise. The relationship of GE parameters with appetite regulation after exercise remains largely unexplored. Further integrative studies combining GE and alterations in gut hormones, as well as in populations such as overweight and obese individuals are needed. [ABSTRACT FROM AUTHOR]

Background: The acute impact of different types of physical activity on glycemic control in type 1 diabetes has not been well quantified. Objectives: Our objective was to estimate the rate of change (RoC) in glucose concentration induced acutely during the performance of structured exercise and at recovery in subjects with type 1 diabetes. Methods: We searched for original articles in the PubMed, MEDLINE, Scopus, and Cochrane databases. Search terms included type 1 diabetes, blood glucose, physical activity, and exercise. Eligible studies (randomized controlled trials and non-randomized experiments) encompassed controlled physical activity sessions (continuous moderate [CONT], intermittent high intensity [IHE], resistance [RESIST], and/or a resting reference [REST]) and reported excursions in glucose concentration during exercise and after its cessation. Data were extracted by graph digitization to compute two RoC measures from population profiles: RoC during exercise and RoC in recovery. Results: Ten eligible studies were found from 540 publications. Meta-analyses of exercise modalities versus rest yielded the following: RoC −4.43 mmol/L h ( p < 0.00001, 95 % confidence interval [CI] −6.06 to −2.79) and RoC +0.70 mmol/L h ( p = 0.46, 95 % CI −1.14 to +2.54) for CONT vs. REST; RoC −5.25 mmol/L·h ( p < 0.00001, 95 % CI −7.02 to −3.48) and RoC +0.72 mmol/L h ( p = 0.71, 95 % CI −3.10 to +4.54) for IHE vs. REST; RoC −2.61 mmol/L h ( p = 0.30, 95 % CI −7.55 to +2.34) and RoC −0.02 mmol/L h ( p = 1.00, 95 % CI −7.58 to +7.53) for RESIST vs. REST. Conclusions: Novel RoC magnitudes RoC, RoC reflected rapid decays of glycemia during CONT exercise and gradual recoveries immediately afterwards. RESIST showed more constrained decays, whereas discrepancies were found for IHE. [ABSTRACT FROM AUTHOR]

Background: Maximizing the hypertrophic response to resistance training (RT) is thought to be best achieved by proper manipulation of exercise program variables including exercise selection, exercise order, length of rest intervals, intensity of maximal load, and training volume. An often overlooked variable that also may impact muscle growth is repetition duration. Duration amounts to the sum total of the concentric, eccentric, and isometric components of a repetition, and is predicated on the tempo at which the repetition is performed. Objective: We conducted a systematic review and meta-analysis to determine whether alterations in repetition duration can amplify the hypertrophic response to RT. Methods: Studies were deemed eligible for inclusion if they met the following criteria: (1) were an experimental trial published in an English-language refereed journal; (2) directly compared different training tempos in dynamic exercise using both concentric and eccentric repetitions; (3) measured morphologic changes via biopsy, imaging, and/or densitometry; (4) had a minimum duration of 6 weeks; (5) carried out training to muscle failure, defined as the inability to complete another concentric repetition while maintaining proper form; and (6) used human subjects who did not have a chronic disease or injury. A total of eight studies were identified that investigated repetition duration in accordance with the criteria outlined. Results: Results indicate that hypertrophic outcomes are similar when training with repetition durations ranging from 0.5 to 8 s. Conclusions: From a practical standpoint it would seem that a fairly wide range of repetition durations can be employed if the primary goal is to maximize muscle growth. Findings suggest that training at volitionally very slow durations (>10s per repetition) is inferior from a hypertrophy standpoint, although a lack of controlled studies on the topic makes it difficult to draw definitive conclusions. [ABSTRACT FROM AUTHOR]