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Philip D Chilibeck,1 Mojtaba Kaviani,2 Darren G Candow,3 Gordon A Zello4 1College of Kinesiology, University of Saskatchewan, Saskatoon, SK, 2School of Nutrition and Dietetics, Acadia University, Wolfville, NS, 3Faculty of Kinesiology and Health Studies, University of Regina, Regina, 4College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada Abstract: The loss of muscle mass and strength with aging results in significant functional impairment. Creatine supplementation has been used in combination with resistance training as a strategy for increasing lean tissue mass and muscle strength in older adults, but results across studies are equivocal. We conducted a systematic review and meta-analysis of randomized controlled trials of creatine supplementation during resistance training in older adults with lean tissue mass, chest press strength, and leg press strength as outcomes by searching PubMed and SPORTDiscus databases. Twenty-two studies were included in our meta-analysis with 721 participants (both men and women; with a mean age of 57–70 years across studies) randomized to creatine supplementation or placebo during resistance training 2–3 days/week for 7–52 weeks. Creatine supplementation resulted in greater increases in lean tissue mass (mean difference =1.37 kg [95% CI =0.97–1.76]; p

Creatine (Cr) supplementation increases muscle mass, strength, and power. Arginine [alpha]-ketoglutarate (A-AKG) is a precursor for nitric oxide production and has the potential to improve blood flow and nutrient delivery (i.e., Cr) to muscles. This study compared a commercial dietary supplement of Cr, A-AKG, glutamine, taurine, branched-chain amino acids, and medium-chain triglycerides with Cr alone or placebo on exercise performance and body composition. Thirty-five men (~23 yr) were randomized to Cr + A-AKG (0.1 g · kg[-1] · d[-1] Cr + 0.075 g · kg[-1] · d[-1] A-AKG, n = 12), Cr (0.1 g · kg[-1] · d[-1], n = 11), or placebo (1 g · kg[-1] · d[-1] sucrose, n = 12) for 10 d. Body composition, muscle endurance (bench press), and peak and average power (Wingate tests) were measured before and after supplementation. Bench-press repetitions over 3 sets increased with Cr + A-AKG (30.9 +/- 6.6 --> 34.9 +/- 8.7 reps; p < .01) and Cr (27.6 +/- 5.9 --> 31.0 +/- 7.6 reps; p < .01), with no change for placebo (26.8 +/- 5.0 --> 27.1 +/- 6.3 reps). Peak power significantly increased in Cr + A-AKG (741 +/- 112 --> 794 +/- 92 W; p < .01), with no changes in Cr (722 +/- 138 --> 730 +/- 144 W) and placebo (696 +/- 63 --> 705 +/- 77 W). There were no differences in average power between groups over time. Only the Cr-only group increased total body mass (79.9 +/- 13.0 --> 81.1 +/- 13.8 kg; p < .01), with no significant changes in lean-tissue or fat mass. These results suggest that Cr alone and in combination with A-AKG improves upper body muscle endurance, and Cr + A-AKG supplementation improves peak power output on repeated Wingate tests. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effects of Red Bull energy drink on Wingate cycle performance and muscle endurance. Healthy young adults (N = 15, 11 men, 4 women, 21 ± 5 y old) participated in a crossover study in which they were randomized to supplement with Red Bull (2 mg/kg body mass of caffeine) or isoenergetic, isovolumetric, noncaffeinated placebo, separated by 7 d. Muscle endurance (bench press) was assessed by the maximum number of repetitions over 3 sets (separated by 1-min rest intervals) at an intensity corresponding to 70% of baseline 1-repetition maximum. Three 30-s Wingate cycling tests (load = 0.075 kp/kg body mass), with 2 min recovery between tests, were used to assess peak and average power output. Red Bull energy drink significantly increased total bench-press repetitions over 3 sets (Red Bull = 34 ± 9 vs. placebo = 32 ± 8, P < 0.05) but had no effect on Wingate peak or average power (Red Bull = 701 ± 124 W vs. placebo = 700 ± 132 W, Red Bull = 479 ± 74 W vs. placebo = 471 ± 74 W, respectively). Red Bull energy drink significantly increased upper body muscle endurance but had no effect on anaerobic peak or average power during repeated Wingate cycling tests in young healthy adults. [ABSTRACT FROM AUTHOR]

Alpha-lipoic acid has been found to enhance glucose uptake into skeletal muscle in animal models. Studies have also found that the co-ingestion of carbohydrate along with creatine increases muscle creatine uptake by a process related to insulin-stimulated glucose disposal. The purpose of this study was to determine the effect of alpha-lipoic acid on human skeletal muscle creatine uptake by directly measuring intramuscular concentrations of creatine, phosphocreatine, and adenosine triphosphate when creatine monohydrate was co-ingested with alpha-lipoic acid. Muscle biopsies were acquired from the vastus lateralis m. of 16 male subjects (18-32 y) before and after the experimental intervention. After the initial biopsy, subjects ingested 20 g x d(-1) of creatine monohydrate, 20 g x d(-1) of creatine monohydrate + 100 g x d(-1) of sucrose, or 20 g x d(-1) of creatine monohydrate + 100 g x d(-1) of sucrose + 1000 mg x d(-1) of alpha-lipoic acid for 5 days. Subjects refrained from exercise and consumed the same balanced diet for 7 days. Body weight increased by 2.1% following the nutritional intervention, with no differences between the groups. There was a significant increase in total creatine concentration following creatine supplementation, with the group ingesting alpha-lipoic acid showing a significantly greater increase (p < .05) in phosphocreatine (87.6 --> 106.2 mmol x kg(-1) dry mass [dm]) and total creatine (137.8 --> 156.8 mmol x kg(-1) dm). These findings indicate that co-ingestion of alpha-lipoic acid with creatine and a small amount of sucrose can enhance muscle total creatine content as compared to the ingestion of creatine and sucrose or creatine alone. [ABSTRACT FROM AUTHOR]

