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Introduction: Low cardiorespiratory fitness (CRF) increases the risk of cardiovascular disease by up to eightfold and is one of the strongest predictors of mortality. Some studies demonstrate impaired CRF in people living with type 1 and type 2 diabetes compared with those without diabetes, whereas others demonstrate no diabetes-associated impairment in CRF. Purpose: We aimed to determine whether diabetes can influence CRF and, if so, identify clinical associations underlying diabetes-associated exercise impairments. Methods: Sixty-eight studies were included in the quantitative analysis. Standardized mean difference (SMD) was calculated and meta-analyses and meta-regressions were performed by using a random-effects model. Results: Diabetes is associated with a large negative effect on CRF (SMD = -0.80, P < 0.001)--an effect that is partially mitigated, but still significant, in those with high physical activity levels (SMD = -0.50, P = 0.007). A sedentary lifestyle (SMD = -0.83, P = 0.007) and the presence of clinical complications related to diabetes (SMD = -1.66, P < 0.001) predict a greater magnitude of CRF reduction in people with diabetes compared with controls without diabetes. Both type 1 diabetes and type 2 diabetes are independently associated with impaired CRF compared with controls without diabetes; however, the effect is significantly greater in those type 2 diabetes (SMD = -0.97, P < 0.001).Meta-regression analysis demonstrates the effects of diabetes on CRF are primarily associated with HbA1c levels for type 1 diabetes (B = -0.07, P < 0.001) and body mass index for type 2 diabetes (B = -0.17, P = 0.005). Conclusions: These data demonstrate a negative influence of diabetes on the key risk factor of low CRF and provide critical insight into specific clinical markers of low CRF associated with diabetes. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of low- and high-volume speed endurance training (SET), with a reduced training volume, on sprint ability, short- and long-term exercise capacity, muscle mitochondrial properties, ion transport proteins, and maximal enzyme activity in highly trained athletes. Methods: Highly trained male cyclists (maximal oxygen consumption (...): 68.3 ± 5.0 mL⋅min-1⋅kg-1, n = 24) completed 6 wk of either low (SET-L; 6 x 30-s intervals, n = 8) or high (SET-H; 12 x 30-s intervals, n = 8) volume SET twice per week with a 30% reduction in training volume. A control group (CON; n = 8) maintained their training. Exercise performance was evaluated by i) 6-s sprinting, ii) a 4-min time trial, and iii) a 60-min preload at 60% ... followed by a 20-min time trial. A biopsy of m. vastus lateralis was collected before and after the training intervention. Results: In SET-L, 4-min time trial performance was improved (P < 0.05) by 3.8%, with no change in SET-H and CON. Sprint ability, prolonged endurance exercise capacity, ..., muscle mitochondrial respiratory capacity, maximal citrate synthase activity, fiber type--specific mitochondrial proteins (complexes I-V), and phosphofructokinase (PFK) content did not change in any of the groups. In SET-H, maximal activity of muscle PFK and abundance of Na+-K+ pump-subunit α1, α2, β1, and phospholemman (FXYD1) were 20%, 50%, 19%, 24%, and 42% higher (P < 0.05), respectively after compared with before the intervention, with no changes in SET-L or CON. Conclusions: Low SET volume combined with a reduced aerobic low- and moderate-intensity training volume does improve short-duration intense exercise performance and maintain sprinting ability, ..., endurance exercise performance, and muscle oxidative capacity, whereas, high volume of SET seems necessary to upregulate muscle ion transporter content and maximal PFK activity in highly trained cyclists. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the effects of a 7-d high-intensity interval training shock microcycle (HIIT-SM) with or without additional low-intensity training (LIT) on aerobic fitness and endurance performance compared with a control group (CG). Methods: Thirty-three endurance-trained athletes (7 women, 26 men, mean ± SD: age, 30.2 ± 6.9 yr;maximal oxygen uptake (VO2max), 59.8 ± 4.9 mL·min-1·kg-1) performed exercise testing at T1 and were randomly assigned to one of three groups: i) HSM, 10 running-based HIIT sessions (5 × 4 min at 90%-95% maximal heart rate) over 7 d; ii)HSM+ LIT, equal toHSMwith additional 30 min of LIT after each HIIT; iii) CG, regular training. Exercise testing was repeated 3 d (T2), 7 d (T3), and 14 d (T4) after the intervention. A 5-km time trial (TT5km) was performed 3-4 d before T1 and 10-11 d after the intervention. Data were analyzed by two-way repeated-measures ANOVA. Results: No interaction effect was found for VO2max (P = 0.170, pη² = 0.09), peak power output (P = 0.734, pη² = 0.04), and work economy (P = 0.804, pη² = 0.03). There was an interaction for velocity at lactate threshold (P = 0.006, pη² = 0.18) with increased velocity in HSM at T2 (3.2%, P = 0.030), T3 (4%, P = 0.006), T4 (4%, P = 0.003), as well as in HSM + LIT for T2 (3.2%, P = 0.011), whereas CG showed no change. There was an interaction for TT5km (P = 0.044, pη² = 0.19), with HSM improving 2.7% (P = 0.003) and HSM + LIT 2.3% (P = 0.010), whereas CG was, on average, -0.3% (P = 0.821) slower. Conclusions: HIIT-SM with or without additional LIT has negligible effects on VO2max but improves other key endurance variables in endurance-trained athletes. No superiority of either intervention group was demonstrated. Therefore, additional LIT during HIIT-SM is not beneficial. [ABSTRACT FROM AUTHOR]

Purpose: To understand athletic performance before and after puberty, this study determined 1) the age at which the sex difference increases among elite youth track and field athletes for running and jumping events, and 2) whether there is a sex difference in performance before ages associated with puberty among elite youth athletes. Methods: Track and field records of elite USmale and female youth (7-18 yr) across 3 yr (2019, 2021, and 2022) were collected from an online database (athletic.net). The top 50 performances were recorded for 100-, 200-, 400-, and 800-m track running, long jump, and high jump. Results:Males ran faster than females at every age in the 100, 200, 400 and 800 m (P < 0.001). When combining all running events, the sex difference (%) was 4.0% ± 1.7% between 7 and 12 yr and increased to 6.3% ± 1.1% at 13 yr and 12.6% ± 1.8% at 18 yr (P < 0.001). Similarly, males jumped higher and farther than females at every age (P < 0.001). For long jump, the sex differencewas 6.8%± 2.8% between 7 and 12 yr, increasing to 8.5% ± 1.7% at 13 yr and 22.7% ± 1.4% at 18 yr (P < 0.001). For high jump, the sex difference was 5.3% ± 5.2% between 7 and 12 yr, increasing to 12.4% ± 2.9% at 15 yr and 18.4% ± 2.04% at 18 yr (P < 0.001). Conclusions: Before 12 yr of age in elite youth track and field athletes, there was a consistent and significant sex difference of ~5%, such that males ran faster and jumped higher and farther than females. The magnitude of the sex difference in performance increased markedly at 12-13 yr for running and long jump and 14 yr for high jump and thus was more pronounced after ages associated with puberty. [ABSTRACT FROM AUTHOR]

Background and Purpose: The international Consensus on Therapeutic Exercise aNd Training (i-CONTENT) tool is a new instrument developed to evaluate the therapeutic quality of exercise interventions. Home-based exercise has been shown to improve physical fitness in older adults, but its effects may be influenced by therapeutic quality. The purpose of this systematic review was to describe the therapeutic quality of home-based exercise interventions for community-dwelling older adults and examine the relationship between therapeutic quality and changes in physical fitness. Methods: Six electronic databases and 2 clinical trial registries were searched for randomized controlled trials investigating the effects of home-based exercise on physical fitness in community- dwelling older adults (≥60 years). Therapeutic quality was evaluated using the i-CONTENT tool for items of patient selection, type of exercise, safety, type/timing of outcomes, exercise dose, and adherence. International Consensus on Therapeutic Exercise aNd Training items were used to explain heterogeneity in meta-regression analyses. Risk of bias, certainty of evidence and credibility of analyses were assessed. Results: Thirty-six trials (n = 6157 participants) were identified. Most studies (≥66.7%) had high or probably high therapeutic quality for i-CONTENT items, except exercise dose (47.2%) and adherence (16.7%). Interventions improved upper- (N = 20 trials; standardized mean difference [SMD] = 0.39; 95% CI, 0.13-0.64; low certainty of evidence) and lower-body strength (N = 28; SMD = 0.42; 95% CI, 0.08-0.77; very low certainty), and aerobic fitness (N = 8; SMD = 0.42; 95% CI, 0.08-0.77; very low certainty). For exercise dose, low- or probably low-quality studies negatively influenced effects on upper- (estimated β = -.48; P = .049; moderate credibility) and lower-body strength (estimated β = -.77; P = .048; moderate credibility). For adherence, low- or probably low-quality studies negatively influenced effects on aerobic fitness (estimated β = -.97; P = .02; low credibility). Conclusions: Home-based exercise may improve upper- and lower-body strength, as well as aerobic fitness in older adults. However, the effectiveness of interventions is affected by inadequate dosing of exercise programs and adherence issues. Physical therapists should have the best available evidence to support their clinical decision making, especially when designing and monitoring home programs. [ABSTRACT FROM AUTHOR]

This controlled intervention study examined the effects of low-intensity rowing with blood flow restriction (BFR) on maximal oxygen uptake (...O2max), peak power output during ramp testing (PPO), and 2000-m time trial performance (P2k). Eleven, highly elite, male rowers (22.1 ± 1.6 years; 92.6 ± 3.8 kg; 1.93 ± 0.04 m; 7.9. ± 2.2 years rowing experience; 20.4 ± 2.0 h⋅w-1 training volume; 11.9 ± 1.1 session per week) trained 5 weeks without BFR (Base) followed by a 5-week BFR intervention period. BFR of the lower limb was applied through customized elastic wraps. BFR took place 3 times a week (accumulated net pBFR: 60 min⋅wk-1; occlusion per session: 2 times 10 min⋅session-1) and was used exclusively at low intensities (<2 mmol⋅L-1). ...O2max, PPO, and P2k were examined before, between, and after both intervention periods. Bayesian's credible intervals revealed relevantly increased ...O2max +0.30 L⋅min-1 (95% credible interval: +0.00 to +0.61 L⋅min-1) adaptations through BFR. By contrast, PPO +14 W (-6to+34 W and P2k -5W(-14 to +3 W) were not noticeably affected by the BFR intervention. This study revealed that 15 sessions of BFR application with a cumulative total BFR load of 5 h over a 5-week macrocycle increased ...O2max remarkably. Thus, pBFR might serve as a promising tool to improve aerobic capacity in highly trained elite rowers. [ABSTRACT FROM AUTHOR]

