Search

The aim of this study was to examine the effect of delayed evening mealtime on sleep quality in young athletes. Twelve rugby players (age 15.8 ± 0.7 years) participated in a crossover within-participant design. Adolescents spent five consecutive days in each of two conditions, separated by a 2-week washout period: routine dinner (3.5 hr before bedtime) and late dinner (LD, 1.5 hr before bedtime). Other mealtimes as well as bedtime and wake-up time were usual and remained the same in both conditions. Their schedules, dietary intakes, and physical activity were controlled and kept constant throughout the study. Sleep was assessed using polysomnography on the first and the last nights in the individual rooms of the boarding school. An increase in total sleep time by 24 min (p =.001, d = 1.24) and sleep efficiency by 4.8% was obtained during LD (p =.001, d = 1.24). Improvement in sleep efficiency was mainly due to a lower wake after sleep onset (−25 min, p =.014, d = −3.20), a decrease of microarousals (−25%, p =.049, d = −0.64), and awakenings ≥90 s (−30%, p <.01, d = −0.97) in LD compared to routine dinner. There were no significant differences in sleep architecture except for a shorter slow-wave sleep (N3) latency (−6.9 min, p =.03, d = −0.778) obtained during LD. In this study, evening dinner 1.5 hr before bedtime leads to better quality and less fragmented sleep compared to evening dinner 3.5 hr before bedtime in young athletes. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of maturity status on force-velocity relationships in a ballistic lower limb (BLL) test in high-level soccer adolescents and young adults. The population was 61 adolescents (13.0–17.9 years) and 23 young adults (18.0–26.2 years). Subjects completed the BLL test on a ballistic ergometer equipped with two force plates and a linear encoder. Following Samozino's method, maximal power output (Pmax), force (F0) and velocity (v0) were determined. An allometric model was applied to Pmax and F0 with body mass (BM) and fat-free mass (FFM). Significant effects of maturity status were found for absolute Pmax, F0, relative Pmax to BM and FFM, relative F0 to FFM and F0 allometrically scaled to BM and FFM (p = 0.02 to p < 0.001; $\eta $ η = 0.10 to $\eta $ η = 0.49). There was no significant effect for Pmax allometrically scaled to BM and FFM, F0 relative to BM and v0. Body dimensions explain group differences in Pmax whereas for F0, qualitative factors explain the differences between the groups. As maturity status and body dimensions influence Pmax, these factors should be considered when assessing explosive short efforts. This could help to better identify potential athletic talent and adapt training content. [ABSTRACT FROM AUTHOR]

The aim of this study was to conduct a systematic review and meta-analysis of differences in energy and macronutrient intakes between young athletes and non-athletes, considering age, gender and sport characteristics. The study included original research articles that compared energy and macronutrient intakes of 8 to 18-year-old athletes to non-athletes. Mean difference (MD) meta-analyses were performed to quantify energy and macronutrient intake differences between athletes and non-athletes. Eighteen observational studies were included. Results revealed that the energy and carbohydrate consumption of athletes was higher than that of non-athletes (MD=4.65kcal/kg/d, p<0.01 and MD=1.65% of total energy intake, p<0.01, respectively). Subgroup analyses revealed a significant effect of total training time on the observed mean differences between athletes and non-athletes. As practice time increased, the differences between athletes and non-athletes increased for carbohydrate and decreased for protein. Sport type analysis revealed a higher protein intake by mixed sport athletes compared to endurance and power sports. Analyses also indicated an age effect: the older the athletes, the smaller the differences between athletes and non-athletes for energy intake. However, the methods used to match groups and estimate dietary intakes forced us to moderate the results. More rigorous research methods are needed to define the dietary intakes of athletes and non-athletes. [ABSTRACT FROM AUTHOR]

Objective. In a context of inflammatory disease such as juvenile idiopathic arthritis (JIA), we do not know what impact physical activity may have on a deregulated immune system. The objective is to measure the impact of a single bout of exercise on plasma inflammatory markers such as calprotectin, IL-6, sIL-6R, sgp130, and the hypothalamic-pituitary-adrenal axis in children with juvenile idiopathic arthritis. Methods. Twelve children with JIA performed a nonexercise control day and a consecutive day that included a 20 min exercise bout at 70% of max-HR at 08:30 am. Venous blood samples were taken at 08:30, 08:50, 09:30, 10:30 am, and 12:00 pm to measure plasma concentrations of calprotectin, IL-6, sIL-6R, sgp130, cortisol, and ACTH. Pain was evaluated at 08:30, 08:50 am, and 06:00 pm. Results. There was a transient twofold increase in postexercise self-evaluated pain (p=0.03) that disappeared in the evening. A single bout of exercise resulted in a 1.7-fold increase in plasma calprotectin (p

