Branched-chain amino acids (BCAA) are one of the most popular sports supplements, marketed under the premise that they enhance muscular adaptations. Despite their prevalent consumption among athletes and the general public, the efficacy of BCAA has been an ongoing source of controversy in the sports nutrition field. Early support for BCAA supplementation was derived from extrapolation of mechanistic data on their role in muscle protein metabolism. Of the three BCAA, leucine has received the most attention because of its ability to stimulate the initial acute anabolic response. However, a substantial body of both acute and longitudinal research has now accumulated on the topic, affording the ability to scrutinize the effects of BCAA and leucine from a practical standpoint. This article aims to critically review the current literature and draw evidence-based conclusions about the putative benefits of BCAA or leucine supplementation on muscle strength and hypertrophy as well as illuminate gaps in the literature that warrant future study.
Daniel L. Plotkin, Kenneth Delcastillo, Derrick W. Van Every, Kevin D. Tipton, Alan A. Aragon, and Brad J. Schoenfeld
Kevin Mercier, Erin Centeio, Alex Garn, Heather Erwin, Risto Marttinen, and John Foley
This study investigated physical education (PE) teachers’ experiences with remote instruction in the United States during the initial outbreak of COVID-19. PE teachers (n = 4,362) from all 50 states completed a survey identifying their experiences with remote instruction in May, 2020. Survey responses were analyzed by geographic region, district type, and school level. Teachers reported having students submit assignments (51% yes), using video instruction (37% yes), being less effective when instructing remotely (20% yes), and emphasizing student outcomes focused on health-related fitness (32% yes), and physical activity value/enjoyment (43% yes). Access to technology (40% yes) and required student assignments (43% yes) were lowest among teachers from the South. Rural teachers reported the least access to technology (37% yes) and rated themselves as least effective (24% yes). Secondary level teachers reported the highest percentage of required assignments (84% yes). Teachers’ responses identify unique challenges to delivering equitable and effective remote PE instruction.
Ed Maunder, Daniel J. Plews, Fabrice Merien, and Andrew E. Kilding
Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P > .05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P < .05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r = .92–.95, P < .05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress.
Bent R. Rønnestad, Sjur J. Øfsteng, Fabio Zambolin, Truls Raastad, and Daniel Hammarström
Purpose: To compare the effects of a 1-week high-intensity aerobic-training shock microcycle composed of either 5 short-interval sessions (SI; n = 9, 5 series with 12 × 30-s work intervals interspersed with 15-s recovery and 3-min recovery between series) or 5 long-interval sessions (LI; n = 8, 6 series of 5-min work intervals with 2.5-min recovery between series) on indicators of endurance performance in well-trained cyclists. Methods: Before and following 6 days with standardized training loads after the 1-week high-intensity aerobic-training shock microcycle, both groups were tested in physiological determinants of endurance performance. Results: From pretraining to posttraining, SI achieved a larger improvement than LI in maximal oxygen uptake (5.7%; 95% confidence interval, 1.3–10.3; P = .015) and power output at a blood lactate concentration of 4 mmol·L−1 (3.8%; 95% confidence interval, 0.2–7.4; P = .038). There were no group differences in changes of fractional use of maximal oxygen uptake at a workload corresponding to a blood lactate concentration of 4 mmol·L−1, gross efficiency, or the 1-minute peak power output from the maximal-oxygen-uptake test. Conclusion: The SI protocol may induce superior changes in indicators of endurance performance compared with the LI protocol, indicating that SI can be a good strategy during a 1-week high-intensity aerobic-training shock microcycle in well-trained cyclists.
Collin A. Webster, Emily D’Agostino, Mark Urtel, Jaimie McMullen, Brian Culp, Cate A. Egan Loiacono, and Chad Killian
In the wake of COVID-19, online physical education (OLPE) has become essential to the sustainability of school physical education programs. The purpose of this article is to consider factors that may be influential in efforts to deliver OLPE to students. The comprehensive school physical activity program model is used to frame a multicomponent conceptualization of OLPE and its goals and outcomes. Central to this framing is the intersectionality of school physical education, the family, and the community. This article provides a platform for physical education teacher educators and researchers to advance OLPE in its support of both the educational and public health benefits of high-quality physical education programs.
Shaun Abbott, Goshi Yamauchi, Mark Halaki, Marcela Torres Castiglioni, James Salter, and Stephen Cobley
Purpose: The study aimed to (1) accurately examine longitudinal relationships between maturity status and both technical skill indices and performance in Australian male (N = 64) age-group Front-crawl swimmers (10–15 y) and (2) determine whether individual differences in maturation influenced relationships between technical skill level and swimming performance. Methods: A repeated-measures design was used to assess maturity status and performance on 200-m Front-crawl trial across 2 competition seasons (2018–2020). Assessments were made on 3 to 5 occasions (median = 3) separated by approximately 4 months. Average horizontal velocity and stroke frequency were used to calculate technical skill indices, specifically stroke index, and arm propelling efficiency. Relationships between variables were assessed using linear mixed models, identifying fixed, and random effect estimates. Results: Curvilinear trends best described significant longitudinal relationships between maturity status with horizontal velocity (F = 10.33 [1, 233.77]; P = .002) and stroke index (F = 5.55 [1, 217.9]; P = .02) during 200-m Front-crawl trials. Maturity status was not significantly related to arm propelling efficiency (P = .08). However, arm propelling efficiency was an independent predictor of Front-crawl velocity (F = 55.89 [1, 210.45]; P < .001). Conclusions: Maturity status predicted assessment of swimmer technical skill (stroke index) and swimming performance. However, technical skill accessed via arm propelling efficiency was independent of maturation and was predictive of performance. Maturity status influences performance evaluation based on technical skill and velocity. Findings highlight the need to account for maturation and technical skill in age-group swimmers to better inform swimmer evaluation.