Drawing from the general population for its recruiting needs, police departments often employ academy curricula to improve a recruit's fitness so they can perform occupational tasks. Recently, obesity and physical inactivity have increased in the general population, potentially influencing the health and fitness of incoming recruits. This study involved a retrospective, cross-sectional analysis of health and fitness data of police recruits. Data from 1 police department in southeastern United States were analyzed at 4 specific time points, splitting the recruits into natural immerging groups; 2003 (n = 93), 2006 (n = 137), 2009 (n = 74), and 2019 (n = 242). Health and fitness data for all recruits included age, height, body mass, and body mass index (BMI); systolic and diastolic blood pressure (BP); sit-and-reach; combined grip strength; push-ups and sit-ups completed in 60 seconds; physical ability test time; and 2.4-km run time. Several univariate analyses, with sex and age as covariates (analyses of covariance), and a Bonferroni's post hoc, determined whether there were significant between-group differences. Effect sizes (d) were also calculated. Key results demonstrated that 2019 recruits were heavier than the recruits in 2006 and 2009 (p ≤0.032; d = 0.14-0.38); had a greater BMI (p ≤ 0.028; d = 0.24-0.75) and systolic BP (p < 0.001; d = 0.47-0.65), and lesser sit-and-reach distance (p ≤ 0.020; d = 0.26-0.46), than all recruit groups; completed fewer sit-up repetitions than the recruits in 2006 and 2009 (p≤ 0.025; d = 0.42-0.48); and were slower in the 2.4-km run than the recruits in 2006 (p = 0.009; d = 0.36). Police training staff may need to address lesser health (BMI, BP) and fitness (hamstring flexibility, abdominal endurance, aerobic fitness) in incoming recruits. [ABSTRACT FROM AUTHOR]

Fitness tends to decline, whereas body fat increases, with age, which could impact firefighter occupational performance later in their careers. Health and wellness program participation could reduce these age-related changes. Archival data from 270 firefighters (258 men and 12 women) from a health and wellness program were analyzed. Data included body mass index; body fat percentage (BF%); waist circumference (WC); waist-to-hip ratio (WHR); sit and reach; grip strength; absolute and relative predicted 1 repetition maximum (1RM) leg press; crunches; push-ups; and estimated maximal aerobic capacity (Vo2max). Firefighters were grouped by age ≤29 (n = 29); 30-34 (n = 44); 35-39 (n = 38); 40-44 (n = 39); 45-49 (n = 48); 50-54 (n = 42); and 55+ (n = 30) years. A univariate analysis of covariance, with sex as a covariate and Bonferroni's post hoc adjustment, determined between-group differences. Effect sizes (d) were calculated. Key results included that the 55+ group had higher BF% and WC compared with the 3 youngest groups (p ≤ 0.002; d = 0.86-1.08). The 50-54 group had higher BF% than the 30-34 group (p = 0.010; d = 0.77). The 55+ group had a greater WHR, lower grip strength, and completed fewer crunches and push-ups than most younger groups (p ≤ 0.05; d = 0.60-1.32). The 50-54 and 55+ groups had a lower 1RM leg press and ...o2max compared with the younger groups (p ≤ 0.009; d = 0.77-1.79). The program appeared generally effective, with limited differences in groups below 49 years of age. Greater disparities in fat mass and fitness tended to occur in the older groups (50-54, 55+ groups). The data highlighted that older firefighters were participating in the optional program, which could lead to better health outcomes. [ABSTRACT FROM AUTHOR]

Aerobic fitness is linked with academy graduation, employment, and the long-term health of law enforcement officers and is often used as a training outcome. However, different tests can be used, and aerobic improvements may differ according to the test used. The aim of this study was to determine whether recruits improved to a greater extent in 1 aerobic test compared with the other. Retrospective data from 5 law enforcement recruit cohorts (males = 741; females = 353) who underwent 18 weeks of academy training were analyzed. Initial 20-m multistage fitness test (20MSFT) and 2.4-km run assessments were completed during weeks 4 and 5 of training, with final testing completed during weeks 16 and 17, respectively. A repeated-measures analysis of variance (p < 0.05) with a Bonferroni post hoc analysis determined changes in aerobic fitness in the 20MSFT and 2.4-km run between male and female recruits. A mean difference of 9.27 (95% confidence intervals [CI] 14.8-10.9; d = 0.63; p < 0.001) shuttle increase in 20MSFT performance and 20.1 (95% CI 16.0-24.2; d = 0.49; p < 0.001) second improvement in 2.4-km run time were demonstrated when averaged across sex, yielding a larger performance improvement forthe 20MSFT compared with the 2.4-km run. Conversely, there was a smaller magnitude of change in aerobic fitness between male recruits and female recruits for the 20MSFT(d = 0.47) compared with the 2.4-km run (d = 0.50). The findings indicate that current academy training results in improvements to aerobic fitness and to a greater magnitude in the 20MSFT compared with the 2.4-km run. These results may affect policy considerations for law enforcement agencies regarding aerobic test selection. [ABSTRACT FROM AUTHOR]

Purpose: Exercise-induced cell-free DNA (ei-cfDNA) has been studied in response to various types of exercise. Its correlation with exercise intensity and duration has been observed consistently. However, comprehensive measurements and exploration of the tissue of origin are lacking. The aim of this study is to establish precise connections between exercise variables and the distribution of tissue of origin, aiming to provide further evidence supporting its use as a biomarker for exercise. Methods: Twelve self-identified active adults (six men and six women) performed a crossover study starting with either endurance testing or resistance testing under different intensities and protocols. We obtained blood before and after each exercise session and measured the levels of cfDNA and determined its tissue of origin utilizing cell type-specific DNA methylation patterns in plasma. Results: We found that when duration and intensity are fixed, ei-cfDNA fold change correlates with energy expenditure (P = 0.001) in endurance testing and years trained (P = 0.001) in resistance testing. Most of the ei-cfDNA comes from increases in white blood cells (~95%) where neutrophils make up the majority (~74%) and the distribution is different between exercise modalities and protocols. Conclusions: This study highlights the potential of exercise-induced cfDNA as a biomarker for exercise, showing correlations with energy expenditure and a consistent pattern of tissue origin. Additional research is needed to investigate potential sex differences in the response of cfDNA to exercise, further exploring its clinical implications. [ABSTRACT FROM AUTHOR]

This study investigated the impact of fitness test performance on firefighter trainee ability to graduate an academy using ordinal logistic generalized linear models. Retrospective analysis was conducted on trainee data (N = 686) from one fire department who completed an occupational physical ability test (OPAT) that included the following: Illinois agility test (IAT); push-ups; pull-ups; leg tucks; maximal aerobic capacity (...); backward overhead 4.54-kg medicine ball throw (BOMBT); 10-repetition maximum deadlift; and 91.44-m farmer's carry. Data were recorded in raw and scaled scores based on internal scoring (tests scored from 0 to 100; maximum total OPAT score of 800). Trainees were split into graduated (n = 576) or released (n = 110) groups. Data were analyzed through ordinal logistic generalized linear models (p < 0.05). Raw and scaled scores were investigated separately, with odds ratios (OR) and confidence intervals (CI) produced. Regarding raw scores, there was a difference in the odds of graduating relative to the IAT (OR = 1.357; CI = 1.047-1.760; p = 0.021), BOMBT (OR = 0.744; CI = 0.628-0.882; p < 0.001), and V... (OR = 0.907; CI = 0.862-0.954; p < 0.001). For scaled scores, there was a difference in the odds of graduating relative to the points attained for the BOMBT (OR = 0.985; CI = 0.972-0.999; p = 0.032), deadlift (OR = 0.982; CI = 0.968-0.995; p = 0.008), and total OPAT (OR = 0.994; CI = 0.988-1.000; p = 0.047). Change-of-direction speed (IAT), total-body power (BOMBT), aerobic fitness (..., lower-body strength (deadlift), and overall fitness (total OPAT points) impacted the odds of trainee fire academy graduation. The IAT presented as the largest impacting variable where, for every unit increase in time (i.e., a slower IAT), there was 1.36 greater chance of a trainee being released from the academy. [ABSTRACT FROM AUTHOR]

Firefighter trainees need a level of fitness to be admitted to and complete a training academy. Fitness could indicate a trainee's likelihood of graduation, in addition to their reasons for release. This study determined fitness differences between firefighter trainees who graduated (GRAD) from academy or were released because of injury (RELI), performance test failures (RELP), or resignation (RELR), and whether fitness predicted graduation. Occupational physical ability test (OPAT) data for 686 trainees were analyzed, including: Illinois agility test; push-ups; pull-ups; leg tucks; maximal aerobic capacity (...O2max); backward overhead medicine ball throw; 10-repetition maximum deadlift; and farmer's carry. Raw and scaled (based on internal scoring) scores were recorded. Trainees were split into GRAD (n = 576), RELI (n 5 33), RELP (n = 66), and RELR (n = 11) groups. A 1-way ANOVA with Bonferroni post hoc calculated between-group differences. Stepwise linear regression determined whether fitness predicted group inclusion. Receiver operating curves and area under the curve (AUC) derived test accuracy for predicting academy release. The GRAD group was superior (p ≤ 0.04) to the RELI group in all tests except push-ups, pull-ups, and farmer's carry; RELP group in all tests except the farmer's carry; and RELR group in ...O2max, deadlift, and total OPAT score. Select fitness tests could predict inclusion in each group, although the explained variances were low (~1 -11%). Raw ...O2max (AUC = 0.71) and total OPAT score (AUC = 0.74) had acceptable prediction accuracy. Fitness influenced academy graduation and reasons for release. Scaled scores could predict group inclusion in this department; ...O2max and total OPAT score provided the most accurate predictors for release. [ABSTRACT FROM AUTHOR]