Our purpose was to assess muscular adaptations during 6 weeks of resistance training in 36 males randomly assigned to supplementation with whey protein (W; 1.2 g/kg/day), whey protein and creatine monohydrate (WC; 0.1 g/kg/day), or placebo (P; 1.2 g/kg/day maltodextrin). Measures included lean tissue mass by dual energy x-ray absorptiometry, bench press and squat strength (1-repetition maximum), and knee extension/flexion peak torque. Lean tissue mass increased to a greater extent with training in WC compared to the other groups, and in the W compared to the P group (p <.05). Bench press strength increased to a greater extent for WC compared to W and P (p <.05). Knee extension peak torque increased with training for WC and W (p <.05), but not for P. All other measures increased to a similar extent across groups. Continued training without supplementation for an additional 6 weeks resulted in maintenance of strength and lean tissue mass in all groups. Males that supplemented with whey protein while resistance training demonstrated greater improvement in knee extension peak torque and lean tissue mass than males engaged in training alone. Males that supplemented with a combination of whey protein and creatine had greater increases in lean tissue mass and bench press than those who supplemented with only whey protein or placebo. However, not all strength measures were improved with supplementation, since subjects who supplemented with creatine and/or whey protein had similar increases in squat strength and knee flexion peak torque compared to subjects who received placebo. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Randomized controlled trial with repeated measures. OBJECTIVES: To determine the effect of trunk stability training on vertical takeoff velocity. BACKGROUND: Trunk stability training is commonly used in sports training programs; however, the effects of stability training on performance enhancement are not known. Trunk stability training may provide a more stable pelvis and spine from which the leg muscles can generate action, may better link the upper body to the lower body, or may enhance leg muscle activation, thus promoting optimal force production during sporting activities such as a vertical jump. METHODS AND MEASURES: Fifty-five athletes were randomly assigned to 1 of 4 training groups: trunk stability (TS), leg strength (LS), trunk stability and leg strength (TL), and control (CO). Subjects were tested 3 times: at pretraining, after 3 weeks of training, and after 9 weeks of training. A repeated-measures analysis of covariance (ANCOVA) was used to examine differences among groups for vertical takeoff velocity measured indirectly using a force plate. Pretraining takeoff velocity and body mass were used as covariates. RESULTS: After 3 and 9 weeks, the training groups were not different from each other. After 9 weeks of training, all 3 training groups had a greater takeoff velocity than the control group (P<.05). After 3 weeks of training only the TS group had a greater takeoff velocity than the control group (P<.05). Only the TL group increased significantly in vertical takeoff velocity between the third- and ninth-week testing periods (P<.05). CONCLUSIONS: Nine weeks of trunk stability training was similarly effective in enhancing vertical takeoff velocity as leg strength training or the combination of trunk stability and leg strength training. [ABSTRACT FROM AUTHOR]

Muscles exercised before creatine (Cr) supplementation have a greater elevation of intramuscular Cr than nonexercised muscles. PURPOSE: To determine whether preferential increase of muscle thickness could be achieved by ingesting Cr immediately after exercise of specific muscles over 6 wk. Another purpose was to determine if the increase in lean tissue mass (LTM) with Cr supplementation is greater in males than females. METHODS: Subjects randomly assigned to Cr (six males, five females, 0.2 g Cr x kg(-1)) and placebo (PL; five males, five females) performed single-limb training with one side of the body two times per week and with the opposite limbs two times per week. Cr was consumed after training of one side of the body and PL after training the opposite side. Subjects on PL always consumed PL after exercise. Elbow flexors and knee extensors muscle thickness, LTM, fat, and bone mass, and single-limb bench and leg press one-repetition maximum (1-RM) were assessed before and after 6 wk. RESULTS: Within the Cr group, elbow flexors muscle thickness increased more in the limbs trained on days Cr was supplemented compared with limbs trained on days PL was supplemented (P < 0.02). All other measures changed to a similar extent between limbs. Males on Cr had the greatest increase in LTM (P < 0.05) with no difference between females on Cr and PL. Bench press 1-RM increased more in Cr than PL groups (P < 0.01). All other measures changed to a similar extent between groups. Males increased bone mass (P < 0.01) with no effect of Cr supplementation. CONCLUSION: Supplementing with Cr after training of the arms resulted in greater increase in muscle thickness of the arms. Males have a greater increase in LTM with Cr supplementation than females. [ABSTRACT FROM AUTHOR]

Research in animal models indicates that without estrogen, the effectiveness of exercise for increasing bone mineral in females is reduced. With decreased estrogen levels, there is an increase in the threshold at which strains are detected by bone, in turn reducing the transmission of mechanical to biochemical signals for bone formation. Studies combining estrogen replacement and exercise training in postmenopausal women have yielded mixed results but indicate that the combination of interventions may be more effective than either intervention alone for increasing bone mass. Given the continued debate over the risks and benefits of estrogen replacement, other compounds such as bisphosphonates or phytoestrogens may be preferred in combination with exercise training for optimally increasing bone mass and preventing osteoporotic fracture. Studies on animals show that the combination of bisphosphonate or phytoestrogen supplementation with exercise training is effective, but trials in humans are lacking. [ABSTRACT FROM AUTHOR]

PURPOSE: To compare the change in muscle creatine, fiber morphology, body composition, hydration status, and exercise performance between vegetarians and nonvegetarians with 8 wk of creatine supplementation and resistance training. METHODS: Eighteen VG and 24 NV subjects (19-55 yr) were randomly assigned (double blind) to four groups: VG + creatine (VGCr, N=10), VG + placebo (VGPl, N=8), NV + creatine (NVCr, N=12), and NV + placebo (NVPl, N=12). Before and at the end of the study, muscle biopsies were taken from the vastus lateralis m, body composition was assessed by DXA, and strength was assessed using 1-RM bench press and leg press. Subjects participated in the same 8-wk resistance-training program. Creatine dosage was based on lean tissue mass (0.25 g.kg(-1) LTM.d(-1) x 7 d; 0.0625 g.kg(-1) LTM.d(-1) x 49 d). RESULTS: Biopsy samples indicated that total creatine (TCr=free Cr + PCr) was significantly lower in VG compared with NV at baseline (VG=117 mmol.kg(-1); NV=130 mmol.kg(-1); P<0.05). For Cr subjects, there was a greater increase in PCr, TCr, bench-press strength, isokinetic work, Type II fiber area, and whole-body lean tissue compared with subjects on placebo (P<0.05). Vegetarians who took Cr had a greater increase in TCr, PCr, lean tissue, and total work performance than nonvegetarians who took Cr (P<0.05). The change in muscle TCr was significantly correlated with initial muscle TCr, and the change in lean tissue mass and exercise performance. These findings confirm an ergogenic effect of Cr during resistance training and suggest that subjects with initially low levels of intramuscular Cr (vegetarians) are more responsive to supplementation. [ABSTRACT FROM AUTHOR]

Purpose of Review: Osteosarcopenia is an age-related condition characterized by reductions in bone mineral, muscle/lean mass, strength and functional ability which increases the risk of falls, fractures, frailty and premature mortality. One main contributing factor to osteosarcopenia is malnutrition. The purpose was to review recent evidence of creatine monohydrate (CrM) supplementation in older adults and to discuss the potential to manage osteosarcopenia., Recent Findings: Accumulating research shows that CrM supplementation, primarily when combined with exercise training, has the potential to serve as a viable intervention in the management of osteosarcopenia. Collectively, CrM supplementation during exercise training in older adults led to greater improvements in whole-body lean mass, lower-limb muscle density and bone geometry and muscle strength (primarily upper-body) compared to exercise training alone. However, no study has investigated the effects of CrM, with and without exercise training, in older adults with osteosarcopenia., Summary: Given the positive findings of CrM on measures of muscle and bone in healthy older adults, there is potential for CrM to be added as an adjunct to exercise training in the management of osteosarcopenia. However, randomized clinical trials are needed to confirm the safety and efficacy of this nutrient in this clinical population., (Copyright © 2025 Wolters Kluwer Health, Inc. All rights reserved.)