Peter A. Hastie
This paper presents a summary of the research on teacher (and preservice teacher) content knowledge within physical education teaching and teacher education. It is organized around the key terms that are predominant in the literature of this field, namely, content knowledge, common content knowledge, and specialized content knowledge. Each of the studies and their key findings are presented within tables. The result is a document that serves as a primer, allowing readers a good understanding of the vocabulary of the field, as well as knowledge of the topics that have been researched to date.
Jaime Fernandez-Fernandez, Alejandro Lopez-Valenciano, Jose Vicente Garcia-Tormo, David Cabello-Manrique, and Juan García-López
Purpose: To analyze the influence of playing 2 consecutive prolonged badminton matches on the shoulder strength and range of motion (ROM) of young players. Methods: Sixteen elite junior badminton players (12 males and 4 females; mean (SD): age 16.2 [0.8] years, body mass 63.5 [6.6] kg, height 173.2 [6.3] cm) participated in a cross-sectional study. Shoulder internal (IR)/external rotation (ER) ROM and IR/ER strength measures were conducted before and after 2 consecutive prolonged (ie, 35 min) matches and 12 hours after the second match. Results: After consecutive matches, IR strength of the dominant side and ER strength of the dominant and nondominant sides (effect size [ES] = 0.20–0.57) were reduced. Shoulder total ROM of the dominant side was decreased (ES = 0.80), while on the nondominant side, IR (ES = 0.66) was also decreased. After 12 hours, results showed decreased values in the IR/ER strength of the dominant side (ES = 0.36–1.00), as well as ER of both dominant and nondominant sides (ES = 0.30–0.59). IR ROM of the nondominant side (ES = 0.69) was also decreased. Conclusion: Present results showed that 2 consecutive matches on the same day with brief rest periods led to significant impairments in shoulder strength and ROM levels. These data can potentially elucidate the need for shoulder-specific training and recovery strategies prior to or during competitions.
Martin K. Erikstad, Bjørn Tore Johansen, Marius Johnsen, Tommy Haugen, and Jean Côté
The personal assets framework suggests that dynamic elements of (a) personal engagement in activities, (b) quality social dynamics, and (c) appropriate settings will influence an athlete’s long-term outcomes of performance, personal development, and continued participation in sport. The aim of the present study was to conduct a case study of a Norwegian age-restricted team that was successful in promoting participation, performance, and positive development for individual participants and to investigate how the dynamic elements of activities, social dynamics, and settings have led to these long-term outcomes. The results indicated that the case is a best-practice example of successful attainment of personal development and long-term participation and performance through appropriate structure and application of the dynamic elements within the personal assets framework, including enjoyable peer-led play activities and quality practice, quality relationships with teammates and coaches, and access to facilities.
Daniel Crago, John B. Arnold, and Christopher Bishop
Purpose: To determine the effect of manipulating foot longitudinal arch motion with different-stiffness foot orthoses on running economy (RE) in runners with flat-arched feet and if changes in arch deformation and recoil were associated with changes in RE. Methods: Twenty-three recreational distance runners performed 5-minute submaximal treadmill runs at 12 km·h−1, in the following 3 conditions in a randomized order: (1) footwear only, (2) flexible orthoses (reduced arch thickness), and (3) standard orthoses. The RE (submaximal steady-state oxygen consumption [VO2submax]) and sagittal arch range of motion were compared among conditions using a repeated-measures analysis of variance and effect sizes (Cohen d). Pearson correlation coefficients were used to determine the association between the change in the sagittal arch range of motion and VO2submax. Results: Compared with standard orthoses, the mean VO2submax was significantly lower in both the flexible orthoses (−0.8 mL·kg−1·min−1, P < .001, d = 0.35) and footwear-only conditions (−1.2 mL·kg−1·min−1, P < .001, d = 0.49). The change in VO2submax between the flexible orthoses and footwear-only conditions was significantly positively correlated with the change in sagittal arch range of motion (r = .591, P = .005). Conclusion: Conventional foot orthoses were associated with poorer RE compared with flexible orthoses and footwear alone. Changes in arch deformation were positively correlated to changes in oxygen consumption, indicating that foot orthoses that limit arch deformation and recoil degrade RE. Foot orthoses that facilitate energy storage and release in the foot longitudinal arch may be advisable for athletes prescribed these devices for clinical purposes to maintain optimal running performance.