Alannah K.A. McKay, Peter Peeling, David B. Pyne, Nicolin Tee, Marijke Welveart, Ida A. Heikura, Avish P. Sharma, Jamie Whitfield, Megan L. Ross, Rachel P.L. van Swelm, Coby M. Laarakkers, and Louise M. Burke
This study implemented a 2-week high carbohydrate (CHO) diet intended to maximize CHO oxidation rates and examined the iron-regulatory response to a 26-km race walking effort. Twenty international-level, male race walkers were assigned to either a novel high CHO diet (MAX = 10 g/kg body mass CHO daily) inclusive of gut-training strategies, or a moderate CHO control diet (CON = 6 g/kg body mass CHO daily) for a 2-week training period. The athletes completed a 26-km race walking test protocol before and after the dietary intervention. Venous blood samples were collected pre-, post-, and 3 hr postexercise and measured for serum ferritin, interleukin-6, and hepcidin-25 concentrations. Similar decreases in serum ferritin (17–23%) occurred postintervention in MAX and CON. At the baseline, CON had a greater postexercise increase in interleukin-6 levels after 26 km of walking (20.1-fold, 95% CI [9.2, 35.7]) compared with MAX (10.2-fold, 95% CI [3.7, 18.7]). A similar finding was evident for hepcidin levels 3 hr postexercise (CON = 10.8-fold, 95% CI [4.8, 21.2]; MAX = 8.8-fold, 95% CI [3.9, 16.4]). Postintervention, there were no substantial differences in the interleukin-6 response (CON = 13.6-fold, 95% CI [9.2, 20.5]; MAX = 11.2-fold, 95% CI [6.5, 21.3]) or hepcidin levels (CON = 7.1-fold, 95% CI [2.1, 15.4]; MAX = 6.3-fold, 95% CI [1.8, 14.6]) between the dietary groups. Higher resting serum ferritin (p = .004) and hotter trial ambient temperatures (p = .014) were associated with greater hepcidin levels 3 hr postexercise. Very high CHO diets employed by endurance athletes to increase CHO oxidation have little impact on iron regulation in elite athletes. It appears that variations in serum ferritin concentration and ambient temperature, rather than dietary CHO, are associated with increased hepcidin concentrations 3 hr postexercise.
Johnpaul Caia, Shona L. Halson, Patrick M. Holmberg, and Vincent G. Kelly
Purpose: To examine the sleep of rugby league athletes the night before and following an evening match and to investigate the association between caffeine intake and sleep on the night of competition. Methods: On the night prior to, night of, and night after a professional rugby league match, 15 athletes had their sleep monitored using wrist activity monitors. Additionally, saliva samples were collected 60 minutes before and 30 minutes after the competition to assess salivary caffeine concentration. Differences in sleep across the 3 nights were examined using linear mixed models, and changes were assessed using effect size (ES). Pearson correlation (r) assessed the relationship between salivary caffeine levels and sleep indices. Results: On the night of competition, athletes went to bed later than the night before (P = .00002, ES = 1.84) and night after (P = .0003, ES = 1.49) competition. Consequently, their sleep duration was reduced on the night of competition compared with the previous night (P < .0000003, ES = 2.36) and night after competition (P = .001, ES = 1.53). Postcompetition salivary caffeine concentration was substantially elevated in athletes when compared with precompetition measures (P < .00000001, ES = 4.44), and moderate, nonsignificant correlations were observed between changes in salivary caffeine concentration and delayed bedtime (r = .48, P = .07), increased sleep latency (r = .45, P = .09), decreased sleep duration (r = −.30, P = .28), and reduced sleep efficiency (r = −.34, P = .22). Conclusions: These results demonstrate that evening competition results in sleep disturbance in rugby league athletes, and caffeine supplementation prior to and during competition leads to substantial increases in postcompetition salivary caffeine concentration.
Adson Alves da Silva, Gabriel Lucas Morais Freire, José Fernando Vila Nova de Moraes, Leonardo de Souza Fortes, Rodrigo Gustavo da Silva Carvalho, and José Roberto Andrade do Nascimento Junior
This study investigated the association of coping strategies burnout symptoms in 228 Under-20 Brazilian soccer players in a career transition phase and compared these variables with the occurrence of injuries and professionalization. The instruments used in the study were the Athlete Burnout Questionnaire and the Athletic Coping Strategies Inventory-28. Data analysis was conducted through generalized estimation equations, Pearson correlation, and multiple linear regression (p < .05). The results showed that coping was associated with physical and emotional exhaustion in both professional and nonprofessional players, and with a reduced sense of accomplishment only in young nonprofessional athletes who were in the career transition phase. It is concluded that young elite athletes who are in the transition phase of their career but have not signed a professional contract, use limited coping strategies and seem more exposed to stress (compared with those who have signed a contract), and are consequently more vulnerable to burnout symptoms.
