Association between Low Energy Availability (LEA) and Impaired Sleep Quality in Young Rugby Players.

Low energy availability (LEA) has been associated with several physiological consequences, but its impact on sleep has not been sufficiently investigated, especially in the context of young athletes. This study examined the potential association between energy availability (EA) status and objective sleep quality in 42 male rugby players (mean age: 16.2 ± 0.8 years) during a 7-day follow-up with fixed sleep schedules in the midst of an intensive training phase. Participants' energy intake was weighed and recorded. Exercise expenditure was estimated using accelerometry. Portable polysomnography devices captured sleep on the last night of the follow-up. Mean EA was 29.3 ± 9.14 kcal·kg FFM-1·day-1, with 47.6% of athletes presenting LEA, 35.7% Reduced Energy Availability (REA), and 16.7% Optimal Energy Availability (OEA). Lower sleep efficiency (SE) and N3 stage proportion, along with higher wake after sleep onset (WASO), were found in participants with LEA compared to those with OEA (p = 0.04, p = 0.03 and p = 0.005, respectively, with large effect sizes). Segmented regression models of the EA-sleep outcomes (SE, sleep onset latency [SOL]), WASO and N3) relationships displayed two separate linear regions and produced a best fit with a breakpoint between 21-33 kcal·kg FFM-1·day-1. Below these thresholds, sleep quality declines considerably. It is imperative for athletic administrators, nutritionists, and coaches to conscientiously consider the potential impact of LEA on young athletes' sleep, especially during periods of heavy training.

Influence of Growth, Maturation, and Sex on Maximal Power, Force, and Velocity During Overground Sprinting.

ABSTRACT: Sudlow, A, Galantine, P, Del Sordo, G, Raymond, J-J, Dalleau, G, Peyrot, N, and Duché, P. Influence of growth, maturation, and sex on maximal power, force, and velocity during overground sprinting. J Strength Cond Res 38(3): 491-500, 2024-In pediatric populations maximal anaerobic power, force, and velocity capabilities are influenced by changes in body dimensions and muscle function. The aim of this study was to investigate the influences of growth, maturation, and sex on short-term anaerobic performance. One hundred forty children pre-, mid-, and postpeak height velocity performed two 30-m sprints concurrently measured using a radar device. Maximal power (Pmax), force (F0), and velocity (v0) were calculated from sprint velocity-time data and normalized using sex-specific, multiplicative, allometric models containing body mass, fat-free mass (FFM), or height, and chronological age. Absolute values for Pmax, F0, and v0 were higher with increasing maturity (p < 0.01; d ≥ 0.96), and boys had greater outputs than girls (p < 0.01; d ≥ 1.19). When Pmax and v0 were scaled all maturity-related and sex-related differences were removed. When F0 was scaled using models excluding age, all maturity-related differences were removed except for the least mature group (p < 0.05; d ≥ 0.88) and boys maintained higher values than girls (p < 0.05; d ≥ 0.92). All maturity-related and sex-related differences were removed when F0 was scaled using models including age. Maturity-related and sex-related variance in Pmax and v0 can be entirely explained when FFM, height, and chronological age are accounted for. Regarding F0, there seems to be a threshold after which the inclusion of age is no longer necessary to account for maturity-related differences. In young prepubertal children, the inclusion of age likely accounts for deficits in neuromuscular capacities and motor skills, which body dimensions cannot account for. Practitioners should focus on eliciting neural adaptations and enhancing motor coordination in prepubertal children to improve anaerobic performance during overground sprinting.

Pathways of sleep disturbances in juvenile idiopathic arthritis and recommendations for clinical management approaches: A critical review.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease affecting young people. It has a profound impact on their physical, mental and social lives, leading to long-term disability. With the growing awareness of the importance of sleep in all areas of functioning in young people, an emerging literature has drawn attention to the role of sleep in the pathogenesis of JIA. Sleep disturbances in children and adolescents with JIA arise from a wide range of symptoms and pathways, leading to a vicious cycle that exacerbates subclinical inflammation, symptoms and disease progression. Putative factors contributing to sleep disturbances include chronic inflammation, JIA-associated sleep disorders, JIA symptoms (e.g. pain), psychological comorbidities and potential circadian disruption, which may be exacerbated by the transition to adolescence. Here, we review these pathways and advocate key strategies and alternatives for sleep management in young people with JIA in clinical settings. We identify gaps in knowledge and suggest future directions to improve our understanding of JIA sleep disorders, including clinical trials investigating potential strategies to improve sleep health in this young population.

