The Effect of Age, Biological Maturation and Birth Quartile in the Kinanthropometric and Physical Fitness Differences between Male and Female Adolescent Volleyball Players

Background: Differences in kinanthropometric and physical fitness performance between boys and girls usually start during adolescence, as a result of the changes in the hormonal environment that occur with the advance of age and biological maturation; Methods: A total of 96 1st Regional Division players adolescent volleyball players, 48 males, (age = 14.17 ± 1.00 years-old) and 48 females (age = 14.41 ± 1.21 years-old) underwent a kinanthropometric assessment, were asked to perform different physical fitness test and to complete a questionnaire. Chronological age, maturity offset, age at peak height velocity (APHV), and birth quartile were calculated; Results: Statistical differences were observed between male and female players in the APHV (p < 0.001). Male players showed higher values in the bone and muscle-related variables (p < 0.001–0.040), as well as in the strength and power production-related physical tests (p < 0.001–0.012), while the female showed higher values in the fat-related variables (p = 0.003–0.013), and performed better in the flexibility tests. Age, maturity offset, and birth quartile showed to have statistical influence in the differences found between sex groups; Conclusions: There is a clear influence of age and biological maturation on the differences found between sexes in adolescent volleyball players that could be taken into account regarding grouping in early stages.

Predictive Analytic Techniques to Identify Hidden Relationships between Training Load, Fatigue and Muscle Strains in Young Soccer Players

This study aimed to analyze different predictive analytic techniques to forecast the risk of muscle strain injuries (MSI) in youth soccer based on training load data. Twenty-two young soccer players (age: 13.5 ± 0.3 years) were recruited, and an injury surveillance system was applied to record all MSI during the season. Anthropometric data, predicted age at peak height velocity, and skeletal age were collected. The session-RPE method was daily employed to quantify internal training/match load, and monotony, strain, and cumulative load over the weeks were calculated. A countermovement jump (CMJ) test was submitted before and after each training/match to quantify players’ neuromuscular fatigue. All these data were used to predict the risk of MSI through different data mining models: Logistic Regression (LR), Random Forest (RF), Support Vector Machine (SVM). Among them, SVM showed the best predictive ability (area under the curve = 0.84 ± 0.05). Then, Decision tree (DT) algorithm was employed to understand the interactions identified by the SVM model. The rules extracted by DT revealed how the risk of injury could change according to players’ maturity status, neuromuscular fatigue, anthropometric factors, higher workloads, and low recovery status. This approach allowed to identify MSI and the underlying risk factors.

Association Between Paternal Separation During Early Childhood and Pubertal Timing Among Girls Using Longitudinal Birth Cohort in Japan

IntroductionPrevious studies have shown that paternal absence leads to earlier pubertal timing among girls in high-income countries. Despite the low divorce rate in Japan, paternal separation is commonly seen due to a unique corporation system, tanshin funin, where employees relocate with their spouses and children. We examined paternal separation, including paternal absence (due to divorce or paternal death) and paternal tanshin funin, during early childhood as a predictor of earlier girl’s pubertal development, assessed as age at peak height velocity (PHV).MethodsThis study examined 15 214 girls from a longitudinal survey conducted in Japan from 2001 to 2016 by the Ministry of Health, Labor and Welfare. Paternal separation was determined by the occurrence through annual surveys conducted at ages 0.5 to 4.5 years. Outcome was defined as age at PHV between ages 6 to 15 years. We conducted linear regression, adjusted for potential confounders and other covariates.ResultsContinuous father cohabitation was seen in 88.7% of households, while paternal separation was experienced 1-2, 3-4 and 5 times (always) among 7.4%, 2.8% and 1.1% of households, respectively. Girls who confronted continuous paternal separation (5 times) experienced 0.42 years earlier [95% confidence interval (CI): -0.75, -0.10] age at PHV compared to their peers who always lived with their fathers.ConclusionGirls who experienced paternal separation throughout ages 0.5 to 4.5 years experienced PHV earlier.

Does Predicted Age At Peak Height Velocity Explain Physical Performance In U13-15 Basketball Female Players?