Basketball is a dynamic sport, requiring athletes to elicit a high-level of physical, tactical, technical, and psychological attributes and athletes must possess a robustly trained aerobic energy system. There is no research to assess how objectively measured training loads throughout a season influence aerobic capacity. The following study was a retrospective analysis of an NCAA Division I women's basketball team throughout a 5-month (23-week) competitive season. Data were sorted into season half totals and maximal oxygen consumption was recorded before, at the midway point and within 1-week postseason. Twelve athletes were monitored during each practice, pregame shoot around, scrimmage, and game for a total of 1,378 recorded sessions with a valid heart rate-based wearable microsensor (Polar Team Pro) during the season. There was a main effect of time for ...O2max throughout the season (p < 0.001). Post hoc analysis revealed there was a significant increase in ...O2max from preseason to postseason (p < 0.001). Interestingly, there were significant (p ≤ 0.001 for all) decreases from the first half to the second half of the season for training load, and time allocated to HRZone1-4, but no difference in time for the most intense zone, HRzone5. Conclusion: Oxygen consumption significantly increased 7.5% from preseason to postseason despite a reduction in overall work. The only training intensity that was not different from the first half to second half of the season was time in the highest heart rate intensity zone ≥85% of HRmax. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Return to performance (RTP) protocols vary greatly between sports due to energy system involvement, physical and biomechanical skills, injury type and severity, and varied recommendations from members of the interprofessional care team. Return decisions are guided by clinical reasoning, expert opinion, experience, and sport-specific frameworks. Lower extremity injuries that prevent athletes from continuous aerobic training lead to decreased aerobic capacity upon return, which is linked to increased risk of injury or reinjury. This narrative review compares documented rehabilitation programs and RTP protocols and criteria specific to aerobic capacity for athletes who sustain lower extremity injuries in highly aerobic sports. Databases were searched from 2010 to 2022, yielding 9 primary articles and 11 review articles. No RTP protocol specific to aerobic capacity was identified. Considering the lack of evidence regarding aerobic capacity testing and prescription in RTP protocols, research is necessary to determine the significance of aerobic capacity recommended for RTP. Strength and conditioning coaches should be aware of the decreased aerobic capacity at the time of return, thus the need for additional testing, and implement individualized aerobic conditioning programs to optimize return.. [ABSTRACT FROM AUTHOR]

Purpose: Long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) may enhance recovery from exercise-induced muscle damage (EIMD). However, it is unclear if the effects are due to EPA, DHA, or both. The purpose of this investigation was to examine the effect of EPA + DHA, EPA, and DHA compared with placebo (PL) on muscular recovery. Methods: Thirty males were randomized to 4 g·d−1 EPA + DHA (n = 8), EPA (n = 8), DHA (n = 7), or PL (n = 7). After 7-wk supplementation, a downhill running (20 min, 70% V̇O2max, −16% gradient) plus jumping lunges (5 × 20 reps, 2-min rest intervals) muscle damage protocol was performed. Indices of muscle damage, soreness, muscle function, and inflammation were measured at baseline and throughout recovery. The omega-3 index (O3i; %EPA + %DHA in erythrocytes) was used to track tissue EPA and DHA status. Results: After supplementation, the O3i was significantly higher than PL in all experimental groups (P < 0.001). Leg press performance was lower in the PL group at 24 h compared with EPA (P = 0.019) and at 72 h for EPA (P = 0.004) and DHA (P = 0.046). Compared with PL, muscle soreness was lower in the DHA (P = 0.015) and EPA (P = 0.027) groups at 48 h. Albeit nonsignificant, EPA + DHA tended to attenuate muscle soreness (d = 1.37) and leg strength decrements (d = 0.75) compared with PL. Jump performance and power metrics improved more rapidly in the EPA and DHA groups (time effects: P < 0.001). Measures of inflammation, range of motion, and muscle swelling were similar between groups (P > 0.05). Conclusions: Compared with PL, 4 g·d−1 of EPA or DHA for 52 d improves certain aspects of recovery from EIMD. EPA + DHA did not clearly enhance recovery. Equivalent dosing of EPA + DHA may blunt the performance effects observed in EPA or DHA alone. [ABSTRACT FROM AUTHOR]

Juvenile fibromyalgia (JFM) is a chronic condition characterized by symptoms of pain and fatigue and is associated with sedentary behavior and functional disability. Adults with fibromyalgia exhibit deficits in physical fitness as evidenced by lower aerobic capacity and physical endurance, but it is unknown whether these impairments are apparent in adolescents with JFM. Furthermore, the extent to which functional disability and pain interference relate to measures of physical fitness has not been investigated in a pediatric pain population. During a baseline assessment for a clinical trial, 321 adolescents with juvenile fibromyalgia (Mage = 15.14, 85.2% female) completed measures of pain intensity, fatigue, JFM symptom severity, functional disability, and pain interference. They also completed 2 validated fitness tasks: (1) the Harvard step test, which assesses aerobic fitness, and (2) the 6-minute walk test, a simple submaximal test of endurance. We examined associations among self-report measures and fitness assessments using bivariate correlations. We then employed hierarchical regression analyses to determine the unique contributions of physical fitness assessments to self-reported functional disability and pain interference. Results indicated that youth with JFM exhibited deficits in aerobic capacity and physical endurance. However, physical fitness explained negligible variance in functional disability and pain interference beyond that accounted for by pain, fatigue, and JFM symptom severity. Scores on available functional disability measures may reflect perceived difficulties in coping with symptoms during physical tasks rather than actual physical capability. Rigorous and sensitive assessments of physical fitness and endurance are needed to determine whether rehabilitation interventions for pediatric pain improve physical functioning. [ABSTRACT FROM AUTHOR]

OBJECTIVES: An association between physical inactivity and worse outcome during infectious disease has been reported. The effect of moderate exercise preconditioning on the immune response during an acute pneumonia in a murine model was evaluated. SETTING: Laboratory experiments. SUBJECTS: C57BL6/j male mice. INTERVENTIONS: Six-week-old C57BL/6J mice were divided in two groups: an exercise group and a control group. In the exercise group, a moderate, progressive, and standardized physical exercise was applied for 8 weeks. It consisted in a daily treadmill training lasting 60 minutes and with an intensity of 65% of the maximal theoretical oxygen uptake. Usual housing recommendation were applied in the control group during the same period. After 8 weeks, pneumonia was induced in both groups by intratracheal instillation of a fixed concentration of a Klebsiella pneumoniae (5 x 103 colony-forming unit) solution. MEASUREMENTS AND MAIN RESULTS: Mice preconditioned by physical exercise had a less sever onset of pneumonia as shown by a significant decrease of the Mouse Clinical Assessment Severity Score and had a significantly lower mortality compared with the control group (27% vs. 83%; p = 0.019). In the exercise group, we observed a significantly earlier but transient recruitment of inflammatory immune cells with a significant increase of neutrophils, CD4+ cells and interstitial macrophages counts compared with control group. Lung tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-10 were significantly decreased at 48 hours after pneumonia induction in the exercise group compared with the control group. CONCLUSIONS: In our model, preconditioning by moderate physical exercise improves outcome by reducing the severity of acute pneumonia with an increased but transient activation of the innate immune response. [ABSTRACT FROM AUTHOR]

Ruiz-Alias, SA, Nncupil-Andrade, AA, Pe' rez-Castilla, A, and Garc'ıa-Pinillos, F. Can we predict long-duration running power output? Validity of the critical power, power law, and logarithmic models. J Strength Cond Res 38(2): 306-310, 2024--Predicting long-distance running performance has always been a challenge for athletes and practitioners. To ease this task, different empirical models have been proposed to model the drop of the running work rate with the increase of time. Therefore, this study aims to determine the validity of different models (i.e., CP, power law, and Peronnet) to predict long-duration running power output (i.e., 30 and 60 minutes). In a 4-week training period, 15 highly trained athletes performed 7-time trials (i.e., 3, 4, 5, 10, 20, 30, and 60 minutes) in a randomized order. Then, their power-duration curves (PDCs) were defined through the work-time critical power model (CPwork), power-1/time (CP1/time), 2-parameter hyperbolic (CP2hyp), 3-parameter hyperbolic (CP3hyp), the undisclosed Stryd (CPstryd), and Golden Cheetah (CPcheetah) proprietary models, and the power law and Peronnet models using the 3 to 20 minutes time trials. These ones were extrapolated to the 30- and 60-minute power output and compared with the actual performance. The CP2hyp, CP3hyp, CPstryd, and CPcheetah provided valid 30- and 60-minute power output estimations (#2.6%). The CPwork and CP1/time presented a large predicting error for 30 minutes ($4.4%), which increased for 60 minutes ($8.1%). The power law and Peronnet models progressively increased their predicting error at the longest duration (30 minutes: #21.6%; 60 minutes: #2 6.6%), which was conditioned by the endurance capability of the athletes. Therefore, athletes and practitioners are encouraged to applicate the aforementioned valid models to their PDC to estimate the 30-minute and 60-minute power output. [ABSTRACT FROM AUTHOR]

