Limb-belt resisted sprint training improves physical fitness and ball-throw velocity in pubertal handball players.

The study assessed the effect of six weeks of biweekly upper and lower limbs' weighted-belt resisted sprint training (BRST) and weighted-vest resisted sprint training (VRST), or normal sprint training (NST) on muscle strength, speed, change of direction and handball-throwing velocity in young handball players. Twenty-seven pubertal male handball players aged 14.4 years were randomly assigned into BRST (n = 9), VRST (n = 8), and NST (n = 8) groups. Sprint ability (10-m and 30-m), squat jump (SJ), countermovement jump (CMJ), free-arm countermovement jump (CMJFA), standing long jump (SLJ), Five-jump test (FJT), change of direction and handball-throw velocity were assessed before and after a 6-week training in-season program. Within-group interactions showed that BRST improved all tests' performances (moderate-to-large). VRST improved sprint, SLJ, FJT and handball-throw velocity performances (small-to-large). NST improved only the change of direction performances (moderate). Between-groups comparison revealed that BRST improved all testing performances, except change of direction, compared with NST (large) and improved 30-m sprint, CMJFA, FJT and handball-throw velocity performance compared with VRST (moderate-to-large). In addition, VRST improved 30-m sprint, SJ and handball-throw velocity performances compared with NST (moderate-to-large). Throwing performance changes correlated with changes in sprint time and horizontal and vertical jump abilities (r = 0.40 to r = 0.69; p < 0.01). We conclude that while both resisted sprint training improved players' sprint, jumping and handball-throw performances, substantial improvements were recorded with the BRST compared to VRST and NST. Thus, BRST could be recommended to male U15 handball players as a valuable training method for developing physical fitness and skill performances.

Effect of maturation level on normative specific-agility performance metrics and their fitness predictors in soccer players aged 11-18 years.

BACKGROUND: In sports sciences, normative data serve as standards for specific physical performance attributes, enhancing talent identification within a specific population. The aim of this study was to provide standard data for Agility-15 m, Ball-15 m tests, and skill index, considering maturation level, specifically age at peak height velocity (PHV). The study also investigated the relationship between relative performances in these tests and anthropometrics, jumping (squat jump [SJ], countermovement jump [CMJ]), and sprinting abilities (S-5 m, S-10 m, S-20 m, S-30 m) in young soccer players. METHODS: The study involved 647 soccer players aged 11-18 years, categorized into three groups: pre-PHV, circum-PHV, and post-PHV. Statistical analysis was conducted using analysis of variance and Bonferroni post hoc testing to detect variations among maturation groups, and Pearson's correlation test to examine the relationship between factors. RESULTS: Agility-15 m and ball-15 m performances among maturity groups showed significant differences (p < 0.01). Significant correlations were identified in pre-PHV group, between lower limb length and Agility-15 m (r=-0.23, p < 0.05) and between height and Ball-15 m (r=-0.23, p < 0.05). In post-PHV group, there was a correlation between body fat percentage (BF %) and Agility-15 m (r = 0.17, p < 0.05) and Ball-15 m (r = 0.21, p < 0.05). In all maturity groups, there were significant correlations between agility and sprint tests (S-5 m, S-10 m, S-20 m, and S-30 m) and muscle power (SJ and CMJ). CONCLUSION: The study revealed that both speed and lower limb power significantly influence agility in young soccer players, providing valuable insights for coaches and practitioners to create tailored training plans and interventions for different age groups and maturity levels.

Allometric Association between Six-Minute Walk Distance and Both Body Size and Shape in Young Obese Girls.

BACKGROUND: The 6-min walk test (6MWT) provides information regarding functional capacity, response to therapy and prognosis in a variety of chronic cardiovascular disorders. Variability in body size and composition, particularly in obese people, confounds the six-minute covered distance (6MWD). The aim of the present study was to adopt allometric models to identify the most appropriate body size/shape; i.e., body mass (BM), body height (BH), body mass index (BMI) and estimated fat-free mass (FFM); associated with the 6MWD in 190 young girls with obesity. METHODS: Nonlinear allometric modeling was used to calculate common body size exponents for BM, BH, BMI and FFM. In a validation sample of 35 age-matched obese girls, these allometric exponents were used prospectively. RESULTS: The point estimates for the size exponents (95% confidence interval) from the separate allometric models were: BM 0.23 (0.19-0.27), BH 0.91 (0.78-1.03), BMI 0.33 (0.23-0.44) and FFM 0.28 (0.24-0.33). The presence of significant residual size correlations for 6MWD/BH-0.91 indicates that the influence of body size was not correctly partitioned out. In the validation group, the correlations between 6MWD BM-b and BM, 6MWD BMI-b and BMI, and 6MWD FFM-b and FFM using the established exponents were not statistically different from zero (r = 0.01), implying that participants in the allometric investigation were not penalized based on their BM, BMI, or FFM. CONCLUSION: We conclude that BM, BMI, BH and FFM, as indicators of body size/shape, are the most valid allometric denominators for the scaling of 6MWD in a group of young girls with obesity.

