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Volume 32 (2024): Issue 4 (Aug 2024)

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Volume 36 (2024): Issue 3 (Aug 2024)

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Caffeine Abstinence in Habituated Users: Cardiovascular Responses to Exercise With Blood Flow Restriction

Matthew A. Chatlaong, Daphney M. Carter, William M. Miller, Chance J. Davidson, and Matthew B. Jessee

Context: Blood flow restriction resistance exercise studies often require caffeine abstinence to avoid cardiovascular effects that could change the blood flow restriction stimulus. However, effects may be attenuated for habituated users. Objective: To compare cardiovascular responses to blood flow restriction resistance exercise when habituated users consume or abstain from caffeine. Design: Thirty participants completed a 3-visit within-subject study beginning with familiarization and caffeine intake questionnaire. Methods: Visits 2 and 3 consisted of blood flow restriction resistance exercise (3 sets bicep curls to failure, 30% 1-repetition max, 40% arterial occlusion pressure [AOP]), following participants’ normal caffeine consumption (CAFF) or abstaining (ABS). AOP, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate were measured preexercise and postexercise. Prevalues and preexercise to postexercise change scores for SBP, DBP, AOP (all millimeters of mercury), heart rate (in beats per minute), and repetitions were compared between conditions. Results are represented as mean (SD). Results: Preexercise AOP was similar for CAFF (137.8 [14.4]) and ABS (137.1 [14.9], BF10 = 0.2), although pre-SBP was higher for CAFF (115.4 [9.8]) than ABS (112.3 [9.4], BF10 = 1.9). Pre-DBP was similar between conditions. The exercise-induced change in AOP was greater for CAFF (18.4 [11.2]) than ABS (13.2 [14.9]), though evidence was anecdotal (BF10 = 0.7). Exercise-induced changes in SBP, DBP, and heart rate were similar between conditions (all BF10 ≤ 0.40). More repetitions were completed for CAFF (63 [26]) than ABS (57 [17], BF10 = 2.1). Conclusions: The findings of this study suggest that for habituated users, maintaining daily caffeine habits will not have substantial effects on common cardiovascular variables relevant to blood flow restriction.

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Effect of Beta-Alanine Supplementation on Maximal Intensity Exercise in Trained Young Male Individuals: A Systematic Review and Meta-Analysis

George D. Georgiou, Kyriaki Antoniou, Stephanie Antoniou, Eleni Anna Michelekaki, Reza Zare, Ali Ali Redha, Konstantinos Prokopidis, Efstathios Christodoulides, and Tom Clifford

Beta-alanine is a nonessential amino acid that is commonly used to improve exercise performance. It could influence the buffering of hydrogen ions produced during intense exercise and delay fatigue, providing a substrate for increased synthesis of intramuscular carnosine. This systematic review evaluates the effects of beta-alanine supplementation on maximal intensity exercise in trained, young, male individuals. Six databases were searched on August 10, 2023, to identify randomized, double-blinded, placebo-controlled trials investigating the effect of chronic beta-alanine supplementation in trained male individuals with an age range of 18–40 years. Studies evaluating exercise performance through maximal or supramaximal intensity efforts falling within the 0.5–10 min duration were included. A total of 18 individual studies were analyzed, employing 18 exercise test protocols and 15 outcome measures in 331 participants. A significant (p = .01) result was observed with an overall effect size of 0.39 (95% confidence interval [CI] [0.09, 0.69]), in favor of beta-alanine supplementation versus placebo. Results indicate significant effects at 4 weeks of supplementation, effect size 0.34 (95% CI [0.02, 0.67], p = .04); 4–10 min of maximal effort, effect size 0.55 (95% CI [0.07, 1.04], p = .03); and a high beta-alanine dosage of 5.6–6.4 g per day, effect size 0.35 (95% CI [0.09, 0.62], p = .009). The results provide insights into which exercise modality will benefit the most, and which dosage protocols and durations stand to provide the greatest ergogenic effects. This may be used to inform further research, and professional or recreational training design, and optimization of supplementation strategies.

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From Exploitative Systems to Exploitative Relationships: A Black Feminist Intervention to Scholarship on Exploitation in College Athletics

Ezinne D. Ofoegbu

This essay introduces interpersonal exploitation in Black women’s relationships in U.S. Division I college athletic environments. Interpersonal exploitation is a Black feminist-oriented analytical frame for exploring how relationships across various levels and systems contribute to the exploitation of Black women and other similarly situated populations in U.S. college athletics. Drawing from existing research, this essay describes how and why scholars, policymakers, and practitioners can use this analytical frame to explore how relationships, and systems that inform these relationships, sustain conditions in which athletes and professionals can be systematically exploited. Addressing exploitation is vital to restore college athletics’ integrity, emphasizing its educational role, and prioritizing well-being.

