Sixteen men completed four trials at random as follows: (Trial A) performance of a single bout of resistance exercise preceded by placebo ingestion (vitamin C); (Trial B) ingestion of 1,500 mg L-arginine and 1,500 mg L-lysine, immediately followed by exercise as in Trial A; (Trial C) ingestion of amino acids as in Trial B and no exercise; (Trial D) placebo ingestion and no exercise. Growth hormone (GH) concentrations were higher at 30,60, and 90 min during the exercise trials (A and B) compared with the resting trials (C and D) (p < .05). No differences were noted in [GH] between the exercise trials. [GH] was significantly elevated during resting conditions 60 min after amino acid ingestion compared with the placebo trial. It was concluded that ingestion of 1,500 mg arginine and 1,500 mg ly sine immediately before resistance exercise does not alter exercise-induced changes in [GH] in young men. However, when the same amino acid mixture is ingested under basal conditions, the acute secretion of GH is increased.
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Richard R. Suminski, Robert J. Robertson, Fredric L. Goss, Silva Arslanian, Jie Kang, Sergio DaSilva, Alan C. Utter and Kenneth F. Metz
Ben D. Kern, Kim C. Graber, Amelia Mays Woods and Tom Templin
Physical education teachers have been criticized for not implementing progressive or innovative instruction resulting in enhanced student knowledge and skills for lifetime participation in physical activity. Purpose: To investigate how teachers with varying dispositions toward change perceive socializing agents and teaching context as barriers to or facilitators of making pedagogical change. Methods: Thirty-two teachers completed a survey of personal dispositions toward change and participated in in-depth interviews. Results: Teachers perceived that students’ response to instructional methods and student contact time (days/week), as well as interactions with teaching colleagues and administrators influenced their ability to make pedagogical changes. Teachers with limited student contact time reported scheduling as a barrier to change, whereas daily student contact was a facilitator. Change-disposed teachers were more likely to promote student learning and assume leadership roles. Conclusion: Reform efforts should include consideration of teacher dispositions and student contact time.
João Ribeiro, Luís Teixeira, Rui Lemos, Anderson S. Teixeira, Vitor Moreira, Pedro Silva and Fábio Y. Nakamura
Purpose : The current study aimed to compare the effects of plyometric (PT) versus optimum power load (OPL) training on physical performance of young high-level soccer players. Methods : Athletes were randomly divided into PT (horizontal and vertical drills) and OPL (squat + hip thrust exercises at the load of maximum power output) interventions, applied over 7 weeks during the in-season period. Squat and countermovement jumps, maximal sprint (10 and 30 m), and change of direction (COD; agility t test) were the pretraining and posttraining measured performance variables. Magnitude-based inference was used for within- and between-group comparisons. Results : OPL training induced moderate improvements in vertical squat jump (effect size [ES]: 0.97; 90% confidence interval [CI], 0.32–1.61) and countermovement jump (ES: 1.02; 90% CI, 0.46–1.57), 30-m sprint speed (ES: 1.02; 90% CI, 0.09–1.95), and COD performance (ES: 0.93; 90% CI, 0.50–1.36). After PT training method, vertical squat jump (ES: 1.08; 90% CI, 0.66–1.51) and countermovement jump (ES: 0.62; 90% CI, 0.18–1.06) were moderately increased, while small enhancements were noticed for 30-m sprint speed (ES: 0.21; 90% CI, −0.02 to 0.45) and COD performance (ES: 0.53; 90% CI, 0.24–0.81). The 10-m sprint speed possibly increased after PT intervention (small ES: 0.25; 90% CI, −0.05 to 0.54), but no substantial change (small ES: 0.36; 90% CI, −0.40 to 1.13) was noticed in OPL. For between-group analyses, the COD ability and 30-m sprint performances were possibly (small ES: 0.30; 90% CI, −0.20 to 0.81; Δ = +1.88%) and likely (moderate ES: 0.81; 90% CI, −0.16 to 1.78; Δ = +2.38%) more improved in the OPL than in the PT intervention, respectively. Conclusions : The 2 different training programs improved physical performance outcomes during the in-season period. However, the combination of vertically and horizontally based training exercises (squat + hip thrust) at optimum power zone led to superior gains in COD and 30-m linear sprint performances.
Ben T. Stephenson, Sven P. Hoekstra, Keith Tolfrey and Victoria L. Goosey-Tolfrey
Purpose: Paratriathletes may display impairments in autonomic (sudomotor and/or vasomotor function) or behavioral (drinking and/or pacing of effort) thermoregulation. As such, this study aimed to describe the thermoregulatory profile of athletes competing in the heat. Methods: Core temperature (T c) was recorded at 30-second intervals in 28 mixed-impairment paratriathletes during competition in a hot environment (air temperature = 33°C, relative humidity = 35%–41%, and water temperature = 25°C–27°C), via an ingestible temperature sensor (BodyCap e-Celsius). Furthermore, in a subset of 9 athletes, skin temperature was measured. Athletes’ wetsuit use was noted while heat illness symptoms were self-reported postrace. Results: In total, 22 athletes displayed a T c ≥ 39.5°C with 8 athletes ≥40.0°C. There were increases across the average T c for swim, bike, and run sections (P ≤ .016). There was no change in skin temperature during the race (P ≥ .086). Visually impaired athletes displayed a significantly greater T c during the run section than athletes in a wheelchair (P ≤ .021). Athletes wearing a wetsuit (57% athletes) had a greater T c when swimming (P ≤ .032), whereas those reporting heat illness symptoms (57% athletes) displayed a greater T c at various time points (P ≤ .046). Conclusions: Paratriathletes face significant thermal strain during competition in the heat, as evidenced by high T c, relative to previous research in able-bodied athletes and a high incidence of self-reported heat illness symptomatology. Differences in the T c profile exist depending on athletes’ race category and wetsuit use.
