Sleep/wake behaviour of competitive adolescent athletes in New Zealand: insight into the impact of early morning training.

OBJECTIVE: Sleep plays a crucial role in the health, wellbeing, and development of adolescent athletes' sporting and academic lives. This study aimed to monitor the sleep/wake behaviour of adolescent athletes who have frequent early morning training sessions. METHODS: 13 swimmers (mean age 14.8 ± 1.4; 46% male) and 19 rowers (mean age 16.5 ± 1.1; all male) wore actigraphs and completed sleep diaries over a 2-week training period. Diaries included the Hooper Index and a question regarding device use before bed. Participants also completed chronotype questionnaires. Nights of the week were categorised as taking place before "morning training", "mornings off", "weekend mornings off", and "weekend morning training". Actigraphy and sleep diary variables were compared for different nights of the week. RESULTS: All athletes were classified as "morning type". Average sleep duration across the study was 7h55 (±1h33). Median sleep duration was significantly shorter on nights before weekday morning training (6h44) compared to weekday mornings off (8h45). This was due to an earlier wake time (04:51) while bedtime remained constant (∼22:15). Athletes went to bed later, woke later and slept for longer on nights before weekend mornings off compared to weekday nights. CONCLUSIONS: Early morning training advanced the wake times of the athletes while bedtime remained constant. This shortened sleep below age recommended durations on the nights before early morning training during the week. These findings suggest that weekly average sleep duration does not accurately reflect athletes' nightly sleep given the large variability across a training week.

Effect of expertise on pacing strategies and sprint performance in batsmen.

OBJECTIVES: To assess whether the absence of a known endpoint, at the beginning of repeated-sprint bouts between the wickets, affects how skilled compared to less skilled batsmen pace themselves. DESIGN: Repeated measures. METHODS: Twelve skilled and 12 less skilled batsmen completed three trials. All trials required the same number of sprints (14 shuttles, 28 runs), while only the information before each trial differed. CT: batsmen were aware of the endpoint (28 runs). UT: not informed of the exercise endpoint and were required to run on command for an indefinite period (28 runs). DT: told they were only doing 14 runs when they actually did 28 runs. Sprint times, electrical muscle activity, and ratings of perceived effort were recorded. RESULTS: Skilled batsmen were significantly faster than less skilled across all trials. Hamstring muscles activity decreased significantly over time in the skilled players during the UT, and during the CT and DT for the less skilled players. There were significant reductions in quadriceps muscles activation for the less skilled over time in all trials and in the skilled batsmen in the vastus medialis during the UT only. Perceived effort increased significantly in both groups in all trials. Skilled batsmen were fastest in the UT and less skilled fastest in the CT. CONCLUSIONS: Better batting skill facilitated improved sprint times, especially when the exact endpoint was unknown. These results suggest that less skilled players should be given more central wicket practice with uncertainty to better develop their ability to maintain their sprint performance.