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How to Equalize High- and Low-Intensity Endurance Exercise Dose

Pekka Matomäki, Olli-Pekka Nuuttila, Olli J. Heinonen, Heikki Kyröläinen, and Ari Nummela

Purpose: Without appropriate standardization of exercise doses, comparing high- (HI) and low-intensity (LI) training outcomes might become a matter of speculation. In athletic preparation, proper quantification ensures an optimized stress-to-recovery ratio. This review aims to compare HI and LI doses by estimating theoretically the conversion ratio, 1:x, between HI and LI: How many minutes, x, of LI are equivalent to 1 minute of HI using various quantification methods? A scrutinized analysis on how the dose increases in relation to duration and intensity was also made. Analysis: An estimation was conducted across 4 categories encompassing 10 different approaches: (1) “arbitrary” methods, (2) physiological and perceptual measurements during exercise, (3) postexercise measurements, and comparison to (4a) acute and (4b) chronic intensity-related maximum dose. The first 2 categories provide the most conservative estimation for the HI:LI ratio (1:1.5–1:10), and the third, slightly higher (1:4–1:11). The category (4a) provides the highest estimation (1:52+) and (4b) suggests 1:10 to 1:20. The exercise dose in the majority of the approaches increase linearly in relation to duration and exponentially in relation to intensity. Conclusions: As dose estimations provide divergent evaluations of the HI:LI ratio, the choice of metric will have a large impact on the research designs, results, and interpretations. Therefore, researchers should familiarize themselves with the foundations and weaknesses of their metrics and justify their choice. Last, the linear relationship between duration and exercise dose is in many cases assumed rather than thoroughly tested, and its use should be subjected to closer scrutiny.

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The Influence of Psychological Factors on Physical Activity in Individuals With Patellofemoral Pain

Timothy J. Gilgallon, Sungwan Kim, and Neal R. Glaviano

Context: Patellofemoral pain (PFP) is a prevalent chronic condition characterized by retropatellar or peripatellar pain exacerbated by various knee flexion-based activities. Previous research has highlighted the impact of psychological constructs on pain and function in chronic musculoskeletal pain conditions, yet their influence on physical activity in PFP cohorts remains unexplored. We aimed to evaluate whether pain self-efficacy and pain catastrophizing predict variations in steps per day and moderate to vigorous physical activity (MVPA) among individuals with PFP. Design: Cross-sectional observational study. Methods: Thirty-nine participants (11 males) with PFP were included. Dependent variables were steps per day and minutes of MVPA. Independent variables were pain self-efficacy and pain catastrophizing, measured by the pain self-efficacy questionnaire and the pain catastrophizing scale. Participants were given an ActiGraph wGT3X-BT for 7 days to assess physical activity. Correlations were assessed between psychological measures and physical activity, and a simple linear regression was performed on psychological variables that correlated with physical activity. Alpha was set a priori at P < .05. Results: Pain self-efficacy scores displayed a moderate association with steps per day (rho = .45, P = .004) and a weak association with MVPA (rho = .38, P = .014). Pain catastrophizing scores exhibited no significant associations with physical activity (P < .05). Regression models affirmed pain self-efficacy scores as significant predictors of both steps per day (F 1,37 = 10.30, P = .002) and MVPA (F 1,37 = 8.98, P = .004). Conclusions: Psychological measures continue to demonstrate value to clinicians treating PFP. Pain self-efficacy scores were moderately associated with steps per day and weakly associated with MVPA, explaining nearly a fifth of the variation in physical activity. Clinicians should prioritize the assessment of pain self-efficacy when treating individuals with PFP, potentially employing psychological interventions to improve physical activity in the PFP population.

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Isokinetic Peak Torque Improvement and Shoulder Muscle Ratios Imbalance Correction After Specific Strength Training on a New Ballistic Throwing Device: A Randomized Controlled Trial

Brahim Agrebi, Wissem Dhahbi, Hatem Abidi, Sofien Kasmi, Narjes Houas, Mokhtar Chtara, and Karim Chamari

Context: The aim of this study was to investigate the effects of 8-week ballistic-strength-training program using a validated specific throwing device (ie, Arm/Shoulder Specific Strength Device), on isokinetic shoulders’ rotation muscle-torques and ratios as well as range of motion in team handball players. Design: A repeated-measures experimental design with a randomized controlled trial was used. Methods: Twenty-six high-level competitive male U-19 team handball players were randomly assigned into training (TG, n = 15) and control (n = 11) groups. The TG undertook a twice a week for 8-week periodized throws program with an individually predetermined optimal load. The program incorporated shackled eccentric and concentric exercises using the Arm/Shoulder Specific Strength Device. Peak torques, functional, and conventional ratios for both arms at different angular velocities (60°·s−1, 180°·s−1, and 300°·s−1) were assessed over time and between groups, using an isokinetic dynamometer. Results: A significant improvement for TG (P < .01; d = 1.13 [moderate]; +20.2%) of the concentric peak torques for dominant arm in external rotation was observed at 300°·s−1. Significant (P < .05–.01) increases were also noted for nondominant arm at the 3 studied angular velocities. In addition, 300°·s−1 eccentric peak torques of the dominant arm and nondominant arm have significantly improved for both external and internal rotations (P < .05; d = .99 [moderate] and d = 1.21 [large]; +15.7% and + 17.9%, respectively) with small changes at the other angular assessed velocities. Posttraining, TG’s dominant arm showed significant improvements (P < .05–.01) in functional and conventional ratios at all velocities. Notably, significant differences (P < .05–.01) were observed at 60°·s−1 and across all velocities when comparing the TG with the control group. TG showed significant increase for internal rotation and external rotation shoulder range of motions (P < .05; d = 1.22–1.27 [large]), +5.0% and +7.7%, respectively). Conclusions: The specific 8-week throwing training program on the Arm/Shoulder Specific Strength Device showed significant performance improvements in almost all assessed isokinetic concentric and eccentric peak torques as well as internal and external range of motion increase for both arms while ensuring rotator cuff torque ratios and shoulder mobility in team handball real sport-specific condition.