Gonzalo-Skok, O, and Bishop, C. Influence of maturation and determinants of repeated-sprint ability in youth basketball players. J Strength Cond Res 38(2): 325-333, 2024--The main aims of the current study were (a) to determine the main predictors of general and specific repeated-sprint ability (RSA) tests, (b) to analyze the relationships between RSA tests and independent measures of physical performance, (c) to examine whether between-age differences exist, and (d) to assess whether maturation affects those mentioned above in young basketball players. Thirty-five young (U-14 to U-16), highly trained basketball players performed a linear sprint test (5, 10, and 25 m), an incremental running test, and 2 repeated-sprint tests (general [RSG]: 6325 m; specific [RSS]: 635 + 5 m with a 45° change of direction and 20 seconds of passive recovery in both tests). Anthropometric variables were measured and used to calculate age at peak height velocity (APHV), which was used to determine maturation. The main determinants of RSA tests were aerobic performance and linear sprinting for RSS (R250.84) and adding the percentage of body fat for RSG (R250.94). Almost perfect relationships (r 5 0.93-0.99) were found between all RSA variables (i.e., the best [RSGb and RSSb] and mean time [RSGm and RSSm]). As age increased, performance in RSA was evident, as shown by improved best and mean scores. When APHV was controlled for, no significant differences were apparent in the comparison from U-14 and U-16 in 25 m, RSGb, and RSGm. By contrast, significant differences (p < 0.05) were still evident with APHV controlled between U-14 and U-16 in 5m, 10m, RSSb, and RSSm. In conclusion, maturation positively affects linear sprinting and linear RSA performance, whereas specific (multidirectional) RSA seems to be related to other factors. [ABSTRACT FROM AUTHOR]

The article discusses the relationship between inducible ischemia severity, coronary artery disease (CAD) extent, and exercise capacity in patients with chronic coronary disease. The study, called ISCHEMIA, analyzed data from 858 participants who underwent exercise treadmill testing. The results showed that neither ischemia severity nor CAD extent were significant predictors of aerobic exercise capacity beyond demographic and clinical characteristics. These findings are surprising given the expected relationship between exercise limitation and CAD, but recent studies have also questioned this relationship. The study has some limitations, such as the skewed cohort and the lack of follow-up exercise testing. Overall, the article provides valuable insights into the association between ischemia severity, CAD extent, and exercise capacity in patients with chronic coronary disease. [Extracted from the article]

This article discusses the potential benefits of ketones in improving cardiac function in patients with chronic heart failure (HF). The study examined the effects of oral ketone supplementation on cardiac, vascular, and hemodynamic function in patients with stable HF. The results showed that oral ketone supplementation was safe and led to improvements in resting cardiac output, ejection fraction, and vascular resistance. However, the study also highlighted the need for further research to determine the specific mechanisms by which ketones improve cardiac function and to identify which patient populations would benefit the most from ketone therapy. [Extracted from the article]

Iron Absorption in Highly Trained Male Runners: Does it Matter When and Where You Eat Your Iron?. Med. Sci. Sports Exerc., Vol. 56, No. 1, pp. 118-127, 2024. Purpose: We examined iron absorption and its regulation during two common scenarios experienced by endurance athletes. Our aims were to: (i) compare the effects of preexercise versus postexercise iron intake on iron absorption; and (ii) compare the impact of training at altitude (1800 m) on iron absorption preexercise. Methods: Male runners (n = 18) completed three exercise trials over a 5-wk period, each preceded by 24 h of standardized low-iron diets. First, athletes completed two 60-min treadmill running trials at 65% VO˙ 2max at near sea-level (580 m). In a randomized order, preexercise and postexercise test meals labeled with 4 mg of 57Fe or 58Fe were consumed 30 min before or 30 min after exercise. Then, the same exercise trial was performed after living and training at altitude (~1800 m) for 7 d, with the labeled test meal consumed 30 min preexercise. We collected venous blood samples preexercise and postexercise for markers of iron status and regulation, and 14 d later to measure erythrocyte isotope incorporation. Results: No differences in fractional iron absorption were evident when test meals were consumed preexercise (7.3% [4.4, 12.1]) or postexercise (6.2% [3.1, 12.5]) (n = 18; P = 0.058). Iron absorption preexercise was greater at altitude (18.4% [10.6, 32.0]) than at near sea-level (n = 17; P < 0.001) and hepcidin concentrations at altitude were lower at rest and 3 h postexercise compared with near sea level (P < 0.001). Conclusions: In an acute setting, preexercise and postexercise iron absorption is comparable if consumed within 30 min of exercise. Preexercise iron absorption increases 2.6-fold at altitude compared with near sea-level, likely due to the homeostatic response to provide iron for enhanced erythropoiesis and maintain iron stores. [ABSTRACT FROM AUTHOR]

HAPI Fit: An Exercise Intervention to Improve Peak Aerobic Capacity in Young Adults Born Very Preterm. Med. Sci. Sports Exerc., Vol. 56, No. 1, pp. 44-52, 2024. Introduction: Individuals born preterm have reduced aerobic capacity, which could be related to impaired organ development. Their capacity to improve aerobic capacity with exercise training could therefore be limited, but this remains unknown. We aimed to test an exercise intervention to improve cardiorespiratory fitness in adults born preterm. Methods: Twenty-one very preterm and 37 full-term individuals aged 18–33 yr took part in a 14-wk supervised exercise intervention of cardiovascular, resistance, and flexibility training (two group and one individual sessions per week). Adherence and compliance to intervention were recorded. Primary outcome was change in peak oxygen consumption (peak VO˙ 2) measured before and after the intervention. Within- and between-group differences were estimated using nonparametric tests. Results: Of 219 eligible individuals, 58 were enrolled and 14 participants dropped out over the course of the intervention. Among the 44 who completed the intervention, mean adherence was 82% and 66% for group and individual sessions, respectively. Compliance with training requirement varied between 71% and 100%. There was no difference in adherence between the preterm and full-term groups. Because only one preterm male met the adherence criteria, subsequent analyses were done exclusively on females. Both the term and preterm groups achieved higher peak VO˙ 2 after the intervention [term = +4.2 (SD 4.3) mL·min-1 ·kg-1, P < 0.01; preterm = +4.7 (2.9) mL·min-1 ·kg-1, P < 0.01]. There was no between-group difference in the response to the intervention (P = 0.729). Conclusions: Recruitment and adherence to an exercise intervention are challenging. Results could indicate improvements in cardiorespiratory fitness in young women born preterm after current exercise program. Adaptation of this intervention is needed for wider uptake. [ABSTRACT FROM AUTHOR]

Tactical periodization (TP) emerged approximately 30 years ago and has recently gained considerable attention in rugby union (RU). It aims to develop specific physical fitness components with 3 acquisition days (strength, endurance, and speed). However, no study has investigated the effects of TP on workload, physical fitness, and well-being across an RU preseason. This study aimed to determine how RU players' workload response to TP focusing on positional differences, observe the influence of a TP preseason training program on aerobic fitness and neuromuscular performance between positions, and analyze the variation of well-being reported by forwards and backs from the 3 acquisition days. Thirty-two male players completed a 6-week TP protocol. External and internal workload variables were recorded through global positioning systems and session rating of perceived exertion (s-RPE) separately. Fitness assessments included Bronco and countermovement jump (CMJ) tests. The sum of well-being indices was measured using the Hooper index. Kruskal-Wallis H tests revealed that the highest values of PlayerLoad slow, PlayerLoad slow percentage, and s-RPE were found on endurance day and the lowest on speed day. Mann-Whitney U tests showed that 15 external workload parameters were higher in backs than forwards for each acquisition day. Small improvements were observed on the Bronco test. No differences were observed in CMJ performance during the preseason period and well-being values between acquisition days. This study provides unique insights into external and internal workload variables during each acquisition day. Furthermore, it highlights TP as an efficient theoretical concept to use in an RU context. [ABSTRACT FROM AUTHOR]

Via the identification of the ramp-specific gas exchange threshold (GET) and respiratory compensation point (RCP), the recently validated step--ramp--step (SRS) protocol enables the prediction of the power outputs at the lactate threshold and maximal metabolic steady state. Purpose: We aimed to test the extended capabilities of the SRS protocol by validating its capacity to predict the power outputs for targeted metabolic rates (VO2) and time-to-task failure (Tlim) within the heavy- and severe-intensity domain, respectively. Methods: Fourteen young individuals completed (i) an SRS protocol from which the power outputs at GET and RCP (RCPCORR), and the work accruable above RCPCORR, defined as WRAMP, were derived; (ii) one heavy-intensity bout at a power output predicted to elicit a targeted VO2 equidistant from GET and RCP; and (iii) four severe-intensity trials at power outputs predicted to elicit targeted Tlim at minutes 2.5, 5, 10, and 13. These severe-intensity trials were also used to compute the constant-load--derived critical power and W´ (WCONSTANT). Results: Targeted (2.41 ± 0.52 L·min-1) and measured (2.43 ± 0.52 L·min-1) VO2 at the identified heavy-intensity power output (162 ± 43 W) were not different (P = 0.71) and substantially concordant (CCC = 0.95). Likewise, targeted and measured Tlim for the four identified severe-intensity power outputs were not different (P > 0.05), and the aggregated coefficient of variation was 10.7% ± 8.9%. The derived power outputs at RCPCORR (192 ± 53W) and critical power (193 ± 53 W) were not different (P = 0.65) and highly concordant (CCC = 0.99). There were also no differences between WRAMP and WCONSTANT (P = 0.51). Conclusions: The SRS protocol can accurately predict power outputs to elicit discrete metabolic rates and exercise durations, thus providing, with time efficiency, a high precision for the control of the metabolic stimulus during exercise. [ABSTRACT FROM AUTHOR]