Purpose: To examine the effect of drop height on vertical jumping performance in children with respect to sex and maturity status. Methods: Thirty-seven pre-pubertal, 71 circa-pubertal, and 69 post-pubertal boys and girls performed, in a randomized order, 2 squat jumps, 2 countermovement jumps, and 2 drop jumps (DJ) from heights of 20, 30, 40, 50, 60, and 70 cm. The trial with the best jump height in each test was used for analysis. Results: No significant sex × maturity status × jump type interaction for jump height was observed. However, on average, the children jumped higher in the countermovement jump than in squat jump and DJs (+1.2 and +1.6 cm, P <.001, respectively), with no significant differences between DJs and squat jumps or between DJs when increasing drop heights. Regarding DJs, 59.3% of the participants jumped higher from drop heights of 20 to 40 cm. Conclusions: Children, independent of sex and maturity status, performed best in the countermovement jump, and no performance gain was obtained by dropping from heights of 20 to 70 cm. During maturation, the use of drop heights between 20 and 40 cm may be considered in plyometric training, but the optimum height must be obtained individually. [ABSTRACT FROM AUTHOR]

Despite the importance of sleep monitoring in the context of sport, few studies to date examined night-to-night sleep variability among adolescent athletes. This study compared night-to-night sleep variation between junior rugby players and age-matched non-athlete adolescents across seven consecutive nights of the in-season competitive phase. This investigation is based on data from a single centre, observational prospective study including 30 adolescents (15 junior rugby players and 15 non-athlete age-matched controls). Sleep was continuously monitored using ambulatory electroencephalogram (EEG) recordings. While the non-athlete controls catch-up on their sleep debt during the weekend by delaying their wake-up time, junior rugby players opt for an earlier bedtime to cope with sport-related travel (Fri: −00:57 h:min; p < 0.001; Sat: −01:58 h:min; p < 0.001) or early school (Mon: −00:55 h:min; p < 0.001). Night-to-night sleep examination identified greater sleep disturbances in junior rugby players the nights before and after the competition SE (Fri: −11%; p < 0.001; Sat: −9 min; p < 0.01). Junior rugby players showed higher IIV in sleep duration (CVTST: + 5.8%; P < 0.001), efficiency (CVSE: + 3.8%; p < 0.001) and staging (CVN2: + 5.4%; p < 0.001; CVN3: + 4.5; p < 0.01 IIV; REM: + 16.4%; p < 0.01). Higher IIV in the young athletes' sleep outcomes could make them even more vulnerable to health and wellness concerns (i.e. overtraining, injury). The study results show the urgent need for an appropriate consideration of sleep regularity in young athletes. [ABSTRACT FROM AUTHOR]

Young athletes must contend with the constraints of elite sports on top of school commitments and the physiological processes associated with adolescence. This study assessed week and weekend sleep and schedule of activities in elite adolescent rugby players during the in-season competitive phase compared with age-matched non-athlete controls. 32 adolescents (GR: 16 elite rugby players, GC: 16 controls) from the same boarding school filled out a daily schedule of activities and a sleep diary, and wore a multichannel electroencephalogram for 14 days. They later filled out questionnaires on their sleep quality, sleepiness, and perceived stress. Both groups showed insufficient sleep duration during the week (<7 h). Only GC caught up on their sleep debt during the weekend (increased TIB, TST and time spent in REM sleep, all p < 0.001). Weekend TIB, TST and, N3 sleep remained similar to that for weekdays in GR. However, GR experienced lower sleep quality (decreased SE, increased WASO, all p < 0.01) and a decrease in REM sleep (p < 0.01). Schedules of activities showed an increase in time spent on overall activities during the weekend, mainly due to competition and sport-specific travel, which resulted in a decrease in sleep opportunity time compared with GC (p < 0.001). Δ sleep opportunity time (weekend-week) was associated with Δ TST (weekend-week), and Δ TST (weekend-week) was associated with sleepiness and perceived stress. Busy schedules during the competitive season decreased sleep opportunity time and prevented elite adolescent rugby players from catching up on their sleep at weekends. HIGHLIGHTS Adolescent rugby players have insufficient sleep during both week and weekend of the in-season competitive phase Congested schedule prevented elite adolescent rugby players from catching up on their sleep at weekends. Sleep considerations are necessary when planning the weekend sporting schedules [ABSTRACT FROM AUTHOR]