Resistance training (RT) load and volume are considered crucial variables to appropriately prescribe and manage for eliciting the targeted acute responses (i.e., minimizing neuromuscular fatigue) and chronic adaptations (i.e., maximizing neuromuscular adaptations). In traditional RT contexts, load and volume are generally pre-prescribed; thereby, potentially yielding sub-optimal outcomes. A RT concept that individualizes programming is autoregulation: a systematic two-step feedback process involving, (1) monitoring performance and its constituents (fitness, fatigue, and readiness) across multiple time frames (short-, moderate-, and long-term); and (2) adjusting programming (i.e., load and volume) to elicit the targeted goals (i.e., responses and adaptations). A growing body of load and volume autoregulation research has accelerated recently, with several meta-analyses suggesting that autoregulation may provide a small advantage over traditional RT. Nonetheless, the existing literature has typically conceptualized these current autoregulation methods as standalone practices, which has limited their extensive utility in research and applied settings. The primary purpose of this review was three-fold. Initially, we synthesized the current methods of load and volume autoregulation, while disseminating each method's main advantages and limitations. Second, we conceptualized a theoretical Integrated Velocity Model (IVM) that integrates the current methods for a more holistic perspective of autoregulation that may potentially augment its benefits. Lastly, we illustrated how the IVM may be compared to the current methods for future directions and how it may be implemented for practical applications. We hope that this review assists to contextualize a novel autoregulation framework to help inform future investigations for researchers and practices for RT professionals., Competing Interests: Declarations. Ethics approval and consent to participate: N/A. Consent to participate: N/A. Consent for publication: N/A. Conflict of interest: Landyn M. Hickmott and Scotty J. Butcher declare that they have no potential competing interests relevant to the content of this review. Philip D. Chilibeck declares that they are an Editor of the European Journal of Applied Physiology., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Abstract: Leonhardt, TPM, Chilibeck, PD, Ko, J, and Zello, GA. Nutrition knowledge and dietary adequacy in powerlifters. J Strength Cond Res 38(11): 1924-1932, 2024-Athletes competing in weight categories (e.g., powerlifters) often restrict food intake approaching competition, which may be detrimental to health and performance. Our purpose was to assess the effect of nutrition knowledge, sex, and time (off-season versus precompetition, when athletes often cut weight) on dietary adequacy in powerlifters. Twenty-three powerlifters (10 females; 30.7 ± 11.2 years) completed questionnaires to assess nutrition knowledge and dietary adequacy. Athletes with higher nutrition knowledge consumed more fruits and nuts and less vitamin B2, B3 across all time points ( p < 0.05) and a greater number (73%) were above the recommended dietary allowance for vitamin D compared with athletes with lower nutrition knowledge (50%) ( p < 0.05). Male powerlifters with higher nutrition knowledge consumed less alcohol and vitamin A than male powerlifters with lower nutrition knowledge ( p < 0.05). Female powerlifters with higher nutrition knowledge consumed less sugar and beverage calories than female powerlifters with lower nutrition knowledge ( p < 0.05). Intake of alcohol and carbohydrate decreased, and meat calories increased from off-season to precompetition ( p < 0.05). Male powerlifters increased B-vitamins, whereas female powerlifters decreased B-vitamin and sugar consumption approaching competition ( p < 0.05). Male powerlifters increased water consumption versus female powerlifters approaching competition (sex × time, p < 0.05). There was no effect of nutrition knowledge on dietary changes approaching competition. Nutrition knowledge, sex, and competitive season affect dietary intake of powerlifters. A higher nutrition knowledge predicts a higher intake of some foods and nutrients important for health and performance. Female powerlifters should pay close attention to the intake of B-vitamins and water before competitions when many are trying to cut weight., (Copyright © 2024 National Strength and Conditioning Association.)

Background: We estimated the short-term effects of an educational workshop and 10-week outdoor walk group (OWG) compared to the workshop and 10 weekly reminders (WR) on increasing outdoor walking (primary outcome) and walking capacity, health-promoting behavior, and successful aging defined by engagement in meaningful activities and well-being (secondary outcomes) in older adults with difficulty walking outdoors., Methods: In a 4-site, parallel-group randomized controlled trial, two cohorts of community-living older adults (≥ 65 years) reporting difficulty walking outdoors participated. Following a 1-day workshop, participants were stratified and randomized to a 10-week OWG in parks or 10 telephone WR reinforcing workshop content. Masked evaluations occurred at 0, 3, and 5.5 months. We modeled minutes walked outdoors (derived from accelerometry and global positioning system data) using zero-inflated negative binomial regression with log link function, imputing for missing observations. We modeled non-imputed composite measures of walking capacity, health-promoting behavior, and successful aging using generalized linear models with general estimating equations based on a normal distribution and an unstructured correlation matrix. Analyses were adjusted for site, participation on own or with a partner, and cohort., Results: We randomized 190 people to the OWG (n = 98) and WR interventions (n = 92). At 0, 3, and 5.5 months, median outdoor walking minutes was 22.56, 13.04, and 0 in the OWG, and 24.00, 26.07, and 0 in the WR group, respectively. There was no difference between groups in change from baseline in minutes walked outdoors based on incidence rate ratio (IRR) and 95% confidence interval (CI) at 3 months (IRR = 0.74, 95% CI 0.47, 1.14) and 5.5 months (IRR = 0.77, 95% CI 0.44, 1.34). Greater 0 to 3-month change in walking capacity was observed in the OWG compared to the WR group (βz-scored difference = 0.14, 95% CI 0.02, 0.26) driven by significant improvement in walking self-efficacy; other comparisons were not significant., Conclusions: A group, park-based OWG was not superior to WR in increasing outdoor walking activity, health-promoting behavior or successful aging in older adults with difficulty walking outdoors; however, the OWG was superior to telephone WR in improving walking capacity through an increase in walking self-efficacy. Community implementation of the OWG is discussed., Trial Registration: ClinicalTrials.gov NCT03292510 Date of registration: September 25, 2017., (© 2024. The Author(s).)

Nutrient requirements for para-athletes will be influenced by a variety of factors secondary to their impairment and, therefore, recommendations for para-athletes cannot be drawn directly from that of able-bodied athletes. Information on the dietary intakes of para-athletes is lacking and therefore needs to be examined. This study assessed the nutrient intakes and diet quality of 31 paracyclists via food frequency questionnaires. Based on the dietary reference intakes, most paracyclists consumed intakes above the recommended dietary allowance (RDA) or adequate intake (AI). Recommendations were not met for iodine (males = 87% RDA; females = 62% RDA) or fibre in males (84% AI). A 26% risk of inadequacy was noted for vitamins D and E in females. A total of 42% of females and 75% of males did not meet fibre recommendations (14 g/1000 kcal), and only three athletes (all females) consumed fatty acids in the recommended omega-6 to omega-3 ratio of 4:1 or less. Athletes consumed grains, fruits, and vegetables frequently, though whole grains, pulses, and oily fish were generally consumed less often. Paracyclists appear to be consuming intakes at or above recommendations for most nutrients, though several nutrients were consumed below the recommended amounts; therefore, increasing the variety of foods consumed is suggested.