Energy and Macronutrient Intakes in Young Athletes: A Systematic Review and Meta-analysis.

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.

Fitness and metabolic response to exercise in young adult survivors of childhood lymphoma.

PURPOSE: Childhood lymphoma survivors (CLSs) are at high risk of reduced daily activity. This work studied metabolic substrate use and cardiorespiratory function in response to exercise in CLSs. METHODS: Twenty CLSs and 20 healthy adult controls matched for sex, age, and BMI took an incremental submaximal exercise test to determine fat/carbohydrate oxidation rates. Resting echocardiography and pulmonary functional tests were performed. Physical activity level, and blood metabolic and hormonal levels were measured. RESULTS: CLSs reported more physical activity than controls (6317 ± 3815 vs. 4268 ± 4354 MET-minutes/week, p = 0.013), had higher resting heart rate (83 ± 14 vs. 71 ± 13 bpm, p = 0.006), and showed altered global longitudinal strain (- 17.5 ± 2.1 vs. - 19.8 ± 1.6%, p = 0.003). We observed no difference in maximal fat oxidation between the groups, but it was reached at lower relative exercise intensities in CLSs (Fatmax 17.4 ± 6.0 vs. 20.1 ± 4.1 mL/kg, p = 0.021). At V̇O2 peak, CLSs developed lower relative exercise power (3.2 ± 0.9 vs. 4.0 ± 0.7 W/kg, p = 0.012). CONCLUSION: CLSs reported higher levels of physical activity but they attained maximal fat oxidation at lower relative oxygen uptake and applied lower relative power at V̇O2 peak. CLSs may thus have lower muscular efficiency, causing greater fatigability in response to exercise, possibly related to chemotherapy exposure during adolescence and childhood. Long-term follow-up is essential and regular physical activity needs to be sustained.

Is it wiser to train in the afternoon or the early evening to sleep better? The role of chronotype in young adolescent athletes.

STUDY OBJECTIVES: To examine the effect of the timing of high-intensity exercise (afternoon vs. evening) on adolescent athletes' bedtime psychological state, sleep quality, sleep staging, and next-day wellness/sleepiness according to chronotype. METHODS: Forty-two young athletes (morning type: n = 12, intermediate type: n = 14; evening type: n = 16) completed a randomized crossover study under free-living conditions. The counterbalanced sessions include: (AEX) afternoon (1:00-3:00 p.m.) and (EEX) evening (5:30-7:30 p.m.) high-intensity exercise. Sessions were conducted over three days each and were separated by a 1-week washout period. The time in bed was fixed (10:30 p.m.-7:30 a.m.). Sleep was assessed through ambulatory polysomnography. RESULTS: The effect of high-intensity exercise on sleep differs significantly depending on the time of exercise with lower sleep efficiency: SE (-1.50%, p < .01), and higher SOL (+4.60 min, p ≤=< .01), during EEX vs. AEX. Contrary to the previous view, we discovered differences in the mediated response based on the chronotype of young athletes. These differences were observable in the psychological state at bedtime, objective sleep, and the next day's self-reported wellness. Whereas the sleep of participants with a late chronotype remains stable regardless of the time of exercise, those with an early chronotype experience higher mood disturbances and clinically significant sleep disruptions following evening high-intensity exercise. CONCLUSIONS: Exercise timing and chronotype affect the psychological state at bedtime and objective sleep in adolescent athletes. This also alters next morning signs of pre-fatigue and wellness which suggest that the consideration of both features is important to adolescent athletes' recovery.

The Effects of Different Modalities of an Acute Energy Deficit on Sleep and Next Morning Appetitive and Compensatory Behavior in Healthy Young Adults: The EDIES Protocol.