Fatigue score as a promising complementary training monitoring tool: a pilot study in elite rugby sevens players.

The aim of this study was to compare physical and hormonal responses of seventeen elite rugby sevens players over a 6-week intense training block (IT) and a consecutive 2-week tapering period (TAP), using a fatigue cut-off score of 20 as a potential moderating variable. Training was monitored by daily training load (TL) and strain (TS) (using the session rating of perceived exertion [sRPE]) and also the weekly total score of fatigue (TSF; 8-item questionnaire tool). Testing and 24 h urinary cortisol (CL), cortisone (CN), adrenaline (AD) and noradrenalin (NAD) concentrations were also analysed before (T0) and after IT (T1) and after the TAP (T2). Players were assigned to group 1 with a TSF above 20 (G1 > 20, n = 9) and group 2 with a TSF below 20 (G2 < 20, n = 8) according to the French Society for Sports Medicine guidelines. TSF (effect size [ES] from 1.17 to 1.75), TL (ES from 0.81 to 1.06) and TS (ES from 1.23 to 1.40) were higher in G1 > 20 than in G2 < 20 over IT. Likewise, performance standards (ES from 1.58 to 2.61) and AD levels were lower (ES = 3.20), whereas CL and CL/CN ratio (ES from 1.60 to 3.47) were higher in G1 > 20 than in G2 < 20. After the TAP, TSF, TL and TS returned to baseline values for both groups, with an increase in performance standards and normalization in hormone levels. We suggest that a TSF greater than or equal to 20 could be considered as a fatigue threshold generating hormone disturbance and performance decrement, making it a potentially useful preventive and complementary training monitoring tool.

Six-minute walk distance equation in children and adolescents with obesity.

AIM: To develop a 6-minute walk-distance (6MWD) reference equation for children and adolescents with obesity, and to assess its determinant factors. METHODS: A cross-sectional study using mixed linear and multiple regression models was conducted in 497 children (235 girls and 262 boys) aged 6-18 years with a body mass index (BMI) greater than 97th percentile. Anthropometrics and a 6-minute walk test (6MWT) were performed. RESULTS: Mean 6MWD was 547 ± 86 m for girls and 575 ± 96 m for boys, which averaged ~80% of a reference normal-weight population matched for age and ethnicity. Age, weight and BMI were positively correlated with 6MWD whereas waist and hip circumferences (WC and HC, respectively) were negatively correlated with 6MWD for both genders. The combination of age, height, BMI and HC explained 69% of the 6MWD variability in the equation for the whole population. Moreover, the combination of age, height, HC as well as the combination of age, height, BMI and WC explained 67% and 75% of the variability in the girls' and boys' equations, respectively. CONCLUSION: This 6MWD reference equation, which was influenced by abdominal obesity markers in a gender-specific way, extends and enhances scientific knowledge and provides useful predictive tools for the care of obese children.

Association of Physical and Technical Activities With Partial Match Status in a Soccer Professional Team.

Moalla, W, Fessi, MS, Makni, E, Dellal, A, Filetti, C, Di Salvo, V, and Chamari, K. Association of physical and technical activities with partial match status in a soccer professional team. J Strength Cond Res 32(6): 1708-1714, 2018-The purpose of this study was to examine the association between physical and technical activities and partial match status (winning, drawing, or losing) in a professional soccer team over 2 seasons. Physical and technical activities of 52 official matches were collected and analyzed at each 15-minute interval, for each half (45 minutes), and full match (90 minutes) using a multiple-camera computerized tracking system. The results indicated that according to full match outcome: winning status was characterized by players covering more total distance (p ≤ 0.05) and low-intensity running (<14.4 km·h) (p ≤ 0.05), whereas, losing status induced more sprinting (≥25.2 km·h) (p < 0.01) and high-intensity running (≥19.8 km·h) (p ≤ 0.05). However, according to partial match status (i.e., 15 minutes and half time), players covered more distance for all running intensities while winning (p < 0.01). Technical match performance scores were not influenced by match status. In conclusion, the present study showed that the physical activities including high-intensity running and total distance covered were related to the match status, whereas technical activities were not. The overall outcome shows that higher physical activity was associated with winning partial match periods. This approach highlights the importance of physical fitness in soccer and may help coaches to better modulate players' roles and team tactical organization throughout the match.

Correlation of resistin with inflammatory and cardiometabolic markers in obese adolescents with and without metabolic syndrome.