Alannah K.A. McKay, Rachel McCormick, Nicolin Tee, and Peter Peeling
This study determined the impact of heat stress on postexercise inflammation and hepcidin levels. Twelve moderately trained males completed three, 60-min treadmill running sessions under different conditions: (a) COOL, 18 °C with speed maintained at 80% maximum heart rate; (b) HOTHR, 35 °C with speed maintained at 80% maximum heart rate; and (c) HOTPACE, 35 °C completed at the average running speed from the COOL trial. Venous blood samples were collected pre-, post-, and 3-hr postexercise and analyzed for serum ferritin, interleukin-6 (IL-6), and hepcidin concentrations. Average HR was highest during HOTPACE compared with HOTHR and COOL (p < .001). Running speed was slowest in HOTHR compared with COOL and HOTPACE (p < .001). The postexercise increase in IL-6 was greatest during HOTPACE (295%; p = .003). No differences in the IL-6 response immediately postexercise between COOL (115%) and HOTHR (116%) were evident (p = .992). No differences in hepcidin concentrations between the three trials were evident at 3 hr postexercise (p = .407). Findings from this study suggest the IL-6 response to exercise is greatest in hot compared with cool conditions when the absolute running speed was matched. No differences in IL-6 between hot and cool conditions were evident when HR was matched, suggesting the increased physiological strain induced from training at higher intensities in hot environments, rather than the heat per se, is likely responsible for this elevated response. Environmental temperature had no impact on hepcidin levels, indicating that exercising in hot conditions is unlikely to further impact transient alterations in iron regulation, beyond that expected in temperate conditions.
Anqi Deng, Tan Zhang, Yubing Wang, and Ang Chen
Purpose: Informed by the constructivist learning theory, the purpose of this study was to determine the impact of three continuing professional development (CPD) approaches on student learning in a healthful living physical education curriculum. Methods: Physical education teachers (n = 19) received one of the following CPD trainings: (a) Full Training, (b) Expedited Training, or (c) Self-Training. The effect of each CPD method was determined by tracking student learning (N = 3,418) with a two-level linear mixed model. Results: The results showed that Full Training CPD was able to generate the largest knowledge gain in both the Healthy Lifestyles Unit (β = 0.214, p < .001) and Cardio Fitness Club Unit (β = 0.184, p < .01) in comparison with the other two CPD approaches. Discussion: These findings advance our understanding of the role different CPD approaches play in enhancing student learning in the subjects of cardiorespiratory fitness and health lifestyles. Conclusions: The Full-Training CPD appears to benefit student learning the most followed by the Expedited-Training. The Self-Training would yield the least learning achievement.
Vitor Ciampolini, Martin Camiré, William das Neves Salles, Juarez Vieira do Nascimento, and Michel Milistetd
In the sports coaching field, learner-centered teaching (LCT) has been advocated as a viable approach to increasing learners’ involvement in the learning process. However, implementing LCT is not a simple undertaking as coach developers, and coaches have encountered dilemmas when it comes to shifting to LCT in coach education. This study aimed to investigate how LCT principles were implemented in a rugby coach education program through the perspectives of the researcher, the coach developer, and coaches. Participants included the researcher (i.e., first author), a coach developer, and 10 rugby coaches. The researcher observed three coach education courses, gathered descriptive and reflective field notes, and conducted individual semistructured interviews with both the coach developer and the 10 coaches. Findings shed light on the strategies adopted by the coach developer and the extent to which these strategies aligned with LCT principles. Coaches discussed how they enjoyed their active role in the courses and the approaches used by the coach developer to leverage learning. The discussion highlights the importance of coach developers in facilitating a learning process that is challenging, motivating, and supports coaches throughout the courses.
Keita Kinoshita, Eric MacIntosh, and Shintaro Sato
Basic psychological needs (BPN) are a construct that helps clarify the psychological mechanism to reach desirable outcomes for youth athletes. When BPN are undermined, people should be less likely to thrive. As mental toughness (MT) can reduce the negative effects of stressors, MT may buffer the negative effects of maladaptive motivation. This study investigated the mediating role of thriving on the relationships between BPN thwarting and important outcomes for youth athletes’ positive functioning. It also examined the buffering effects of MT. One hundred eighty-eight Canadian youth athletes (M age = 15.51) answered an online survey. The results demonstrated that thriving was a significant mediator, and the indirect relationships were moderated by MT. The indirect associations were nonsignificant for youth with high MT. The findings demonstrated that MT might decrease the negative impacts of BPN thwarting on thriving and important outcomes for young athletes.