Sleep is bi-directionally linked to energy balance. This crossover study design will evaluate the acute effect of a moderate energy deficit (500 kcal) induced by diet, exercise, or mixed (-250 kcal by diet and 250 kcal by exercise) on sleep and the next morning's appetitive responses. The study sample comprises 24 healthy young adults. The experimental measurements will be conducted in a naturalistic, momentary manner and partly assessed by the participants. The participants will undergo a run-in period in order to stabilize their sleep schedules and provide them with training on the study protocol and measurements. Indirect calorimetry will be used to determine their resting metabolic rate and peak oxygen consumption (VO2 peak). Then, they will take part in a control session (CTL), followed by three energy deficit sessions in random order: a diet-induced energy deficit session (DED), an exercise-induced energy deficit session (EED), and a mixed energy deficit session (MED). All experimental sessions will be separated by a one-week washout. The participants' sleep will be monitored by ambulatory polysomnography, and the next morning's appetitive response will be evaluated via ad libitum food intake, appetite sensations, and food reward, measured by a food liking and wanting computerized test.

Physical activity as a promising alternative for young people with juvenile idiopathic arthritis: Towards an evidence-based prescription.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in young people. Although biologics now enable most children and adolescents with JIA to enjoy clinical remission, patients present lower physical activity and spend more time in sedentary behavior than their healthy counterparts. This impairment probably results from a physical deconditioning spiral initiated by joint pain, sustained by apprehension on the part of both the child and the child's parents, and entrenched by lowered physical capacities. This in turn may exacerbate disease activity and lead to unfavorable health outcomes including increased risks of metabolic and mental comorbidities. Over the past few decades, there has been growing interest in the health benefits of increased overall physical activity as well as exercise interventions in young people with JIA. However, we are still far from evidence-based physical activity and / or exercise prescription for this population. In this review, we give an overview of the available data supporting physical activity and / or exercise as a behavioral, non-pharmacological alternative to attenuate inflammation while also improving metabolism, disease symptoms, poor sleep, synchronization of circadian rhythms, mental health, and quality of life in JIA. Finally, we discuss clinical implications, identify gaps in knowledge, and outline a future research agenda.

Which Factors Influence Running Gait in Children and Adolescents? A Narrative Review.

In recent years, running has dramatically increased in children and adolescents, creating a need for a better understanding of running gait in this population; however, research on this topic is still limited. During childhood and adolescence multiple factors exist that likely influence and shape a child's running mechanics and contribute to the high variability in running patterns. The aim of this narrative review was to gather together and assess the current evidence on the different factors that influence running gait throughout youth development. Factors were classified as organismic, environmental, or task-related. Age, body mass and composition, and leg length were the most researched factors, and all evidence was in favour of an impact on running gait. Sex, training, and footwear were also extensively researched; however, whereas the findings concerning footwear were all in support of an impact on running gait, those concerning sex and training were inconsistent. The remaining factors were moderately researched with the exception of strength, perceived exertion, and running history for which evidence was particularly limited. Nevertheless, all were in support of an impact on running gait. Running gait is multifactorial and many of the factors discussed are likely interdependent. Caution should therefore be taken when interpreting the effects of different factors in isolation.

Force-velocity profile in sprinting: sex effect.

The ability to produce muscle power during sprint acceleration is a major determinant of physical performance. The comparison of the force-velocity (F-v: theoretical maximal force, F0; velocity, v0 and maximal power output, Pmax) profile between men and women has attracted little attention. Most studies of sex differences have failed to apply a scaling ratio when reporting data. The present study investigated the sex effect on the F-v profile using an allometric model applied with body mass (BM), fat-free mass (FFM), fat-free mass of the lower limb (FFMLL), cross-sectional area (CSA) and leg length (LL) to mechanical parameters. Thirty students (15 men, 15 women) participated. Raw velocity-time data for three maximal 35 m sprints were measured with a radar. Mechanical parameters of the F-v relationship were calculated from the modelling of the velocity-time curve. When F0 and Pmax were allometrically scaled with BM (p = 0.538; ES = 0.23) and FFM (p = 0.176; ES = 0.51), there were no significant differences between men and women. However, when the allometric model was applied to Pmax with FFMLL (p = 0.015; ES = 0.52), F0 with CSA (p = 0.016; ES = 0.93) and v0 with LL (p ≤ 0.001; ES = 1.98) differences between men and women persisted. FFM explained 83% of the sex differences in the F-v profile (p ≤ 0.001). After applying an allometric model, sex differences in the F-v profile are explained by other factors than body dimensions (i.e., physiological qualitative differences).

A Delayed Evening Meal Enhances Sleep Quality in Young Rugby Players.

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.