Tart cherries have low glycemic index, antioxidant and anti-inflammatory properties, and therefore may benefit performance and recovery from exercise. We determined the effects of consuming tart cherry juice versus a high-glycemic index sports drink on cycling performance, substrate oxidation, and recovery of low-frequency fatigue. Using a randomized, counter-balanced cross-over design, with one-month washout, 12 recreational cyclists (8 males and 4 females; 35±16y; VO2peak 38.2±7.4 ml/kg/min) consumed cherry juice or sports drink twice a day (300mL/d) for 4d before and 2d after exercise. On the exercise day, beverages (providing 1g/kg carbohydrate) were consumed 45min before 90min of cycling at 65%VO2peak, followed by a 10km time trial. Blood glucose, lactate, carbohydrate and fat oxidation, respiratory exchange ratio (RER), O2 cost of cycling, and rating of perceived exertion (RPE) were measured during the initial 90min of cycling. Muscle soreness, maximal voluntary contraction (MVC) and low-frequency fatigue were determined at baseline and after the time trial on the exercise day, and 30min after beverage consumption 24 and 48h later. There were no differences for time trial performance (17±3min cherry juice vs. 17±2min sports drink, p = 0.27) or any other measures between drink conditions. There were time main effects (p<0.05) for isometric MVC (decreasing) and low-frequency fatigue (increasing; i.e. decreased force at low relative to high stimulation frequencies), changing significantly from baseline to post-exercise and then returning to baseline at 24h post-exercise. Tart cherry juice was not effective for improving performance, substrate oxidation during exercise, and recovery from exercise, compared to a high-glycemic index sports drink., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Gao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Human space exploration expansion from Low-Earth Orbit to deep space is accelerating the need to monitor and address the known health concerns related to deep space radiation. The human musculoskeletal system is vulnerable to these risks (alongside microgravity) and its health reflects the well-being of other body systems. Multiparametric magnetic resonance imaging (MRI) is an important approach for assessing temporal physiological changes in the musculoskeletal system. We propose that ultra-low-field MRI provides an optimal low Size Weight and Power (SwaP) solution for non-invasively monitoring muscle and bone changes on the planned Gateway lunar space station. Our proposed ultra-low-field Gateway MRI meets low SWaP design specifications mandated by limited room in the lunar space station. This review summarizes the current state of our knowledge on musculoskeletal consequences of spaceflight, especially with respect to radiation, and then elaborates how MRI can be used to monitor the deleterious effects of space travel and the efficacy of putative countermeasures. We argue that an ultra-low-field MRI in cis-lunar space on the Gateway can provide valuable research and medical insights into the effects of deep space radiation exposure on astronauts. Such an MRI would also allow the development of imaging protocols that would facilitate Earth-bound teams to monitor space personnel musculoskeletal changes during future interplanetary spaceflight. It will especially have a role in monitoring countermeasures, such as the use of melanin, in protecting space explorers., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Canadian Space Agency (CSA) funding was provided to Pelican MRI, Inc. of which author GES is sole owner., (Copyright © 2024 The Committee on Space Research (COSPAR). Published by Elsevier B.V. All rights reserved.)

Abstract: Hickmott, LM, Butcher, SJ, and Chilibeck, PD. A comparison of subjective estimations and objective velocities at quantifying proximity to failure for the bench press in resistance-trained men and women. J Strength Cond Res 38(7): 1206-1212, 2024-The purpose of this study was to compare the accuracy of quantifying repetitions in reserve (RIR) in the bench press among 18 men and 18 women between 2 conditions: (a) subjective estimations and (b) objective velocities. Subjects performed 4 sessions over 10 days: (a) 1 repetition maximum (1RM) test; (b) repetition-to-failure test at 80% of 1RM; (c) 3 sets to failure at 80% of 1RM; and (d) 3 sets to failure at 75, 80, and 85% of 1RM. During sessions 2, 3, and 4, subjects verbally stated their perceived 4 and 2 RIR intraset, whereas average concentric velocity was recorded on all repetitions. The dependent variable for the subjective estimations condition was the difference between the actual number of RIR and the subject's subjective estimated number of RIR at the verbally stated 4 and 2 RIR. The dependent variable for the objective velocities condition was the difference between the actual number of RIR and the number of RIR calculated from the subject's baseline individualized last repetition average concentric velocity-RIR profile. Significance was set at p ≤ 0.05. Sessions 3 and 4 had significant ( p < 0.001) condition × set and condition × load interactions, respectively, at both 4 and 2 RIR. Objective velocities were significantly more accurate than subjective estimations on set 1 and set 2 at both RIRs during session 3 and for 75 and 80% of 1RM at both RIRs during session 4. Objective velocities exhibit significantly greater accuracy than subjective estimations at quantifying RIR during initial sets and lower loads., (Copyright © 2024 National Strength and Conditioning Association.)

Purpose: Hemp contains protein with high concentrations of the branched-chain amino acids leucine, isoleucine, and valine and oils that have anti-inflammatory properties. Our purpose was to investigate the effects of hemp supplementation during resistance training in trained young adults., Methods: Males (n = 22, 29 ± 8y) and females (n = 12, 30 ± 9y) were randomized (double-blind) to receive 60 g/d of hemp (containing 40 g protein and 9 g oil) or 60 g/d of soy (matched for protein and calories) during eight weeks of resistance training (~  4x/week). Before and after the intervention, participants were assessed for whole-body lean tissue and fat mass (dual-energy X-ray absorptiometry), regional muscle hypertrophy (ultrasound), strength (1-repetition maximum leg press, bench press, biceps curl), voluntary activation (interpolated twitch technique), resting twitch properties (single pulse; 0.5 ms) (before and after a fatigue test), markers of inflammation (Interleukin 6 and C-reactive protein), and bone resorption (urinary N-telopeptides)., Results: Hemp supplementation increased elbow flexor muscle thickness in females (2.6 ± 0.4-3.1 ± 0.5 cm, p = 0.012) while soy supplementation increased elbow flexor muscle thickness in males (3.7 ± 0.4-4.0 ± 0.5 cm, p < 0.01). Twitch torque and rate of torque development were preserved after a fatigue test in males consuming hemp compared to males on soy (p < 0.001)., Conclusion: Overall, hemp provides some sex-specific beneficial effects on measures of muscle accretion and torque under fatiguing conditions in resistance trained young adults., Clinicaltrials: gov Identifier: NCT02529917, registered August 11, 2015., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Proper dietary intake is important for masters athletes because of the physiological changes that occur with aging and the unique nutritional needs when competing at high levels. We evaluated the dietary intake of masters athletes competing at the World Masters Athletics Championships (outdoor games, Tampere, Finland, 2022, and indoor games, Torun, Poland, 2023). A total of 43 athletes (16 females and 27 males, mean age 59.2 ± 10.3 y, height 168 ± 8 cm, and body mass 62.3 ± 10.8 kg) participating in endurance (n = 21), sprint (n = 16), jumping (2), multi-component (e.g., decathlon; n = 3), and throwing (n = 1) events provided 24 h dietary recalls while participating in the games. Carbohydrate intake was below the recommended levels for endurance athletes. Protein intake was below the recommended levels for masters athletes, except for female athletes involved in power events (i.e., sprinters and jumpers). Other nutrient intakes that were below the recommended levels included vitamins D and E, calcium, potassium, vitamin A (except for female endurance athletes), folate (except for female power athletes), vitamin C for female endurance athletes, vitamin K and fiber for males, and zinc for endurance athletes. We conclude that while competing at world championships, many athletes are not consuming the recommended levels of carbohydrates, protein, and micronutrients. Athletes attending these games would benefit from increased nutritional support.