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Reliability of Ultrasound Assessment of Hamstring Morphology, Quality, and Stiffness Among Healthy Adults and Athletes: A Systematic Review

Maria Belinda Cristina C. Fidel, Charidy S. Ramos, Donald G. Manlapaz, Helen Banwell, and Consuelo B. Gonzalez-Suarez

Context: The incidence and recurrence rate of hamstring strain injuries remain persistently high, with recurrent injuries leading to increased time lost during play and extended recovery periods compared with initial injury. Ultrasound imaging assesses important factors such as hamstring fascicle length (FL), pennation angle (PA), cross-sectional area (CSA), muscle thickness (MT), echo intensity (EI), and shear wave elastography (SWE), all impacting athletic performance. However, its reliability must be established before employing any measurement tool in research or clinical settings. Objectives: To determine the reliability and measurement error of ultrasound for assessing hamstring FL, PA, CSA, MT, EI, and SWE among healthy adults and athletes; to synthesize the information regarding the operationalization of ultrasound. Evidence Acquisition: A systematic literature search was done from January 1990 to February 5, 2023, to identify reliability and validity studies of hamstring ultrasound assessment published in peer-reviewed journals with identifiable methodology of outcome measures. Evidence Synthesis: Intraclass correlation coefficient measurement of 14 included studies reported moderate to excellent intrarater, interrater, and test–retest reliabilities of FL, PA, and MT regardless of the site of muscle testing, probe size, and setting, state of muscle, and use of different techniques in the extrapolation of FL. Good to excellent test–retest reliability rates for all hamstring anatomic CSA along midmuscle and different percentages of thigh length using panoramic imaging. Good intrarater reliability of EI regardless of gender and orientation of the probe but with excellent intrarater reliability in transverse scan using maximum region of interest. Good intrarater, interrater, and interday repeatability on SWE with the muscle in a stretched position. Conclusion: Evidence from studies with a predominantly low risk of bias shows that ultrasound is a reliable tool to measure hamstring FL, PA, CSA, MT, EI, and SWE in healthy adults and athletes under various experimental conditions.

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Test–Retest Reliability and Visual Perturbation Performance Costs During 2 Reactive Agility Tasks

Ellen M. Smith, David A. Sherman, Samantha Duncan, Andy Murray, Meredith Chaput, Amanda Murray, David M. Bazett-Jones, and Grant E. Norte

Context: High secondary injury rates after orthopedic surgeries have motivated concern toward the construct validity of return-to-sport test batteries, as it is evident that common strength and functional assessments fail to elicit pertinent behaviors like visual search and reactive decision making. This study aimed to establish the test–retest reliability of 2 reactive agility tasks and evaluate the impact of visual perturbation on physical performance. Methods: Fourteen physically active individuals completed 2 agility tasks with reaction time (ie, 4 corner agility), working memory, and pathfinding (ie, color recall) components. Participants completed both tasks 4 times in 2 sessions scheduled 7 days apart. Outcomes included performance metrics of reaction time, time to target, number of targets, and total time assessed with reactive training timing gates. To assess test–retest reliability, we used intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC). Stroboscopic goggles induced visual perturbation during the fourth trial of each task. To assess the effect of visual perturbation, we used paired t tests and calculated performance costs. Results: The 4-corner agility task demonstrated excellent reliability with respect to reaction time (ICC3,1 = .907, SEM = 0.13, MDC = 0.35 s); time to light (ICC3,1 = .935, SEM = 0.07, MDC = 0.18 s); and number of lights (ICC3,1 = .800, SEM = 0.24, MDC = 0.66 lights). The color recall task demonstrated good-to-excellent test–retest reliability for time to lights (ICC3,1 = .818–.953, SEM = 0.07–0.27, MDC = 0.19–0.74 s); test time (ICC3,1 = .969, SEM = 5.43, MDC = 15.04 s); and errors (ICC3,1 = .882, SEM = 0.19, MDC = 0.53 errors). Visual perturbation resulted in increased time to target (P = .022–.011), number of targets (P = .039), and total test time (P = .013) representing moderate magnitude degradation of performance (d = 0.55–0.87, performance costs = 5%–12%). Conclusions: Both tasks demonstrated acceptable test–retest reliability. Performance degraded on both tasks with the presence of visual perturbation. These results suggest standardized reactive agility tasks are reliable and could be developed as components of dynamic RTS testing.