Isocaloric Diets with Different Protein-Carbohydrate Ratios: The Effect on Sleep, Melatonin Secretion and Subsequent Nutritional Response in Healthy Young Men.

This study aimed to determine the short-term effect of two isocaloric diets differing in the ratio of protein−carbohydrate on melatonin levels, sleep, and subsequent dietary intake and physical activity in healthy young men. Twenty-four healthy men took part in a crossover design including two sessions of three days on isocaloric diets whether high-protein, low-carbohydrate (HPLC) or low-protein, high-carbohydrate (LPHC) followed by 24-h free living assessments. Sleep was measured by ambulatory polysomnography pre-post-intervention. Melatonin levels were assessed on the third night of each session on eight-point salivary sampling. Physical activity was monitored by accelerometry. On day 4, participants reported their 24-h ad-libitum dietary intake. LPHC resulted in better sleep quality and increased secretion of melatonin compared to HPLC. A significant difference was noted in sleep efficiency (p < 0.05) between the two sessions. This was mainly explained by a difference in sleep onset latency (p < 0.01) which was decreased during LPHC (PRE: 15.8 ± 7.8 min, POST: 11.4 ± 4.5 min, p < 0.001). Differences were also noted in sleep staging including time spent on REM (p < 0.05) and N1 (p < 0.05). More importantly, REM latency (PRE: 97.2 ± 19.9 min, POST 112.0 ± 20.7 min, p < 0.001) and cortical arousals (PRE: 7.2 ± 3.9 event/h, POST 8.5 ± 3.3 event/h) increased in response to HPLC diet but not LPHC. On day 4, 24-h ad-libitum energy intake was higher following HPLC compared to LPHC (+64 kcal, p < 0.05) and explained by increased snacking behavior (p < 0.01) especially from carbohydrates (p < 0.05). Increased carbohydrates intake was associated with increased cortical arousals.

Differences in time to task failure and fatigability between children and young adults: A systematic review and meta-analysis.

The transition from childhood to adulthood is characterized by many physiological processes impacting exercise performance. Performance fatigability and time to task failure are commonly used to capture exercise performance. This review aimed to determine the differences in fatigability and TTF between youth (including both children and adolescents) and young adults, and to evaluate the influence of exercise modalities (i.e., exercise duration and type of exercise) on these differences. Medline, SPORTDiscus and Cochrane Library were searched. Thirty-four studies were included. The meta-analyses revealed that both children (SMD -1.15; p < 0.001) and adolescents (SMD -1.26; p = 0.022) were less fatigable than adults. Additional analysis revealed that children were less fatigable during dynamic exercises (SMD -1.58; p < 0.001) with no differences during isometric ones (SMD -0.46; p = 0.22). Children (SMD 0.89; p = 0.018) but not adolescents (SMD 0.75; p = 0.090) had longer TTF than adults. Additional analyses revealed 1) that children had longer TTF for isometric (SMD 1.25; p < 0.001) but not dynamic exercises (SMD -0.27; p = 0.83), and 2) that TTF differences between children and adults were larger for short- (SMD 1.46; p = 0.028) than long-duration exercises (SMD 0.20; p = 0.64). Children have higher endurance and are less fatigable than adults. These differences are influenced by the exercise modality, suggesting distinct physiological functioning during exercise between children and adults. The low number of studies comparing these outcomes between adolescents versus children and adults prevents robust conclusions and warrants further investigations in adolescent individuals.

Sleep pattern and staging in elite adolescent rugby players during the in-season competitive phase compared to an age matched non-athlete population.

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.HIGHLIGHTSAdolescent rugby players have insufficient sleep during both week and weekend of the in-season competitive phaseCongested schedule prevented elite adolescent rugby players from catching up on their sleep at weekends.Sleep considerations are necessary when planning the weekend sporting schedules.

Sleep in children and adolescents with juvenile idiopathic arthritis: a systematic review and meta-analysis of case-control studies.