Guillaume P. Ducrocq, Thomas J. Hureau, Olivier Meste and Grégory M. Blain
Context: Drop jumps and high-intensity interval running are relevant training methods to improve explosiveness and endurance performance, respectively. Combined training effects might, however, be achieved by performing interval drop jumping. Purpose: To determine the acute effects of interval drop jumping on oxygen uptake (
Siobhán O’Connor, Róisín Leahy, Enda Whyte, Paul O’Donovan and Lauren Fortington
Camogie is one of Ireland’s most popular sports, and the full contact nature presents a high potential for injury. This study aims to present the first overview of elite and nonelite camogie injuries by examining adult players’ self-reported worst injuries from one season. At least one injury was sustained by 88.2% of camogie players during the previous season and 60.0% sustained 2+ injuries. Knee and ankle ligaments, hamstring strains and hand/fingers/thumb fractures were key injuries identified, which can lead to substantive health and economic impacts. Further research to establish the mechanism of these injuries is required in order to start shaping potential measures for their prevention.
Lubna Abdul Razak, Tara Clinton-McHarg, Jannah Jones, Sze Lin Yoong, Alice Grady, Meghan Finch, Kirsty Seward, Edouard Tursan d’Espaignet, Rimante Ronto, Ben Elton and Luke Wolfenden
Background: Identifying factors influencing the implementation of evidence-based environmental recommendations to promote physical activity in childcare services is required to develop effective implementation strategies. This systematic review aimed to: (1) identify barriers and facilitators reported by center-based childcare services impacting the implementation of environmental recommendations to increase physical activity among children, (2) synthesize these factors according to the 14 domains of the “Theoretical Domains Framework,” and (3) report any associations between service or provider characteristics and the reported implementation of such recommendations. Methods: Electronic searches were conducted in 6 scientific databases (eg, MEDLINE) and Google Scholar to identify studies reporting data from childcare staff or other stakeholders responsible for childcare operations. Included studies were based on childcare settings and published in English. From 2164 identified citations, 19 articles met the inclusion criteria (11 qualitative, 4 quantitative, and 4 mixed methods). Results: Across all articles, the majority of factors impacting implementation fell into the “environmental context and resources” domain (eg, time, equipment, and space; n = 19) and the “social influences” domain (eg, support from parents, colleagues, supervisors; n = 11). Conclusion: The current review provides guidance to improve the implementation of environmental recommendations in childcare services by addressing environmental, resource, and social barriers.
Blake D. McLean, Kevin White, Christopher J. Gore and Justin Kemp
Purpose: There is debate as to which environmental intervention produces the most benefit for team sport athletes, particularly comparing heat and altitude. This quasi-experimental study aimed to compare blood volume (BV) responses with heat and altitude training camps in Australian footballers. Methods: The BV of 7 professional Australian footballers (91.8 [10.5] kg, 191.8 [10.1] cm) was measured throughout 3 consecutive spring/summer preseasons. During each preseason, players participated in altitude (year 1 and year 2) and heat (year 3) environmental training camps. Year 1 and year 2 altitude camps were in November/December in the United States, whereas the year 3 heat camp was in February/March in Australia after a full exposure to summer heat. BV, red cell volume, and plasma volume (PV) were measured at least 3 times during each preseason. Results: Red cell volume increased substantially following altitude in both year 1 (d = 0.67) and year 2 (d = 1.03), before returning to baseline 4 weeks postaltitude. Immediately following altitude, concurrent decreases in PV were observed during year 1 (d = −0.40) and year 2 (d = −0.98). With spring/summer training in year 3, BV and PV were substantially higher in January than temporally matched postaltitude measurements during year 1 (BV: d = −0.93, PV: d = −1.07) and year 2 (BV: d = −1.99, PV: d = −2.25), with year 3 total BV, red cell volume, and PV not changing further despite the 6-day heat intervention. Conclusions: We found greater BV after training throughout spring/summer conditions, compared with interrupting spring/summer exposure to train at altitude in the cold, with no additional benefits observed from a heat camp following spring/summer training.
Marissa L. Mason, Marissa N. Clemons, Kaylyn B. LaBarre, Nicole R. Szymczak and Nicole J. Chimera
Clinical Scenario: Lower-extremity injuries in the United States costs millions of dollars each year. Athletes should be screened for neuromuscular deficits and trained to correct them. The tuck jump assessment (TJA) is a plyometric tool that can be used with athletes. Clinical Question: Does the TJA demonstrate both interrater and intrarater reliability in healthy individuals? Summary of Key Findings: Four of the 5 articles included in this critically appraised topic showed good to excellent reliability; however, caution should be taken in interpreting these results. Although composite scores of the TJA were found to be reliable, individual flaws do not demonstrate reliability on their own, with the exception of knee valgus at landing. Aspects of the TJA itself, including rater training, scoring system, playback speed, volume, and number of views allotted, need to be standardized before the reliability of this clinical assessment can be further researched. Clinical Bottom Line: The TJA has shown varying levels of reliability, from poor to excellent, for both interrater and intrarater reliability, given current research. Strength of Recommendation: According to the Centre for Evidence Based Medicine levels of evidence, there is level 2b evidence for research into the reliability of the TJA. This evidence has been demonstrated in elite, adolescent, and college-level athletics in the United Kingdom, Spain, and the United States. The recommendation of level 2b was chosen because these studies utilized cohort design for interrater and intrarater reliability across populations. An overall grade of B was recommended because there were consistent level 2 studies.