OBJECTIVE: The link between plasma resistin and obesity-related cardiometabolic disorders in children remains debatable. This study assessed the relationships of plasma resistin with cardiovascular risk factors, pro-inflammatory markers and insulin resistance index (HOMA-IR) in obese (Ob) adolescents and obese adolescents with metabolic syndrome (Ob-MS) compared to healthy controls (CO). METHODS: 114 obese adolescents (60 Ob, age 13.6 ± 0.9 years, BMI 28.0 ± 2.2 kg/m(2), and 54 Ob-MS, age 13.8 ± 1.0 years, BMI 32.5 ± 4.8 kg/m(2)) and 37 CO (age 13.7 ± 0.8 years, BMI 22.8 ± 0.8 kg/m(2)) were studied. Anthropometrics, cardiac variables as well as fasting plasma concentrations of lipids, glucose, insulin, and adipocytokines (resistin, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP)) were measured. HOMA-IR was calculated, and the presence of MS was assessed. RESULTS: Plasma resistin was significantly higher in Ob-MS than in both Ob and CO and was correlated with anthropometric, cardiovascular, pro-inflammatory markers and several components of MS as was HOMA-IR in Ob and Ob-MS. With increasing the number of MS components, plasma resistin, pro-inflammatory markers, and HOMA-IR were also increased. Multiple regression models highlighted significant correlation between resistin and both HOMA-IR (r = 0.40, p < 0.05) and systolic blood pressure (r = 0.63, p < 0.01) in Ob-MS. CONCLUSION: These results support the hypothesis that there is an association between circulating resistin and childhood obesity-related inflammatory and cardiometabolic events.

Monitoring training load and fatigue in rugby sevens players.

PURPOSE: Trainers and physical fitness coaches' need a useful tool to assess training loads to avoid overtraining. However, perceived scales or questionnaires were required. Therefore, the purpose of this study was to assess whether a short 8-item questionnaire of fatigue could be a useful tool for monitoring changes in perceived training load and strain among elite rugby Sevens (7s) players during preparation for a major competition. METHODS: Sixteen elite rugby 7s players completed an 8-week training program composed of 6-week intense training (IT) and 2-week reduced training (RT). They were tested before (T0), after the IT (T1) and after the RT (T2). The quantification of the perceived training load and strain were performed by the session-RPE (rating of perceived exertion) method and concomitantly the 8-item questionnaire of fatigue was administered. RESULTS: Training load (TL) and strain (TS) and total score of fatigue (TSF from the 8-item questionnaire) increased during IT and decreased during RT. Simultaneously, physical performances decreased during IT and were improved after LT. The changes in TL, TS and TSF correlated significantly over the training period (r=0.63-0.83). CONCLUSIONS: These findings suggest that the short questionnaire of fatigue could be a practical and a sensitive tool for monitoring changes in training load and strain in team-sport athletes. Accordingly, the simultaneous use of the short questionnaire of fatigue along with the session-RPE method for perceived changes in training load and strain during training could provide additional information on the athletes' status, allowing coaches to prevent eventual states of overreaching or overtraining.

The Homeostasis Model Assessment-adiponectin (HOMA-AD) is the most sensitive predictor of insulin resistance in obese children.

OBJECTIVES: The aim of this study was to examine the efficacy of three indices i.e. adiponectin/leptin ratio, HOMA-IR and HOMA-AD in assessing insulin resistance among obese children. PATIENTS AND METHODS: One hundred and twenty-two obese children (57 girls, 65 boys): mean age 13.7±1.3 years, BMI 30.1±4.5kg/m(2), eight tanner stage I, 48 tanner stage II-III, 66 tanner stage IV-V, participated in this study. They were classified into four groups according to sex and the presence of metabolic syndrome characteristics: with metabolic syndrome (MS; 21 girls and 36 boys) and controls without metabolic syndrome (CON, 36 girls and 29 boys). The correlations between these three indices of insulin resistance and the MS criteria were analyzed using linear and multiple regressions and receiver operating characteristics (ROC) curves analysis. RESULTS: The majority of anthropometric and biological parameters as well as adiponectin/leptin ratio, HOMA-IR and HOMA-AD were significantly different between MS and CON in both sexes. Both HOMA-AD and HOMA-IR were significantly correlated with the majority of metabolic syndrome components than was the adiponectin/leptin ratio in MS of both sexes. In boys and girls with and without MS, multiple regression analyses highlighted that both HOMA-AD and adiponectin/leptin ratio (r=-0.99 and r=-0.54 for MS girls and boys respectively, 0.05

Six-minute walking test and the assessment of cardiorespiratory responses during weight-loss programmes in obese children.