Background: Process evaluations of randomized controlled trials (RCTs) of community exercise programs are important to help explain the results of a trial and provide evidence of the feasibility for community implementation. The objectives of this process evaluation for a multi-centre RCT of outdoor walking interventions for older adults with difficulty walking outdoors, were to determine: 1) implementation fidelity (the extent to which elements of the intervention were delivered as specified in the original protocol) and 2) participant engagement (the receipt of intervention components by the participants) in the Getting Older Adults Outdoors (GO-OUT) trial., Methods: GO-OUT participants attended an active 1-day workshop designed to foster safe, outdoor walking skills. After the workshop, 190 people at 4 sites were randomized to an outdoor walk group (OWG) (n = 98) which met 2x/week for 10 weeks, or the weekly reminders (WR) group (n = 92) which received a phone reminder 1x/week for 10 weeks. The OWG had 5 components - warm-up, continuous distance walk, task-oriented walking activities, 2 nd continuous distance walk, and cool-down. Data on implementation fidelity and participant engagement were gathered during the study through site communications, use of standardized forms, reflective notes of the OWG leaders, and accelerometry and GPS assessment of participants during 2 weeks of the OWG., Results: All sites implemented the workshop according to the protocol. Participants were engaged in all 8 activity stations of the workshop. WR were provided to 96% of the participants in the WR intervention group. The 5 components of the OWG sessions were implemented in over 95% of the sessions, as outlined in the protocol. Average attendance in the OWG was not high - 15% of participants did not attend any sessions and 64% of participants in the OWG attended > 50% of the sessions. Evaluations with accelerometry and GPS during week 3 and 9 OWG sessions suggest that participants who attended were engaged and active during the OWG., Conclusions: This process evaluation helps explain the main study findings and demonstrates the flexibility required in the protocol for safe and feasible community implementation. Future research could explore the use of additional behaviour change strategies to optimize attendance for community implementation., Trial Registration: ClinicalTrials.gov NCT03292510 Date of registration: September 25, 2017., (© 2023. The Author(s).)

Objective: The purpose of this trial is to evaluate the effect of twice-weekly, moderate-to-high intensity progressive resistance training (PRT) for 1 year on lumbar spine bone mineral density (BMD) in individuals with low BMD, compared to attention control. Secondary analyses will examine if resistance training improves other health outcomes; if high intensity is more effective than moderate intensity resistance training for all outcomes; the cost of intervention versus benefit; the willingness to pay; and harms., Methods: For this study, 324 men or postmenopausal women aged ≥50 years with a femoral neck, total hip, or lumbar spine BMD T-score of ≤-1, or a Fracture Risk Assessment Tool probability of ≥20% for major osteoporotic fracture or ≥ 3% for hip fracture are being recruited to participate in a randomized controlled trial with 1:1:1 randomization. Participants will be stratified by site (3 centers) to twice-weekly, supervised PRT at moderate intensity (about 10 repetitions maximum), to high intensity PRT (≤6 repetitions maximum), or to a home posture and balance exercise program (attention control) for 1 year (resistance training to comparator allocation ratio of 2:1). The primary outcome is lumbar spine BMD via dual-energy X-ray absorptiometry. Secondary outcomes include trabecular bone score, proximal femur and total hip BMD and structure, bone-free and appendicular lean mass, physical functioning, falls, fractures, glucose metabolism, cost per life-year gained, adverse events, and quality of life. Between-group differences will be tested in intention-to-treat and per-protocol analyses using analysis of covariance, chi-square tests, or negative binomial or logistic regression, adjusting for site and baseline values., Impact: The Finding the Optimal Resistance Training Intensity For Your Bones trial will support decision making on resistance training for people at risk of fracture., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Physical Therapy Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: Our purpose was to examine the effects of 2 yr of creatine monohydrate supplementation and exercise on bone health in postmenopausal women., Methods: Two hundred and thirty-seven postmenopausal women (mean age, 59 yr) were randomized to receive creatine (0.14 g·kg -1 ·d -1 ) or placebo during a resistance training (3 d·wk -1 ) and walking (6 d·wk -1 ) program for 2 yr. Our primary outcome was the femoral neck bone mineral density (BMD), with lumbar spine BMD and proximal femur geometric properties as the secondary outcomes., Results: Compared with placebo, creatine supplementation had no effect on BMD of the femoral neck (creatine: 0.725 ± 0.110 to 0.712 ± 0.100 g·cm -2 ; placebo: 0.721 ± 0.102 to 0.706 ± 0.097 g·cm -2 ), total hip (creatine: 0.879 ± 0.118 to 0.872 ± 0.114 g·cm -2 ; placebo: 0.881 ± 0.111 to 0.873 ± 0.109 g·cm -2 ), or lumbar spine (creatine: 0.932 ± 0.133 to 0.925 ± 0.131 g·cm -2 ; placebo: 0.923 ± 0.145 to 0.915 ± 0.143 g·cm -2 ). Creatine significantly maintained section modulus (1.35 ± 0.29 to 1.34 ± 0.26 vs 1.34 ± 0.25 to 1.28 ± 0.23 cm 3 (placebo), P = 0.0011), predictive of bone bending strength, and buckling ratio (10.8 ± 2.6 to 11.1 ± 2.2 vs 11.0 ± 2.6 to 11.6 ± 2.7 (placebo), P = 0.011), predictive of reduced cortical bending under compressive loads, at the narrow part of the femoral neck. Creatine reduced walking time over 80 m (48.6 ± 5.6 to 47.1 ± 5.4 vs 48.3 ± 4.5 to 48.2 ± 4.9 s (placebo), P = 0.0008) but had no effect on muscular strength (i.e., one-repetition maximum) during bench press (32.1 ± 12.7 to 42.6 ± 14.1 vs 30.6 ± 10.9 to 41.4 ± 14 kg (placebo)) and hack squat (57.6 ± 21.6 to 84.4 ± 28.1 vs 56.6 ± 24.0 to 82.7 ± 25.0 kg (placebo)). In the subanalysis of valid completers, creatine increased lean tissue mass compared with placebo (40.8 ± 5.7 to 43.1 ± 5.9 vs 40.4 ± 5.3 to 42.0 ± 5.2 kg (placebo), P = 0.046)., Conclusions: Two years of creatine supplementation and exercise in postmenopausal women had no effect on BMD; yet, it improved some bone geometric properties at the proximal femur., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Sports Medicine.)

Skeletal muscle is essential for human locomotion as well as maintaining metabolic homeostasis. Age-related reduction in skeletal muscle mass, strength, and function (i.e., sarcopenia) is a result of pathophysiological processes that include inflammation, alteration of molecular signaling for muscle protein synthesis and degradation, changes in insulin sensitivity, as well as altered skeletal muscle satellite cell activity. Finding strategies to mitigate skeletal muscle loss with age is deemed paramount as the percentage of the population continues to shift towards having more older adults with sarcopenia. Recent research indicates omega-3 fatty acid supplementation can influence anabolic or catabolic pathways in skeletal muscle. Our brief review will provide a synopsis of some underlying mechanisms that may be attributed to omega-3 fatty acid supplementation's effects on skeletal muscle. We will approach this review by focusing on cell culture, animal (pre-clinical models), and human studies evaluating omega-3 fatty acid supplementation, with suggestions for future research. In older adults, omega-3 fatty acids may possess some potential to modify pathophysiological pathways associated with sarcopenia; however, it is highly likely that omega-3 fatty acids need to be combined with other anabolic interventions to effectively ameliorate sarcopenia.