Objective: Exercise training is a cornerstone of the treatment of chronic obstructive pulmonary disease, whereas the related interindividual heterogeneity in skeletal muscle dysfunction and adaptations are not yet fully understood. We set out to investigate the effects of exercise training and supplemental oxygen on functional and structural peripheral muscle adaptation. Methods: In this prospective, randomized, controlled, double-blind study, 28 patients with nonhypoxemic chronic obstructive pulmonary disease (forced expiratory volume in 1 second, 45.92% ± 9.06%) performed 6 wk of combined endurance and strength training, three times a week while breathing either supplemental oxygen or medical air. The impact on exercise capacity, muscle strength, and quadriceps femoris muscle cross-sectional area (CSA) was assessed by maximal cardiopulmonary exercise testing, 10-repetition maximum strength test of knee extension, and magnetic resonance imaging, respectively. Results: After exercise training, patients demonstrated a significant increase in functional capacity, aerobic capacity, exercise tolerance, quadriceps muscle strength, and bilateral CSA. Supplemental oxygen affected significantly the training impact on peak work rate when compared with medical air (+0.20 ± 0.03 vs +0.12 ± 0.03 W·kg--1, P = 0.047); a significant increase in CSA (+3.9 ± 1.3 cm2, P = 0.013) was only observed in the training group using oxygen. Supplemental oxygen and exercise-induced peripheral desaturation were identified as significant opposing determinants of muscle gain during this exercise training intervention, which led to different adaptations of CSA between the respective subgroups. Conclusions: The heterogenous functional and structural muscle adaptations seem determined by supplemental oxygen and exercise-induced hypoxia. Indeed, supplemental oxygen may facilitate muscular training adaptations, particularly in limb muscle dysfunction, thereby contributing to the enhanced training responses on maximal aerobic and functional capacity. [ABSTRACT FROM AUTHOR]

Aim: This study investigated the development of power profiles and performance-related measures from the junior level (<19 yr) via U23 (19-23 yr) to senior level (>23 yr) in 19 female and 100 male Norwegian national team cyclists. Methods: A total of 285 tests were performed in a 3-d laboratory-standardized testing regime. The tests included power profiles with shorter duration (6-60 s) and longer durations (12-30 min) together with performance-related measures: critical power (CP), work capacity above CP (W'), power output at 4 and 2 mmol·L-1 [BLa-] (L4 and L2), maximal aerobic power (Wmax), and maximal oxygen uptake (VO2max), gross efficiency (GE), and pedaling efficiency. Results: Females and males evolve similarly when maturing from junior via U23 to senior categories (all P > 0.07), except for VO2max, which increased in females (but not males) from junior to senior level (534 ± 436 mL·min-1, P = 0.013). In general, only performances of longer durations improved with age (12 and 30min, P = 0.028 and P = 0.042, respectively). Performance-relatedmeasures likeWmax, VO2max, CP, L4, L2, and pedaling efficiency in the fresh state improved with age (all P = 0.025). Importantly, performance in the semifatigued state during a 5-minmaximal testwas also improvedwith age (P = 0.045) despite a higher external energy expenditure before the test (P=0.026). Conclusions: Junior cyclists showhighly developed sprint abilities, and the primary improvements of absolute power outputs and performance-relatedmeasures are seen for durations >60 s whenmaturing toU23 and senior categories. However, the durability, i.e., the capacity tomaintain performance in a semifatigued state, is improved with age. [ABSTRACT FROM AUTHOR]

Hingrand, C, Olivier, N, Combes, A, Bensaid, S, and Daussin, FN. Power is more relevant than ascensional speed to determine metabolic demand at different gradient slopes during running. J Strength Cond Res 37(11): 2298-2301, 2023--Trail running is characterized by successive uphill and downhill running sessions. To prescribe training intensity, an assessment of maximal running capacity is required. This study compared 2 uphill incremental tests using the same ascensional speed increment to identify the influence of the slope gradient on performance. Ten subjects (8 men and 2 women) performed 3 incremental exercises on various slope (1%: IT01, 10%: IT10, and 25%: IT25), and the ascensional speed increment was similar between IT10 and IT25 (100 m·h21 every minute). Gas exchanges, heart rate, and power were monitored continuously during the tests. Similar V̇O2max levels were observed in the 3 conditions: 68.766.2 for IT01, 70.167.3 for IT10, and 67.667.0 for IT25. A greater maximal ascensional speed was reached in the IT25 (1760 6 190 vs. 1,330 6 106 for IT25 and IT10, respectively, p, 0.01). A significant relationship was observed between relative V̇O2 levels and relative power without any effect of slope. Power should be the parameter used for prescribing training intensity compared with ascensional speed in trail. [ABSTRACT FROM AUTHOR]

Carder, MJ, Scudamore, EM, Savanna, KN, Pribyslavska, V, Bowling, LR, and O'Neal, EK. Retrospective and contemporary predictors of National Collegiate Athletic Association Division I cross-country performance are sex specific. J Strength Cond Res 37(11): 2267-2272, 2023--The purpose of this study was to identify National Collegiate Athletic Association (NCAA) Division I cross-country (XC) performance potential using laboratory-based and field-based parameters and retrospective high school (HS) personal best (PB) data at various distances of current collegiate XC runners. Fifteen female and 17 male NCAA XC runners provided their PB for 5-km (women) and 8-km (men) distances from the previous season. Bivariate correlation and stepwise and hierarchical regression modeling were used to predict XC performance. Single squat jump height and multijump reactive strength index displayed r, 0.27 for both sexes, suggesting lower-body power is a poor predictor of XC performance or masked by other factors of greater importance. Triceps skinfold thickness approached significance (r50.43; p50.09) for men but was unrelated to women's performance (r 5 20.05; p 5 0.86). HS XC PB neared significance (r 5 0.55, p 5 0.054), but no other single or combination of variables reached significance for female runners. Aerobic capacity displayed a moderate to strong relationship (r5 0.65) for male runners. High school 3,200-m PB for men produced a robust prediction capacity (r50.85; p50.005, SEE560.65 minutes), and predicted 8-km PB within 30 seconds for approximately two-thirds of runners. These outcomes suggest when recruiting HS or transfer athletes, male and female XC runners should not be recruited on the same factors. Women's XC PB is more difficult to predict, but skinfold thickness was statistically the least valuable predictor of all factors. [ABSTRACT FROM AUTHOR]

Fields, JB, Kuhlman, NM, Jagim, AR, Dulak-Sigler, C, and Jones, MT. Analysis of accumulated workloads and performance testing across a collegiate women's lacrosse season. J Strength Cond Res 37(11): 2213-2221, 2023--Monitoring accumulated workloads, acute:chronic workload ratios (ACWR), and training monotony (TM) are practical methods for monitoring athlete physical stress. Performance testing provides useful information about the changing nature of physical abilities. Therefore, the purpose was to examine differences in accumulated workloads based on session type, explore seasonal trends in ACWR and TM, and assess changes in performance assessments in collegiate women's lacrosse athletes. Athletes, who were identified as starters (n 5 12), wore positional monitoring technology during training sessions (n 5 61) and games (n 5 17) and completed preseason and postseason assessments of speed, agility, power (jump tests), strength, aerobic capacity, and body composition. Separate 1-way analyses of variance were used to determine differences in accumulated workloads for session type and differences in performance assessments from preseason to postseason (p,0.05). When compared with games, practice sessions elicited greater (p,0.001) accumulated total distance, player load, repeated high-intensity efforts, accelerations, change of direction, explosive efforts, highspeed efforts (p 5 0.002), and high-speed distance (p 5 0.002). Throughout the season, ACWR and TM ranged from 0.16 to 1.40 AU and 0.68-1.69 AU, respectively. The 40-yd sprint (p, 0.001) and pro-agility (p, 0.001) improved from preseason to postseason, whereas no changes in aerobic capacity, lower-body power, or strength were observed (p. 0.05). The monitoring of accumulated loads, ACWR and TM, and performance tests revealed novel information about the seasonal demands of collegiate women's lacrosse. Women lacrosse players are able to improve speed and agility throughout the season, while maintaining strength, power, and endurance, with minimal reductions in fat-free mass. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to investigate the effectiveness of novel repeated-sprint training in hypoxia (RSH) protocol, likelymaximizing hypoxic stimulus (higher than commonly used) while preserving training quality (interset rest in normoxia). Methods: Twenty-three world-class female rugby sevens players performed four repeated-sprint training sessions (4 sets of 5 × 5-s cycle sprints--25-s intersprint recovery and 3-min interset rest) under normobaric hypoxia (RSH, exercise and interset rest at FiO2 of 10.6% and 20.9%, respectively; n = 12) or normoxia (repeated-sprint training in normoxia; exercise and interset rest at FiO2 of 20.9%; n = 11) during a 9-d training camp before international competition. Repeated-sprint ability (8 × 5-s treadmill sprints--25-s recovery), on-field aerobic capacity, and brachial endothelial function were assessed pre- and postintervention. Results: Arterial oxygen saturation (pooled data: 87.0% ± 3.1% vs 96.7% ± 2.9%, P < 0.001) and peak and mean power outputs (sets 1 to 4 average decrease: -21.7%± 7.2%vs -12.0%± 3.8% and -24.9%± 8.1%vs -14.9%± 3.5%; both P < 0.001) were lower in RSH versus repeated-sprint training in normoxia. The cumulated repeated-sprint distance covered significantly increased frompre- to postintervention (+1.9%± 3.0%, P = 0.019), irrespective of the condition (P = 0.149). On-field aerobic capacity did not change (all P > 0.45). There was no significant interaction (all P > 0.240) or conditionmain effect (all P > 0.074) for any brachial artery endothelial function variable. Only peak diameter increased (P = 0.026), whereas baseline and peak shear stress decreased (P = 0.014 and 0.019, respectively), from pre- to postintervention. Conclusions: In world-class female rugby sevens players, only four additional repeated-sprint sessions before competition improve repeated-sprint ability and brachial endothelial function. However, adding severe hypoxic stress during sets of repeated sprints only did not provide supplementary benefits. [ABSTRACT FROM AUTHOR]