PURPOSE: We assessed the exercise tolerance and cardiorespiratory responses during 2-month weight-loss programmes using the 6-minute walking test (6MWT) in obese children. METHODS: Twenty-eight male obese children were randomly assigned to either a control group (C), an energy restriction group (R), an exercise training at maximum lipid-oxidation (LIPOXmax) group (E), or an energy restriction/training group (RE). The body composition, the submaximal incremental cycling exercise, and the 6MWT were performed before and after the 2-month programme. RESULTS: . After the programme, RE group showed a significant improvement of body composition (body weight reduced by 6.3 ± 1.5 kg, p < 0.01), and an increase of 6-minute walking distance (6MWD) (+13.7%, p < 0.01). Similarly, maximum oxygen uptake calculated according to the American College of Science Medicine guideline (VO(2max) ACSM) and VO(2max) predicted from 6MWD were respectively higher (+12.9% and +10.0%, p < 0.01) than the R or E groups. Bland-Altman analysis highlighted an agreement of these two methods of VO(2max) measurement. Moreover, in all participants the 6MWD was significantly correlated with VO(2max) ACSM and LIPOXmax (r = 0.77, p < 0.001 and r = 0.67, p < 0.01; respectively) before the programme as well as their changes in percentage over the programme (r = 0.85 and r = 0.86, p < 0.0001; respectively). CONCLUSIONS: We concluded that a 2-month weight-loss programme including energy restriction and exercise training targeted at LIPOXmax improved body composition and cardiorespiratory tolerance in obese children. Furthermore, the 6MWT could be considered as a useful and reliable tool for the assessment and the follow-up of cardiorespiratory responses during weight-loss programme in obese children.

Effect of individualized exercise training combined with diet restriction on inflammatory markers and IGF-1/IGFBP-3 in obese children.

AIMS: The present study was designed to examine the possible changes in body composition, insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein-3 (IGFBP-3) and inflammatory markers of obese children in response to a 2-month program of exercise training combined with dietary restriction. METHODS: Twenty-eight obese children (age 13.2 +/- 0.7 years, body mass index 30.9 +/- 1.3) were randomly assigned to a diet/training group or a control group and were tested two times: once before and once at the end of the experimental period. They performed a progressive cycle ergometer test at each visit. Substrate oxidation was evaluated by indirect calorimetry. Training was individualized at the point when fat oxidation was maximal (Lipox(max)). RESULTS: Diet/training induced a significant decrease in body weight and body fat (after vs. before, p < 0.01). Plasma concentrations of IGF-1, IGFBP-3 and inflammatory markers were significantly decreased after the completion of the program. The diet/training program resulted in an increase in VO(2max)ACSM (24.6 +/- 2.5 to 33.1 +/- 3.1 ml/min/kg, p < 0.001) at the end of the intervention period. CONCLUSION: These data suggest that in the presence of weight loss, exercise training improves inflammatory markers and IGF-1 and IGFBP-3 levels in obese children.

Long-term rugby practice enhances bone mass and metabolism in relation with physical fitness and playing position.

We attempted to clarify whether rugby was able to enhance bone mineral density (BMD) and content (BMC) of weight-bearing bones by modifying bone remodelling in relation to physical fitness in male rugby players compared to controls. 22 male international rugby players aged 20-31 years (forwards, n = 12 and backs, n = 10) were compared to 14 age-matched controls of the same ethnic origin aged 21-33 years. BMD and BMC were measured by DEXA and bone metabolism was evaluated by specific makers. Physical fitness level was analysed in parallel. Both forwards and backs exhibited significantly higher BMD (+15%, +6%, respectively) and BMC (+36%, +18%, respectively) for whole body and all examined sites, regions and segments than controls, with more pronounced difference at forwards. The difference between both groups of rugby players and controls noted for BMD became more pronounced for BMC (+52% for lower limbs). BMD and BMC values were higher in forwards than backs at total body (+9, +16%) and at stressed sites such as spine (+12%, +13%), pelvis (+10%, +11%), upper (+17% for BMC) and lower limbs (+9%, +18%). Athletes, especially forwards, presented higher concentrations of OC and CTX resulting in positive values of the uncoupling index. Total body lean mass as well as muscular strength strongly correlated with total and stressed regional sites such as spine, pelvis, and lower limbs BMD and BMC (r = 0.59, p < 0.01 to r = 0.84, p < 0.001). Similarly, OC, but not CTX, is highly correlated with the same regional and total BMD and BMC (r = 0.67 to r = 0.81, p < 0.001). Rugby participation is associated with improved physical fitness, enhanced axial and appendicular bone mass and increased bone turnover in adult athletes. Moreover, the positive bone adaptation of these athletes may be related to an increase of bone remodelling rate in favour of bone formation, especially in forwards.