STUDY OBJECTIVES: Juvenile idiopathic arthritis (JIA) is one of the most common pediatric rheumatic disease. However, sleep alteration associated with this autoimmune disease remain unclear. We aimed in this systematic review and meta-analysis to compare sleep duration, quality, and architecture in JIA subjects with those in their healthy peers. METHODS: Systematic search performed in PubMed, EMBase, Cochrane, and PsycINFO databases included 19 studies in the qualitative synthesis of which 10 met the inclusion criteria for the meta-analysis. RESULTS: Pooled results from subjective methods indicated pronounced sleep disturbances and complaints in youth with JIA compared with their healthy counterparts. This was further confirmed by increased difficulty maintaining sleep (wake after sleep onset [WASO]; standardized mean differences [SMD]: -0.69; CI: -1.29 to -0.09, p = .02) and a tendency to increased difficulty initiating sleep (sleep onset latency [SOL]; SMD: -0.29; CI: -0.60 to 0.03, p = .07). There were no remarkable differences in sleep duration or sleep architecture between JIA patients and healthy controls. High heterogeneity was found for several outcomes. This could be explained by the different methods used as well as associated sleep disorders, medication, and comorbidities. CONCLUSIONS: Although included studies were methodologically diverse, the summarized results of our review and meta-analysis bring evidence that children with JIA present more fragmented sleep compared to healthy peers. Thereby, the implementation of strategies to manage and improve sleep in this population are needed and might have a beneficial effect on the symptoms and functions of JIA. STATEMENT OF SIGNIFICANCE: We observed that youth with Juvenile idiopathic arthritis (JIA) present pronounced sleep disturbances compared to their healthy counterparts: Meta-analysis found more difficulty maintaining sleep and a tendency to increased sleep latency in youth with JIA. However, results show discrepancies due to the different materials and methods used. Larger sample and further disentanglement of sample composition, considering associated sleep disorders, medication and comorbidities should be addressed in future studies.

Eucaloric Balanced Diet Improved Objective Sleep in Adolescents with Obesity.

BACKGROUND: A better understanding of the influence of energy balance on sleep in adolescents, particularly those with obesity, could help develop strategies to optimize sleep in these populations. The purpose of this study was to investigate sleep under ad libitum-vs-controlled diets adjusted to energy requirement (eucaloric) among adolescents with obesity and their normal weight controls. METHODS: Twenty-eight male adolescents aged between 12 and 15 years, n = 14 adolescents with obesity (OB: BMI ≥ 90th centile) and n = 14 normal weight age matched controls (NW), completed an experimental protocol comprising ad libitum or eucaloric meals for three days, in random order. During the third night of each condition, they underwent in home polysomnography (PSG). RESULTS: An interaction effect of energy intake (EI) was detected (p < 0.001). EI was higher during ad libitum compared to the eucaloric condition (p < 0.001) and in OB compared to NW (p < 0.001) in the absence of any substantial modification to macronutrient proportions. Analyses of energy intake distribution throughout the day showed a significant interaction with both a condition and group effect during lunch and dinner. Sleep improvements were noted in OB group during the eucaloric condition compared to ad libitum with reduced sleep onset latency and N1 stage. Sleep improvements were correlated to reduced EI, especially during the evening meal. CONCLUSION: Simply adjusting dietary intake to energy requirement and reducing the energy proportion of the evening meal could have therapeutic effects on sleep in adolescents with obesity. However, positive energy balance alone cannot justify worsened sleep among adolescents with obesity compared to normal weight counterparts.

A Comparison of an Alternative Weight-Grading Model Against Chronological Age Group Model for the Grouping of Schoolboy Male Rugby Players.