Purpose: ACSMguidelines state that aerobic exercise intensity should be 30%/40% to 89% VO2reserve (VO2R) or heart rate reserve (HRR). Determining the proper intensity within this range is the "art" of exercise prescription, often relying on rating of perceived exertion (RPE) as the adjunctive intensity modulator. Current guidelines do not consider the use of ventilatory threshold (VT) due to the need for specialized equipment and methodological issues. The purpose of this investigation was to evaluate VT related to VO2peak, VO2R, HRR, and RPE across the full spectrum of very low to very high VO2peak values. Methods: Eight hundred and sixty-three records of exercise tests were retrospectively examined. Data were stratified for VO2peak, activity level, age, test modality, and sex. Results: When stratified for VO2peak, VO2 at VT (VO2vt) had a lower mean value of ~14mL·kg-1·min-1 in the lowest fit, rose gradually untilmedian VO2peak, and rose steeply thereafter. When graphed relative to VO2peak, VO2vt as a percentage of VO2R (VT% V̇O2R) resembled a U-shaped curve, with a nadir ~43% VO2R at V̇O2peak ~40mL·kg-1·min-1. Average VT%V O2R increased to ~75%in groups with the lowest or highest VO2peak. There was a large variance in the value of VT at all VO2peak levels. Mean RPE at VT was 12.5 ± 0.93, regardless of VO2peak. Conclusions: Given the relationship of VT as the transition from moderate- to higher-intensity exercise, these data may help the understanding of aerobic exercise prescription in persons across the spectrum of VO2peak values. [ABSTRACT FROM AUTHOR]

The time-of-day effect of exercise on human function remains largely equivocal. Hence, this study aimed to further analyze the existing evidence concerning diurnal variations in cardiorespiratory responses and endurance performance using a meta-analytic approach. Literature search was conducted through databases, including PubMed, CINAHL, and Google Scholar. Article selection was made based on inclusion criteria concerning subjects' characteristics, exercise protocols, times of testing, and targeted dependent variables. Results on oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio, and endurance performance in the morning (AM) and late afternoon or evening (PM) were extracted from the chosen studies. Metaanalysis was conducted with the random-effects model. Thirty-one original research studies that met the inclusion criteria were selected. Meta-analysis revealed higher resting VO2 (Hedges' g = -0.574; p = 0.040) and resting HR (Hedges' g= -1.058; p = 0.002) in PM than in AM. During exercise, although VO2 remained indifferent between AM and PM, HR was higher in PM at submaximal (Hedges' g = -0.199; p = 0.046) and maximal (Hedges' g = -0.298; p = 0.001) levels. Endurance performance as measured by time-to-exhaustion or the total work accomplished was higher in PM than in AM (Hedges' g = -0.654; p = 0.001). Diurnal variations in VO2 appear less detectable during aerobic exercise. The finding that exercising HR and endurance performance were greater inPMthan in AMemphasizes the need to consider the effect of circadian rhythm when evaluating athletic performance or using HR as a criterion to assess fitness or monitor training. [ABSTRACT FROM AUTHOR]

1 Rep Max (1RM) Living occurs when the demands of life are near or exceeding one's capacity. This situation can be troublesome and relatively urgent for many. Telerehabilitation offers some barriers but also opportunities to helping people in this common situation. This article discusses the importance of 1RM Living, how to identify, and how we can destroy 1RM Living to change our patients' lives for the better. [ABSTRACT FROM AUTHOR]

This study assessed player (i.e., lower-body strength and power and aerobic fitness) and environmental (e.g., venue) factors and their effects on the physical (e.g., distance) and technical (e.g., kicks) demands of Australian football (AF). Relative distance, high-speed running (HSR), and acceleration efforts for 19 matches by 33 players in a West AF League team were analyzed from global positioning system data split into periods of successful offense and defense and maximum ball in play (BiP) periods, as well as technical actions. Lower-body strength and power, and aerobic fitness were evaluated using a one-repetition trap-bar deadlift, countermovement jump, 2-km time trial, and Yo-Yo intermittent fitness test, respectively. In matches played at home, distance (p < 0.001, ES = 0.39) and HSR (p < 0.001, ES = 0.34) were significantly reduced during successful defense. In addition, tackle rate was significantly increased (p = 0.003, ES = 0.16) during successful defense when playing at home. Trap-bar deadlift relative to mass significantly increased relative distance (p = 0.004, ES = 0.51) and HSR (p = 0.029, ES = 0.40) in successful offense. In successful defense, superiortime trial performance significantly increased relative distance (p < 0.001, ES = 0.58), HSR (p < 0.001, ES = 0.59), and acceleration efforts (p = 0.017, ES = 0.44), while relative distance (p < 0.001, ES = 0.62) and HSR (p = 0.004, ES = 0.52) were also increased during maximum BiP periods. The results demonstrate that player factors have the largest effect on the physical and technical performance of AF players. [ABSTRACT FROM AUTHOR]

Sprint interval training (SIT) refers to a set of brief intermittent exercises that are performed at maximal intensity. This study compared the effects of 2 SIT protocols (e.g., 10-5-SIT and 20-10-SIT) vs. moderate-intensity continuous training (MICT) on cardiovascular adaptations, using stationary air bikes. Thirty-two recreationally active individuals were randomly assigned to the 3 performance groups, such as 10-5-SIT (n = 11), 20-10-SIT(n 5 10), and MICT (n = 11), to train 3 days per week for 4 weeks. Moderate-intensity continuous training included 30 minutes of cycling at 75% of maximal heart rate reserve, whereas the SIT protocols consisted of 3 sets of 8 intervals at all-out intensity. The 10-5-SITand 20-10-SIT were performed with 10-second work:5-second rest and 20-second work:10-second rest, with 2.5- and 5-minute recovery periods between sets, respectively. A ramp protocol was used before and after the intervention via cycle ergometer to assess aerobic performance. Time to exhaustion (TTE), absolute ...O2max (A-...O2max), relative ...O2max (R-...O2max), and metabolic equivalents (METs) were measured and analyzed with 2-way mixed factorial analyses of variance (ANOVAs). In addition, total work (TW) during 12 sessions were recorded and analyzed with 1-way ANOVA. Significant (p < 0.05) differences were found for TW (10-5-SIT: 907.3 ± 332.0, 20-10-SIT: 1230.0 ± 188.1, and MICT: 2263.0 ± 896.9 calories) between groups. A significant main effect of time was observed for 10-5-SIT, 20-10-SIT, and MICT (p < 0.05) in TTE (increased by 7.3, 8.7, and 8.2%), A-...O2max (increased by 13.0, 11.8, and 13.6%), R-...O2max (increased by 12.6, 12.1, and 14.8%), and METs (increased by 12.7, 12.3, and 14.9%), respectively. Despite less volume and duration, both SIT protocols induced cardiorespiratory adaptations similar to MICT. These findings suggest that performing SIT on a stationary air bike is valuable because of time-efficiency and cardiorespiratory adaptations. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine longitudinal changes in fitness and body composition throughout athletes' 4-year collegiate soccer careers. Performance testing occurred before preseason during freshman, sophomore, junior, and senior year in 17 female Division I soccer players. Body composition was assessed through air-displacement plethysmography to determine percent body fat (%BF), fat-free mass (FFM), and body mass (BM). Maximal countermovement vertical jump height was assessed through contact mat using arm swing (CMJAS) and hands-on-hips (CMJHOH) methods to calculate power (CMJwatts/HOHwatts). Aerobic capacity (V̇o2max) and ventilatory threshold (VT) were assessed by indirect calorimetry during a maximal graded exercise test on a treadmill. Linear mixed models were used to assess changes across academic years (p < 0.05). No changes occurred in %BF, BM, V̇o2max, VT, CMJAS, or CMJwatts. A time main effect was seen for FFM (p = 0.01) with increases from freshman to senior (p = 0.02). Time main effects were observed for CMJHOH (p < 0.001) and CMJHOHwatts (p < 0.001) with increases from freshman to junior (CMJHOH,p = 0.001; CMJHOHwatts, p = 0.02) and senior (CMJHOH, p < 0.001; CMJHOHwatts, p = 0.003) as well as sophomore to senior (CMJHOH, p < 0.001; CMJHOHwatts, p = 0.02). Countermovement vertical jump with hands on hips also increased from sophomore to junior (p = 0.005). The lower FFM and power capabilities as freshmen compared with upperclassman indicate a potential limited readiness. Coaches and training staff should account for these developmental differences when entering the preseason. Adequate conditioning programs before starting a collegiate program may help build a fitness foundation and prepare freshmen athletes to compete at the same level as their upperclassmen counterparts. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to examine the time course of health, fitness, and occupational performance changes in firefighter recruits across a fire academy. Methods: Nineteen recruits (24.9 ± 4.3 yr; 26.7 ± 3.1 kg·m−2) had their body composition, balance, vertical jump (VJ) performance, cardiorespiratory fitness (CRF), upper and lower body strength, hamstrings-to-quadriceps (H/Q) ratio, lower back endurance, and weighted stair climb (SC) performance assessed at the beginning (week 1 [W1]), midpoint (week 15 [W15]), and end (week 30 [W30]) of a fire academy. Results: The fire academy improved body composition, balance, CRF, leg extension strength, and SC performance from W1 to W15 (P ≤ 0.042) which then plateaued at W30 (P ≥ 0.314). Leg flexion strength and the H/Q ratio decreased from W1 to W15 (P ≤ 0.035) and plateaued at W30 (P ≥ 0.947). Upper body strength was similar at W1 and W15 (P ≥ 0.999), but decreased at W30 (P ≤ 0.033). However, no significant changes occurred across the academy for VJ performance or lower back endurance (P ≥ 0.090). Conclusions: These findings highlight the positive effect of the academy on body composition, CRF, balance, SC performance, and leg extension strength. However, the decreases in upper body and leg flexion strength, the H/Q ratio, and lack of changes in VJ performance and low back endurance may highlight key areas of need to maximize injury prevention and performance enhancement efforts in the academy. Further, the varied time course of changes may help fire departments identify opportunities to modify exercise programming across their academies. [ABSTRACT FROM AUTHOR]