Background: Iron deficiency (ID) is the most prevalent micronutrient deficiency in the world and the leading cause of anemia globally. Female athletes are at a disproportionate risk for ID due to blood loss through menstruation and decreased iron absorption secondary to exercise. Field peas are a rich source of iron but, similar to iron from other plant-based sources, the iron has limited bioavailability due to high levels of phytic acid, an inherent compound that binds to cations, creating a salt (phytate), which limits absorption during digestion. Aim: The purpose of our research was to investigate the effect of a field pea variety bred to have low levels of phytic acid on plasma ferritin, exercise performance, and body composition in female runners. Methods: Twenty-eight female runners (age:34.6  ±  9.7 years; weight: 65.1  ±  8.1 kg; VO 2 max: 50.7  ±  8.9 ml/kg/min) underwent measures of ferritin, exercise performance, and body composition before and after being randomly assigned to consume a powder derived from regular peas, low phytic acid peas, or a non-pea control (maltodextrin), plus vitamin C for 8 weeks. Results: The regular pea and low phytic acid pea groups had a 14.4% and 5.1% increase in plasma ferritin, respectively, while the maltodextrin group had a decrease of 2.2%; however, the difference in changes between groups was not statistically significant. No differences between groups were evident in any of the other measures. Conclusion: Larger doses or longer duration of pea supplementation may be necessary to induce meaningful changes in iron status. This trial was registered at ClinicalTrials.gov (NCT04872140).

Ice hockey players are susceptible to COVID-19 because of close contact and poor arena ventilation. Preventive strategies include reducing arena crowding, practice strategies that reduce clustering of players, at-home rapid tests, symptom screening, and face mask or vaccine recommendations for spectators, coaches, and players. Face masks have little effect on physiological responses or performance and reduce COVID-19 transmission, but shifts should be shortened later in periods to reduce perceived exertion and players should be encouraged to assume a classic "hockey stance" when puck handling to improve peripheral vision. These strategies are important to prevent cancelation of practices or games, which have important physical and psychological benefits., Competing Interests: No conflicts of interest to declare

Background: The number of Masters-level athletes (≥ 35 years of age) taking part in cycling has increased in the past years which may have beneficial effects on their health. The restrictions brought on by the COVID-19 pandemic has the potential to negatively impact the diet, training and fitness of these individuals due to restrictions in place to slow the spread of the virus. Aim: To investigate how the COVID-19 pandemic impacted the diet, training and fitness of Masters-level cyclists. Methods: 32 Masters cyclists (12 males, 20 females; mean age 47 ± 10 years) completed two incremental exercise tests one month apart during the pandemic to assess sport-specific fitness. Participants also completed online questionnaires to report their sedentary behavior and dietary intake before and during the pandemic, and their training volume and intensity for a specified week in February (before the pandemic) and each of March, April and May (during the pandemic). Results: No differences were seen in fitness ( p = 0.6), training volume ( p = 0.24) or intensity ( p = 0.79) and sedentary behavior ( p = 0.14) during the pandemic. Energy intake was unchanged ( p = 1.0) during the pandemic, but participants consumed lower amounts of key nutrients such as fiber, vitamin A, omega-3 fatty acids and potassium ( p < 0.05) while consuming more alcohol ( p = 0.008) and vitamin C ( p = 0.03). Conclusions: Our data shows that the COVID-19 pandemic has undesirable effects on nutrient and alcohol intake of Masters cyclists without impacting their training regimes, which may have adverse effects on their overall health and fitness in the long term.

Sarcopenia refers to the age-related reduction in strength, muscle mass and functionality which increases the risk for falls, injuries and fractures. Sarcopenia is associated with other age-related conditions such as osteoporosis, frailty and cachexia. Identifying treatments to overcome sarcopenia and associated conditions is important from a global health perspective. There is evidence that creatine monohydrate supplementation, primarily when combined with resistance training, has favorable effects on indices of aging muscle and bone. These musculoskeletal benefits provide some rationale for creatine being a potential intervention for treating frailty and cachexia. The purposes of this narrative review are to update the collective body of research pertaining to the effects of creatine supplementation on indices of aging muscle and bone (including bone turnover markers) and present possible justification and rationale for its utilization in the treatment of frailty and cachexia in older adults., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The purpose was to investigate the effects of progressive resistance training (PRT) and creatine supplementation in stroke survivors. Participants were randomized to one of two groups: creatine ( n = 5; 51 ± 16y) or placebo ( n = 3; 73 ± 8y) during 10 weeks of supervised PRT. Prior to and following PRT and supplementation, assessments were made for body composition (lean tissue and fat mass), muscle thickness, muscle strength (1-repetition maximum), functional exercise capacity (6-minute walk test, Berg Balance Scale; BBS), cognition (Montreal Cognitive Assessment; MoCA), and symptoms of anxiety (Generalized Anxiety Disorder Assessment-7; GAD-7) and depression (Center for Epidemiological Studies Depression Scale; CES-D). There were time main effects for leg press strength (increased; p = 0.001), chest press strength (increased; p = 0.003), elbow flexor muscle thickness (increased; p = 0.007), BBS (increased; p = 0.002), MoCA (increased; p = 0.031) and CES-D (decreased; p = 0.045). There was a group x time interaction for the 6 minute walk test ( p = 0.039). The creatine group significantly increased walking distance over time ( p = 0.002) with no change in the placebo group ( p = 0.120). Ten weeks of PRT had some positive effects on measures of muscle strength and size, balance, cognition and depression. The addition of creatine to PRT significantly improved walking performance in stroke survivors.

Sarcopenia negatively affects skeletal muscle mass and function in older adults. Omega-3 (ω-3) fatty acid supplementation, with or without resistance exercise training (RET), is suggested to play a role as a therapeutic component to prevent or treat the negative effects of sarcopenia. A systematic review and meta-analysis were conducted on the impact of ω-3 fatty acid supplementation with or without RET on measures of muscle mass and function in older adults (≥55 y). The data sources included SPORTDiscus, PubMed, and Medline. All the study types involving ω-3 fatty acid supplementation on measures of muscle mass and function in older adults (without disease) were included. The mean differences (MDs) or standardized mean differences (SMDs) with 95% confidence intervals were calculated and pooled effects assessed. Sixteen studies (1660 females, 778 males) met our inclusion criteria and were included in the meta-analysis. ω-3 fatty acid supplementation did not impact lean tissue mass (SMD 0.09 [-0.10, 0.28]). Benefits were observed for lower body strength (SMD 0.54 [0.33, 0.75]), timed-up-and-go (MD 0.29 [0.23, 0.35]s), and 30-s sit-to-stand performance (MD 1.93 [1.59, 2.26] repetitions) but not walking performance (SMD -0.01 [-0.10, 0.07]) or upper body strength (SMD 0.05 [-0.04, 0.13]). Supplementing with ω-3 fatty acids may improve the lower-body strength and functionality in older adults.