OBJECTIVES: Concerns regarding marked differences in the weights and body composition of young rugby players competing within the same age groups have led to the suggestion of alternative models for grouping young players. The aims of this study were (1) to compare variance in the body size and body composition of schoolboy rugby players (9 to 14 years), across weight- and age-grading models, and (2) to identify morphotypes for the weight model using Hattori's body composition chart. MATERIALS AND METHODS: Skinfold thickness measurements were used to assess body fat mass (BF), fat-free mass (FFM), body fat mass index (BFMI), and fat-free mass index (FFMI). Standardized measure of height and weight were taken for all participants. Data were grouped according to the age categories of the French Rugby Federation (U11: Under 11 years, U13: Under 13 years, and U15: Under 15 years), and to the weight categories (W30-44.9; W45-59.9; and W60-79.9) carried out from 25th and 75th weight percentile in each age category. Body mass index status (NW normal-weight versus OW/OB overweight/obese) was considered. Extreme morphotypes are characterized from BFMI and FFMI in the weight-grading model on Hattori's body composition chart. RESULTS: The dispersion of anthropometric characteristics decreased significantly for the weight model, except for height in all groups and BFMI for U13. Among NW, 3, 1.8, and 0% upgraded; 18.2, 68.7, and 45.5% downgraded; among OW, 50, 21.5, and 12.5%; and among OB, 91.3, 83.3, and 74.6% upgraded, respectively, in U11, U13, U15. FFMI/BFMI were correlated in U11 (r = 0.80, p < 0.001), U13 (r = 0.66, p < 0.001), and U15 (r = 0.77, p < 0.001). There was no significant correlation in W45-59.9 and low correlations in W30-44.9 (r = 0.25, p < 0.001) and W60-79.9 (r = 0.29, p < 0.001). Significant grading difference between the centroids (p < 0.05) and the distribution deviates from centroids of BFMI and FFMI (p < 0.0001) were noted between the two models. Thirteen players were located in adipo-slender, twenty-three in adipo-solid, twenty-two in lean-slender, and two located in the lean-solid morphotype in weight model. CONCLUSION: A weight-grading model should be considered to limit mismatches in anthropometric variables. However, variations of body composition also persisted for this model. Hattori's body composition chart allowed more detailed examination of morphological atypicalities among schoolboy rugby players.

Effect of morning versus evening exercise training on sleep, physical activity, fitness, fatigue and quality of life in overweight and obese adults.

This study compares the effectiveness of a 12-week moderate exercise training program (METP), performed in the morning versus the evening, on sleep, physical activity, physical fitness, sleepiness, fatigue and health-related quality of life (HRQoL) in overweight and obese patients. Sedentary and inactive overweight/obese adults (n = 36) were included in METP and randomized into two groups: morning group (GM) and evening group (GE). Twenty-eight participants successfully completed METP (3 × 90 min exercise session per week for 12 weeks, completion rates >80%). Sleep, physical activity, and bedtime temperature were measured using accelerometry and infrared tympanic temperature during 3 separate weeks of the study (Week1, Week6, and Week12). Participants also took part in baseline and endpoint assessments including physical fitness as well as subjective physical activity, chronotype, sleep quality, sleepiness, fatigue and HRQoL. METP did not impact objective sleep quality differently between the two groups (morning vs evening). Bedtime and mid-sleep were advanced when METP was done in the morning whereas they were delayed when METP was practiced in the early evening (p = .003). Beside this finding, no valuable differences between the two groups were noted in all the remaining measures. METP resulted in improvements of body composition, cardiorespiratory and muscular endurance, as well as a favorable impact on subjective sleep quality, diurnal sleepiness, fatigue and HRQoL in both groups (all p < .05). Evening METP could be an effective alternative for overweight/obese adults when morning METP is not possible.

Maximal Fat Oxidation During Exercise Is Already Impaired in Pre-pubescent Children With Type 1 Diabetes Mellitus.

Objective: We evaluated substrate utilization during submaximal exercise, together with glycemic responses and hormonal counter-regulation to exercise, in children with type 1 diabetes mellitus (T1DM). Methods: Twelve pre-pubescent children with T1DM and 12 healthy children were matched by sex and age. Participants completed a submaximal incremental exercise test to determine their fat and carbohydrate oxidation rates by indirect calorimetry. Levels of glycemia, glucagon, cortisol, growth hormone, noradrenaline, adrenaline, and insulin were monitored until 120 min post-exercise. Results: Absolute peak oxygen uptake (VO2 peak) was significantly lower in the children with T1DM than in the healthy controls (1131.4 ± 102.5 vs. 1383.0 ± 316.6 ml.min-1, p = 0.03). Overall carbohydrate and lipid oxidation rates were the same in the two groups, but for exercise intensities, higher than 50% of VO2 peak, fat oxidation rate was significantly lower in the children with T1DM. The absolute maximal lipid oxidation rate was significantly lower in the T1DM children (158.1 ± 31.6 vs. 205.4 ± 42.1 mg.min-1, p = 0.005), and they reached a significantly lower exercise power than the healthy controls (26.4 ± 1.2 vs. 35.4 ± 3.3 W, p = 0.03). Blood glucose responses to exercise were negatively correlated with pre-exercise blood glucose concentrations (r = -0.67; p = 0.03). Conclusion: Metabolic and hormonal responses during sub-maximal exercise are impaired in young children with T1DM.