The verification phase is becoming the norm for confirming V̇O2max during a graded exercise test (GXT), but the use of such testing in untrained participants in the heat remains unknown. Purpose: This study aimed to assess the V̇O2 uptake obtained during a GXT and subsequent verification phase in untrained participants in a hot environment. Methods: Twelve sedentary males completed a GXT followed by a biphasic supramaximal-load verification phase in a hot environment (39°C, 32% relative humidity). Rest between tests occurred in a temperate chamber and lasted until gastrointestinal temperature returned to baseline. Results: Mean verification phase V̇O2max (37.8 ± 4.3 mL·kg−1·min−1) was lower than GXT (39.8 ± 4.1 mL·kg−1·min−1; P = 0.03) and not statistically equivalent. Using an individualized analysis approach, only 17% (2/12) of participants achieved a V̇O2 plateau during the GXT. Verification phase confirmed GXT V̇O2max in 100% of participants, whereas the traditional and the new age-dependent secondary V̇O2max criteria indicated GXT V̇O2max achievement at much lower rates (8/12 [67%] vs 7/12 [58%], respectively). Correlational indices between GXT and verification phase V̇O2max were strong (intraclass correlation coefficient = 0.95, r = 0.86), and Bland–Altman analysis revealed a low mean bias of −2.1 ± 1.9 mL·kg−1·min−1 and 95% limits of agreement (−5.8 to 1.7 mL·kg−1·min−1). Conclusions: Very few untrained males achieved a V̇O2 plateau during GXT in the heat. When conducting GXT in a hot condition, the verification phase remains a valuable addition to confirm V̇O2max in untrained males. [ABSTRACT FROM AUTHOR]

Purpose: To determine if the speed–duration relationship is altered with age and sex of elite Master's runners. Methods: The world's top 10 performances for men and women in three events (800, 1500, and 5000 m) across six age groups (18–34 yr, 40–49 yr, 50–59 yr, 60–69 yr, 70–79 yr, and 80–89 yr) were analyzed from public data to establish theoretical models of the speed–duration relationship. Critical speed (CS) and the curvature constant (D ′) were estimated by fitting the average speeds and performance times with a two-parameter hyperbolic model. Results: Critical speed expressed relative to the 18- to 34-yr-olds, declined with age (92.2% [40–49] to 55.2% [80–89]; P < 0.001), and absolute CS was higher in men than women within each age group (P < 0.001). The percent difference in CS between the men and women progressively increased across age groups (10.8% [18–34] to 15.5% [80–89]). D ′ was lower in women than men in the 60–69 yr, 70–79 yr, and 80–89 yr age groups (P < 0.001), but did not differ in the 18–34 yr, 40–49 yr, or 50–59 yr age groups. Conclusions: Critical speed progressively decreased with age, likely due to age-related decrements in several physiological systems that cause reduced aerobic capacity. The mechanism for the larger sex difference in CS in the older age groups is unknown but may indicate physiological differences that occur with aging and/or historical sociological factors that have reduced participation opportunities of older female runners resulting in a more limited talent pool. [ABSTRACT FROM AUTHOR]

Soccer physical preparation has been extensively researched with previous emphasis on high-intensity interval running and small-sided games. However, neither approach considers positional differences. The purpose of this study was to investigate the feasibility and short-term effects of a novel position-specific conditioning training (PSCT) paradigm on physical and technical abilities of young soccer players. Fifteen male Vietnamese professional youth soccer players (16.1 ± 0.4 years, 171.7 ± 4.8 cm, 63.9 ± 3.8 kg) undertook a 3-week control period followed by a 3-week intervention with PSCT drills performed twice per week. Position-specific conditioning training comprised purposely designed drills for attackers, defenders, and wingers, respectively. The intensity and duration were the same for all drills (4 × 4 minutes at ∼90% heart rate maximum [HRmax], separated by a 4-minute recovery at 70% HRmax) but differed in the technical and tactical actions performed. Outcome measures included Yo-Yo intermittent recovery test level 1, repeated sprint ability, 10-m and 30-m sprint time, and the Loughborough Soccer Passing Test for technical skills in a fatigued and nonfatigued state. Position-specific conditioning training drills induced a desirable intensity for effective conditioning purpose (89.0 ± 2.1% HRmax) with low interplayer variability (coefficient of variation = 2.4%). Yo-Yo intermittent recovery test level 1 performance improved (p < 0.05) after the control (Δ178.7 ± 203.3 m) and intervention (Δ176.0 ± 225.7 m) periods without a difference between. These results confirmed the feasibility of PSCT as a novel high-intensity training approach for soccer players. Improvements in aerobic capacity were noted, despite no effect on other physical and technical measures. PSCT may be suitable for individual training, return-to-play stages of rehabilitation, during off-season, or in academy settings when time is not a constraint. [ABSTRACT FROM AUTHOR]

Heart failure with preserved ejection fraction (HFpEF) is one of the most common forms of heart failure; its prevalence is increasing, and outcomes are worsening. Affected patients often experience severe exertional dyspnea and debilitating fatigue, as well as poor quality of life, frequent hospitalizations, and a high mortality rate. Until recently, most pharmacological intervention trials for HFpEF yielded neutral primary outcomes. In contrast, trials of exercise-based interventions have consistently demonstrated large, significant, clinically meaningful improvements in symptoms, objectively determined exercise capacity, and usually quality of life. This success may be attributed, at least in part, to the pleiotropic effects of exercise, which may favorably affect the full range of abnormalities—peripheral vascular, skeletal muscle, and cardiovascular—that contribute to exercise intolerance in HFpEF. Accordingly, this scientific statement critically examines the currently available literature on the effects of exercise-based therapies for chronic stable HFpEF, potential mechanisms for improvement of exercise capacity and symptoms, and how these data compare with exercise therapy for other cardiovascular conditions. Specifically, data reviewed herein demonstrate a comparable or larger magnitude of improvement in exercise capacity from supervised exercise training in patients with chronic HFpEF compared with those with heart failure with reduced ejection fraction, although Medicare reimbursement is available only for the latter group. Finally, critical gaps in implementation of exercise-based therapies for patients with HFpEF, including exercise setting, training modalities, combinations with other strategies such as diet and medications, long-term adherence, incorporation of innovative and more accessible delivery methods, and management of recently hospitalized patients are highlighted to provide guidance for future research. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to assess the effects of 20 wk resistance exercise training with or without protein supplementation on body composition, muscle mass, muscle strength, physical performance, and aerobic capacity in prostate cancer patients receiving androgen deprivation therapy (ADT). Methods: Sixty prostate cancer patients receiving ADT were randomly assigned to perform 20 wk of resistance exercise training with supplementation of 31 g whey protein (EX + PRO, n = 30) or placebo (EX + PLA, n = 30), consumed immediately after exercise and every night before sleep. A separate control group (CON, n = 36) only received usual care. At baseline and after 20 wk, body composition (dual-energy x-ray absorptiometry), muscle mass (computed tomography scan), muscle strength (1-repetition maximum strength tests), physical performance (Timed Up and Go Test, 30-Second Chair Stand Test, and Stair Climb Test), aerobic capacity (cardiopulmonary exercise test), and habitual dietary intake (food diary) were assessed. Data were analyzed using a two-factor repeated-measures ANOVA. Results: Over time, muscle mass and strength increased in EX + PRO and EX + PLA and decreased in CON. Total fat mass and fat percentage increased in EX + PRO and CON, but not in EX + PLA. Physical performance did not significantly change over time in either group. Aerobic capacity was maintained in EX + PLA, but it decreased in EX + PRO and CON. Habitual protein intake (without supplements) averaged >1.0 g·kg body weight−1·d−1, with no differences over time or between groups. Conclusions: In prostate cancer patients, resistance exercise training counteracts the adverse effects of ADT on body composition, muscle mass, muscle strength, and aerobic capacity, with no additional benefits of protein supplementation. [ABSTRACT FROM AUTHOR]

Digby, L, McCarthy, SF, Bornath, DPB, Copeland, JL, and Hazell, TJ. Individual and group responses of cardiorespiratory fitness to running and cycling sprint interval training. J Strength Cond Res 37(4): e313–e316, 2023—Sprint interval training (SIT) has gained popularity as an effective way to improve peak oxygen consumption (V̇O2peak) and subsequently health in a time-efficient manner. In addition, SIT has demonstrated improvements of ∼5–12% in V̇O2peak for both running and cycling protocols, although comparisons of differing modalities have yet to be examined. Therefore, this study sought to determine group and individual responses to running and cycling SIT while examining any crossover effects of running and cycling SIT when V̇O2peak is tested in different modes of exercise where 18 subjects completed either 3 weeks of cycling SIT (6 male, 3 female) or running SIT (5 male, 4 female) consisting of 4–6 repeated 30-second all-out bouts interspersed with 240 seconds of recovery. Cycling and running V̇O2peak tests were completed pretraining and post-training for the investigation of mode-specific cardiorespiratory fitness improvements. There were main effects of time for cycling V̇O2peak (P = 0.022, η p 2 = 0.499) and running V̇O2peak (P = 0.080, η p 2 = 0.334) that seem greater when testing in the same mode as training (∼+5.5%). A similar proportion of responders were identified in both training modes (∼67%) suggesting running and cycling SIT are both effective for improving cardiorespiratory fitness. These results suggest that the specificity of testing and training are important for SIT and that both running and cycling SIT are similarly effective at improving V̇O2peak. [ABSTRACT FROM AUTHOR]

Police officers are required to perform physically demanding occupational tasks and, as such, require an adequate level of fitness. The aim of this study was to investigate relationships between a physical fitness assessment test (PAT) and a task-specific physical competency test (PCT). Retrospective data for 307 police trainees who completed the PAT and the PCT were provided. The PAT comprised a 2.4-km run, vertical jump, push-ups, and grip strength measures. The PCT, a single timed event, consisted of 10 occupational specific tasks (e.g., trailer push, wall climb, window climb through), which were completed within a 400-m obstacle course. Pearson's correlations were used to investigate relationships between the PAT and the PCT. Linear regression analyses were conducted to determine whether PAT predicted PCT performance. All PAT measures significantly correlated with PCT performance with the strength of the correlations ranging from moderate (vertical jump; r = -0.420, p < 0.01) to strong (2.4 km run; r = 0.639, p < 0.01). The highest predictive relationship was observed with 2.4-km run (r² = 0.409), and the lowest predictive relationship was observed with the vertical jump (r² = 0.177). The results of this study highlight the importance of aerobic capacity (2.4 km run), muscular endurance (push-ups), strength (grip strength), and power (vertical jump) for successful performance during the PCT. These physical attributes should be developed in new police trainees before attending recruit training if viable and form part of any return-to-work reconditioning frameworks for both police trainees and officers. [ABSTRACT FROM AUTHOR]