Individuals may opt to follow a plant-based diet for a variety of reasons, such as religious practices, health benefits or concerns for animal or environmental welfare. Such diets offer a broad spectrum of health benefits including aiding in the prevention and management of chronic diseases. In addition to health benefits, a plant-based diet may provide performance-enhancing effects for various types of exercise due to high carbohydrate levels and the high concentration of antioxidants and phytochemicals found in a plant-based diet. However, some plant-based foods also contain anti-nutrional factors, such as phytate and tannins, which decrease the bioavailability of key nutrients, such as iron, zinc, and protein. Thus, plant-based diets must be carefully planned to ensure adequate intake and absorption of energy and all essential nutrients. The current narrative review summarizes the current state of the research concerning the implications of a plant-based diet for health and exercise performance. It also outlines strategies to enhance the bioavailability of nutrients, sources of hard-to-get nutrients, and sport supplements that could interest plant-based athletes., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This systematic review examined the effect of Pilates on health-related outcomes in individuals with increased fracture risk to inform the 2021 Clinical Practice Guidelines for Management of Osteoporosis and Fracture Prevention in Canada. Seven electronic databases were searched to December 2020. Studies of Pilates in men and postmenopausal women aged ≥50 years with low bone mineral density (BMD), history of fragility fracture, or moderate-high risk of fragility fracture were included. Two reviewers independently screened studies and performed risk of bias assessment. Of 7286 records and 504 full-text articles, 5 studies were included, encompassing data from 143 participants (99% female). Data were insufficient for meta-analyses. There is low-certainty evidence that Pilates improved physical functioning and health-related quality of life. The effect of Pilates on falls and BMD is uncertain. No evidence was available for the effect of Pilates on mortality, fractures, or adverse events. Overall, Pilates may improve physical functioning and quality of life. Evidence of benefits relative to harms of Pilates in people with increased fracture risk, particularly males, is limited. PROSPERO registration: CRD42019122685. Novelty: Pilates may improve physical functioning and quality of life in women with osteoporosis. Evidence of the effect of Pilates on BMD, falls, fractures, or adverse events is limited.

We summarized the effects of yoga on health-related outcomes and adverse events in men and postmenopausal women ≥50 years-old at increased risk of fracture, to inform the updated Osteoporosis Canada clinical practice guidelines. Six databases were searched for observational studies, randomized controlled trials and case series. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation handbook. Nine studies were included and reported using narrative syntheses due to the limited available evidence. Overall, the available evidence was of very low certainty. There was no effect of yoga on health-related quality of life in randomized trials. Effects on other health-related outcomes were mixed or not available in the literature. Five studies reported no adverse events directly related to the study intervention, and 2 studies did not report whether adverse events occurred. However, 2 case series reported vertebral fractures related to yoga participation, possibly due to excessive spinal flexion. Due to the limited and very low certainty evidence, guideline developers will need to draw indirect evidence from yoga studies among middle aged or older adults that are not at fracture risk. PROSPERO: CRD42019124898. Novelty: Evidence in general was of very low certainty. Yoga had no effect on health-related quality of life in randomized trials. Evidence was mixed or unavailable for other outcomes. Case studies reported yoga poses involving spinal flexion coincided with incidents of vertebral compression fracture among older adults with increased fracture risk.

Background: Autoregulation has emerged as a potentially beneficial resistance training paradigm to individualize and optimize programming; however, compared to standardized prescription, the effects of autoregulated load and volume prescription on muscular strength and hypertrophy adaptations are unclear. Our objective was to compare the effect of autoregulated load prescription (repetitions in reserve-based rating of perceived exertion and velocity-based training) to standardized load prescription (percentage-based training) on chronic one-repetition maximum (1RM) strength and cross-sectional area (CSA) hypertrophy adaptations in resistance-trained individuals. We also aimed to investigate the effect of volume autoregulation with velocity loss thresholds ≤ 25% compared to > 25% on 1RM strength and CSA hypertrophy., Methods: This review was performed in accordance with the PRISMA guidelines. A systematic search of MEDLINE, Embase, Scopus, and SPORTDiscus was conducted. Mean differences (MD), 95% confidence intervals (CI), and standardized mean differences (SMD) were calculated. Sub-analyses were performed as applicable., Results: Fifteen studies were included in the meta-analysis: six studies on load autoregulation and nine studies on volume autoregulation. No significant differences between autoregulated and standardized load prescription were demonstrated for 1RM strength (MD = 2.07, 95% CI - 0.32 to 4.46 kg, p = 0.09, SMD = 0.21). Velocity loss thresholds ≤ 25% demonstrated significantly greater 1RM strength (MD = 2.32, 95% CI 0.33 to 4.31 kg, p = 0.02, SMD = 0.23) and significantly lower CSA hypertrophy (MD = 0.61, 95% CI 0.05 to 1.16 cm 2 , p = 0.03, SMD = 0.28) than velocity loss thresholds > 25%. No significant differences between velocity loss thresholds > 25% and 20-25% were demonstrated for hypertrophy (MD = 0.36, 95% CI - 0.29 to 1.00 cm 2 , p = 0.28, SMD = 0.13); however, velocity loss thresholds > 25% demonstrated significantly greater hypertrophy compared to thresholds ≤ 20% (MD = 0.64, 95% CI 0.07 to 1.20 cm 2 , p = 0.03, SMD = 0.34)., Conclusions: Collectively, autoregulated and standardized load prescription produced similar improvements in strength. When sets and relative intensity were equated, velocity loss thresholds ≤ 25% were superior for promoting strength possibly by minimizing acute neuromuscular fatigue while maximizing chronic neuromuscular adaptations, whereas velocity loss thresholds > 20-25% were superior for promoting hypertrophy by accumulating greater relative volume. Protocol Registration The original protocol was prospectively registered (CRD42021240506) with the PROSPERO (International Prospective Register of Systematic Reviews)., (© 2022. The Author(s).)

Abstract: Downey, RJ, Deprez, DA, and Chilibeck, PD. Effects of postactivation potentiation on maximal vertical jump performance after a conditioning contraction in upper-body and lower-body muscle groups. J Strength Cond Res 36(1): 259-261, 2022-Postactivation potentiation (PAP) involves preperformance contractions that can condition a muscle to enhance subsequent force generation and power output. Our purpose was to examine the effects of conditioning contractions that are specific or nonspecific to the target performance on PAP. Resistance-trained subjects (14 males and 10 females) performed a 7-second isometric contraction involving back squat, bench press (as conditioning contractions), or a control condition (rest) on different days in random order, before maximal vertical jump performance. The back squat as a conditioning contraction increased maximal vertical jump by 1.1 ± 3.0 cm (p < 0.05); however, the bench press as a conditioning contraction unexpectedly reduced maximal vertical jump performance by 1.4 ± 2.7 cm (p < 0.05). Conditioning contractions used to elicit a PAP response should use muscles that are specific to the performance movement. Contractions that are not biomechanically similar to the performance movement may hinder subsequent performance., (Copyright © 2021 National Strength and Conditioning Association.)