Purpose: Maximal oxygen uptake (V ̇ O 2 max ) is the criterion measure of cardiorespiratory fitness. Lower cardiorespiratory fitness is a strong predictor of poor health outcomes, including all-cause mortality. Because V ̇ O 2 max testing is resource intensive, several non–exercise-based V˙O2max prediction equations have been published. We assess these equations' ability to predict measured V˙O2max, recalibrate these equations, and quantify the association of measured and predicted V˙O2max with all-cause mortality. Methods: Baltimore Longitudinal Study of Aging participants with valid V˙O2max tests were included (n = 1080). Using published V˙O2max prediction equations, we calculated predicted V˙O2max and present performance metrics before and after recalibration (deriving new regression estimates by regressing measured V˙O2max on Baltimore Longitudinal Study of Aging covariates). Cox proportional hazards models were fit to quantify associations of measured, predicted, and recalibration-predicted values of V˙O2max with mortality. Results: Mean age and V˙O2max were 69.0 ± 10.4 yr and 21.6 ± 5.9 mL·kg−1·min−1, respectively. The prediction equations yielded root mean square error values ranging from 4.2 to 20.4 mL·kg−1·min−1. After recalibration, these values decreased to 3.9–4.2 mL·kg−1·min−1. Adjusting for all covariates, all-cause mortality risk was 66% lower for the highest quartile of measured V˙O2max relative to the lowest. Predicted V˙O2max variables yielded similar estimates in unadjusted models but were not robust to adjustment. Conclusions: Measured V˙O2max is an extremely strong predictor of all-cause mortality. Several published V˙O2max prediction equations yielded the following: 1) reasonable performance metrics relative to measured V˙O2max especially when recalibrated, and 2) all-cause mortality hazard ratios similar to those of measured V˙O2max, especially when recalibrated, yet 3) were not robust to adjustment for basic demographic covariates likely because these were used in the equation for predicted V˙O2max. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of recombinant human erythropoietin (rHuEPO) administration on exercise endurance, maximal aerobic performance, and total hemoglobin mass (tHb). We hypothesized that frequent, small intravenous injections of epoetin β would increase time trial performance, peak oxygen uptake (V̇O2peak), and tHb in both males and females. Methods: We included 48 healthy, recreational to trained males (n = 24, mean ± SD V̇O2peak = 55 ± 5 mL O2·kg−1⋅min−1) and females (n = 24; V̇O2peak of 46 ± 4 mL O2·kg−1⋅min−1) in a counterbalanced, double-blind, randomized, placebo-controlled study design stratified by sex. Time trial performance, V̇O2peak, and tHb were determined before and after intravenous injections of either rHuEPO (9 IU·kg bw−1 epoetin β) or saline (0.9% NaCl) three times weekly for 4 wk. Results: A time–treatment effect (P < 0.05) existed for time trial performance. Within the rHuEPO group, mean power output increased by 4.1% ± 4.2% (P < 0.001). Likewise, a time–treatment effect (P < 0.001) existed for V̇O2peak, where the rHuEPO group improved V̇O2peak and peak aerobic power by 4.2% ± 6.1% (P < 0.001) and 2.9% ± 4.0% (P < 0.01), respectively. A time–treatment effect (P < 0.001) existed for tHb, where the rHuEPO group increased tHb by 6.7% ± 3.4% (P < 0.001). A main effect of "sex" alone was also evident (P < 0.001), but no sex-specific interactions were found. No changes were observed in the placebo group for mean power output, V̇O2peak, peak aerobic power, or tHb. Conclusions: Microdoses with intravenous rHuEPO provide a sufficient erythropoietic stimuli to augment tHb and enhance aerobic-dominated performance in both trained males and females. [ABSTRACT FROM AUTHOR]

Purpose: Several studies have shown a lower risk of developing frailty with long-term higher levels of physical activity. However, most these studies lacked repeated measurement over the follow-up period. Therefore, we examined the association between different types of physical activity and in frailty development using repeated measurements. Methods: A total of 69,642 nonfrail women 60 yr and older from the Nurses' Health Study were followed from 1992 to 2016. Leisure time physical activity was assessed biennially. Frailty was defined as having 3+ of the following five criteria from the FRAIL scale: fatigue, low strength, reduced aerobic capacity, having ≥5 illnesses, and ≥5% weight loss. Cox models adjusted for potential confounders were used to estimate hazard ratios (HR) and 95% confidence interval (CI) for the association between total, moderate-intensity physical activity, vigorous-intensity physical activity, walking, and incident frailty. Results: During 24 yr of follow-up, we documented 16,479 incident frailty cases. Comparing top to bottom quintiles of MET-hours per week of physical activity, the HR was 0.48 (95% CI = 0.45–0.50) for total physical activity, 0.51 (0.48–0.54) for moderate, and 0.75 (0.71–0.79) for vigorous activity (P trend <0.001 for all activities). For each hour per week increase, HR was 0.56 (0.53–0.58), 0.51 (0.48–0.54), and 0.63 (0.58–0.68) for total, moderate, and vigorous activity, respectively. Walking was the most common activity, and each hour per day increase in walking was associated with an HR of 0.41 (0.38–0.44) for frailty incidence; this was evident even among those older than 70 yr and those with preexisting frailty characteristics. Conclusions: Both moderate and vigorous physical activities were associated with a lower risk of frailty. In particular, walking, a broadly accessible activity, was also associated with lower risk. [ABSTRACT FROM AUTHOR]

Background: Exercise intolerance is a defining characteristic of heart failure with preserved ejection fraction (HFpEF). A marked rise in pulmonary capillary wedge pressure (PCWP) during exertion is pathognomonic for HFpEF and is thought to be a key cause of exercise intolerance. If true, acutely lowering PCWP should improve exercise capacity. To test this hypothesis, we evaluated peak exercise capacity with and without nitroglycerin to acutely lower PCWP during exercise in patients with HFpEF. Methods: Thirty patients with HFpEF (70+/-6 years of age; 63% female) underwent 2 bouts of upright, seated cycle exercise dosed with sublingual nitroglycerin or placebo control every 15 minutes in a single-blind, randomized, crossover design. PCWP (right heart catheterization), oxygen uptake (breath x breath gas exchange), and cardiac output (direct Fick) were assessed at rest, 20 Watts (W), and peak exercise during both placebo and nitroglycerin conditions. Results: PCWP increased from 8+/-4 to 35+/-9 mm Hg from rest to peak exercise with placebo. With nitroglycerin, there was a graded decrease in PCWP compared with placebo at rest (-1+/-2 mm Hg), 20W (-5+/-5 mm Hg), and peak exercise (-7+/-6 mm Hg; drug x exercise stage P =0.004). Nitroglycerin did not affect oxygen uptake at rest, 20W, or peak (placebo, 1.34+/-0.48 versus nitroglycerin, 1.32+/-0.46 L/min; drug x exercise P =0.984). Compared with placebo, nitroglycerin lowered stroke volume at rest (-8+/-13 mL) and 20W (-7+/-11 mL), but not peak exercise (0+/-10 mL). Conclusions: Sublingual nitroglycerin lowered PCWP during submaximal and maximal exercise. Despite reduction in PCWP, peak oxygen uptake was not changed. These results suggest that acute reductions in PCWP are insufficient to improve exercise capacity, and further argue that high PCWP during exercise is not by itself a limiting factor for exercise performance in patients with HFpEF. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04068844. What Is New? * Sublingual nitroglycerin reduced exercise pulmonary capillary wedge pressure (PCWP) in patients with heart failure with preserved ejection fraction. * At a fixed 20W exercise work rate, nitroglycerin decreased PCWP by 5 mm Hg, whereas at peak exercise, PCWP decreased by 7 mm Hg. * Despite the reduction in PCWP, functional capacity (peak VO2) did not improve. What Are the Clinical Implications? * Acute reductions in PCWP are insufficient to improve exercise capacity in patients with heart failure with preserved ejection fraction. * These results suggest that high PCWP during exercise is not by itself a limiting factor for exercise performance in patients with heart failure with preserved ejection fraction. [ABSTRACT FROM AUTHOR]

Several studies have highlighted the increased risk of cardiovascular diseases (CVDs) among police officers. Given the longitudinal association between cardiorespiratory fitness (CRF) in early adulthood and later appearance of CVD, the identification of police recruits exhibiting lower CRF could allow the implementation of targeted CVD prevention strategies. Unfortunately, norm-referenced values for the CRF of Canadian police recruits are not yet available. Thus, this research aimed to provide norm-referenced values for the CRF of police recruits in the province of Quebec (Canada) and to evaluate the temporal trend in the CRF of police recruits over a 14-year period. First, a model was developed to estimate maximal oxygen consumption (V̇O2max) based on the results of the physical ability test (PAT) used for the recruitment of police officers in Quebec. Based on the previously developed model, the CRF of police recruits who completed the PAT from 2004 to 2017 was retrospectively assessed using administrative records. The analysis of 7,234 PAT results including 2,150 females (29.7%) and 5,084 males (70.3%) suggests that police recruits generally present high levels of CRF with an average estimated V̇O2max of 53.3 ml·min-1·kg-1 for males and 43.8 ml·min-1·kg-1 for females. Furthermore, our analyses showed significant but small positive correlations between estimated V̇O2max and time periods of PAT performance for male (rs = 0.105, p < 0.001) and female recruits (rs = 0.125, p < 0.001). Overall, our results suggest that the CRF of police recruits in Quebec is considerably higher than that of their North American peers. [ABSTRACT FROM AUTHOR]