Purpose: To examine the efficacy of creatine (Cr) supplementation and any sex differences during supervised whole-body resistance training (RT) on properties of bone and muscle in older adults., Methods: Seventy participants (39 men, 31 women; mean age ± standard deviation: 58 ± 6 yr) were randomized to supplement with Cr (0.1 g·kg-1·d-1) or placebo (Pl) during RT (3 d·wk-1 for 1 yr). Bone geometry (radius and tibia) and muscle area and density (forearm and lower leg) were assessed using peripheral quantitative computed tomography., Results: Compared with Pl, Cr increased or maintained total bone area in the distal tibia (Cr, Δ +17 ± 27 mm2; Pl, Δ -1 ± 22 mm2; P = 0.031) and tibial shaft (Cr, Δ 0 ± 9 mm2; Pl, Δ -5 ± 7 mm2; P = 0.032). Men on Cr increased trabecular (Δ +28 ± 31 mm2; P < 0.001) and cortical bone areas in the tibia (Δ +4 ± 4 mm2; P < 0.05), whereas men on Pl increased trabecular bone density (Δ +2 ± 2 mg·cm-3; P < 0.01). There were no bone changes in the radius (P > 0.05). Cr increased lower leg muscle density (Δ +0.83 ± 1.15 mg·cm-3; P = 0.016) compared with Pl (Δ -0.16 ± 1.56 mg·cm-3), with no changes in the forearm muscle., Conclusions: One year of Cr supplementation and RT had some favorable effects on measures of bone area and muscle density in older adults., (Copyright © 2021 by the American College of Sports Medicine.)

COVID-19 transmission is prevalent during ice-hockey; however, it is unknown whether wearing face masks as a mitigation strategy affects hockey players' performance. We used a randomized cross-over study to compare wearing a surgical mask to a sham mask (control) in youth hockey players (21 males, 5 females, 11.7 ± 1.6 y) during a simulated hockey period (cycle ergometry; six shifts of 20 s of "easy" pedaling (40% peak power), 10 s of "hard" pedaling (95% peak power), 20 s of "easy" pedaling, with shifts separated by 5 min rests). A seventh shift involved two 20 s Wingate tests separated by 40 s rest. Heart rate, arterial oxygen saturation and vastus lateralis tissue oxygenation index (hemoglobin saturation/desaturation) was assessed each shift. On-ice testing was conducted with the maximal Yo-Yo intermittent recovery test. No differences between mask and control conditions for performance were found (Wingate average power: 245 ± 93 vs. 237 ± 93 W, Peak power: 314 ± 116 vs. 304 ± 115 W, on-ice distance: 274 ± 116 vs. 274 ± 110 m) and for heart rate or arterial oxygen saturation during simulated hockey shifts. Tissue oxygenation index was lower from shifts one to six for males ( p < 0.05) and shift seven for females ( p < 0.01) while wearing a mask. Wearing a face mask had no effect on performance in hockey players with only minor effects on muscle oxygenation. ClinicalTrials.gov (NCT04874766) (accessed on 6 May 2021).

Walking is a common activity among older adults. However, the effects of walking on health-related outcomes in people with low bone mineral density (BMD) are unknown. The authors included randomized controlled trials comparing walking to control in individuals aged ≥50 years with low BMD and at risk of fractures. The authors identified 13 randomized controlled trials: nine multicomponent interventions including walking, one that was walking only, and three Nordic walking trials. Most studies had a high risk of bias. Nordic walking may improve the Timed Up-and-Go values (1.39 s, 95% CI [1.00, 1.78], very low certainty). Multicomponent interventions including walking improved the 6-min walk test (39.37 m, 95% CI [21.83, 56.91], very low certainty) and lumbar spine BMD (0.01 g/cm2, 95% CI [0.00, 0.03], low certainty evidence). The effects on quality of life or femoral neck BMD were not significant. There were insufficient data on fractures, falls, or mortality. Nordic walking may improve physical functioning. The effects on other outcomes are less certain; one may need to combine walking with other exercises to be of benefit.

Women with polycystic ovary syndrome (PCOS) exhibit reduced muscle insulin-mediated glucose uptake, potentially attributed to altered muscle mass; however, this is inconclusive. Altered muscle mass may aggravate PCOS complications. Our systematic review and meta-analysis evaluated whether PCOS alters muscle mass and function. Databases (MEDLINE, Web of Science, Scopus) were searched through September 2, 2020, for studies documenting skeletal muscle mass (lean tissue mass) and function (strength) in PCOS and control groups. The primary outcome was total lean body mass (LBM) or fat-free mass (FFM). Data were pooled by random-effects models and expressed as mean differences and 95% confidence intervals. Forty-five studies (n = 3676 participants) were eligible. Women with PCOS had increased total (0.83 [0.08,1.58] kg; p = 0.03; I 2  = 72.0%) yet comparable trunk (0.84 [-0.37,2.05] kg; p = 0.15; I 2  = 73.0%) LBM or FFM versus controls. Results of meta-regression analyses showed no associations between mean differences between groups in total testosterone or homeostatic model assessment of insulin resistance and total or trunk LBM or FFM (All: p ≥ 0.75). Mean differences in body mass index (BMI) were associated with total (0.65 [0.23,1.06] kg; p < 0.01; I 2  = 56.9%) and trunk (0.56 [0.11,1.01] kg; p = 0.02; I 2  = 42.8%) LBM or FFM. The PCOS subgroup with BMI ≥ 25 kg/m 2 had greater total LBM or FFM versus controls (1.58 [0.82,2.34] kg; p < 0.01; I 2  = 64.0%) unlike the PCOS subgroup with BMI < 25 kg/m 2 (-0.45 [-1.94,1.05] kg; p = 0.53; I 2  = 69.5%). Appendicular lean mass and muscle strength data were contradictory and described narratively, as meta-analyses were impossible. Women with PCOS have higher total and trunk lean tissue mass attributed to overweight/obesity, unlike hyperandrogenism or insulin resistance., (© 2021 World Obesity Federation.)

Face masks are promoted for preventing spread of viruses; however, wearing a mask during exercise might increase CO 2 rebreathing, decrease arterial oxygenation, and decrease exercise performance. A systematic review and meta-analysis was conducted on the impact of wearing a mask during exercise. Data sources included SPORTDiscus, PubMed, and Medline. Eligibility criteria included all study designs comparing surgical, N95, or cloth masks to a no mask condition during any type of exercise where exercise performance and/or physiological parameters were evaluated. Healthy and clinical participants were included. Mean differences (MD) or standardized mean differences (SMD) with 95% confidence intervals were calculated and pooled effects assessed. Twenty-two studies involving 1573 participants (620 females, 953 males) were included. Surgical, or N95 masks did not impact exercise performance (SMD -0.05 [-0.16, 0.07] and -0.16 [-0.54, 0.22], respectively) but increased ratings of perceived exertion (SMD 0.33 [0.09, 0.58] and 0.61 [0.23, 0.99]) and dyspnea (SMD 0.6 [0.3, 0.9] for all masks). End-tidal CO 2 (MD 3.3 [1.0, 5.6] and 3.7 [3.0, 4.4] mm Hg), and heart rate (MD 2 [0,4] beats/min with N95 masks) slightly increased. Face masks can be worn during exercise with no influences on performance and minimal impacts on physiological variables. PROSPERO registration: CRD42020224988. Novelty: Face masks can be worn during exercise with no impacts on performance and minimal impacts on physiological variables.