Background: The aims of the study were (i) to identify the physical fitness and basic anthropometric characteristics of Polish female basketball players aged 13 to 15 years, (ii) to show the effect of maturity timing on the performance in motor tests and basic body composition parameters, (iii) to identify the index that contributes most to the prediction of performance in the tests of speed, jumping ability, agility, and endurance. Methods: The sample included 925 female Polish players (U13-15). In part 1, maturity timing category distribution were examined within across age-groups. In part 2, the relationship between the anthropometric variables, physical fitness performance was assessed based on maturity timing categories (ANCOVA analysis). In part 3, backward stepwise multiple regression analyse quantified the relationship between maturity timing (group of PHV) and physical performance.Results: ANCOVA results (age, body height, and body mass as covariates) showed in the U13 female basketball players significantly higher sprinting (20m), jumping ability and endurance tests results of the PHV1 group.Better results was observed in U14 female players in PHV1 compared to PHV2 and PHV3 in 20m and jumping tests but opposite trend was observed for 5m sprint and endurance test (distance covered and VO2max). U15 basketball players from the PHV3 group were characterized by better results of jumping abilities, endurance, 10m and 20m sprint and agility (total, S4) tests. Maturity timing (10m), chronological age (5 m, 20 m, agility, SVJ, VJ, and VO2max tests), body height (10m), body mass (10m, 20m, VJ, VO2max), and the interaction between body mass and height (SVJ) were significant (adjusted R2 = 0.02-0.10; p < 0.001) predictors of motor skills. Conclusion: The results can help the coaches to personalize training programs and to adapt the training content to the biological age of the players.

Determining the timing of pubertal onset via a multicohort analysis of growth

Objective Growth-based determination of pubertal onset timing would be cheap and practical. We aimed to determine this timing based on pubertal growth markers. Secondary aims were to estimate the differences in growth between cohorts and identify the role of overweight in onset timing. Design This multicohort study includes data from three Finnish cohorts—the Type 1 Diabetes Prediction and Prevention (DIPP, N = 2,825) Study, the Special Turku Coronary Risk Factor Intervention Project (STRIP, N = 711), and the Boy cohort (N = 66). Children were monitored for growth and Tanner staging (except in DIPP). Methods The growth data were analyzed using a Super-Imposition by Translation And Rotation growth curve model, and pubertal onset analyses were run using a time-to-pubertal onset model. Results The time-to-pubertal onset model used age at peak height velocity (aPHV), peak height velocity (PHV), and overweight status as covariates, with interaction between aPHV and overweight status for girls, and succeeded in determining the onset timing. Cross-validation showed a good agreement (71.0% for girls, 77.0% for boys) between the observed and predicted onset timings. Children in STRIP were taller overall (girls: 1.7 [95% CI: 0.9, 2.5] cm, boys: 1.0 [0.3, 2.2] cm) and had higher PHV values (girls: 0.13 [0.02, 0.25] cm/year, boys: 0.35 [0.21, 0.49] cm/year) than those in DIPP. Boys in the Boy cohort were taller (2.3 [0.3, 4.2] cm) compared with DIPP. Overweight girls showed pubertal onset at 1.0 [0.7, 1.4] year earlier compared with other girls. In boys, there was no such difference. Conclusions The novel modeling approach provides an opportunity to evaluate the Tanner breast/genital stage–based pubertal onset timing in cohort studies including longitudinal data on growth but lacking pubertal follow-up.

Kinetics and kinematics of sprinting in mid and post peak height velocity female athletes

Sprinting speed is a crucial physical capacity and can change throughout an athlete’s growth. Previous research has shown that both kinetic and kinematic variables change across maturation in young males. However, due to the changes in growth and hormonal levels, the kinetic and kinematic factors associated with sprinting may vary in young females compared to their male counterparts. Therefore, determining kinetics (force, maximal power) and kinematics (step length, step frequency, contact time and flight time) associated with sprinting in young females can provide valuable insights into training for this cohort. Thirty-two young female athletes, 11 mid-peak height velocity (PHV) age (12.8±0.6) and 21 post PHV (13.5±0.93) performed two 15 and 30 m sprints each. Theoretical velocity, maximal velocity, step length, force and power max were significantly higher in post PHV girls (p<0.05). Univariate regression analysis reported that the best predictors of velocity (15 and 30 m) were contact time, power max, stride frequency, step length and leg length with contact time being the strongest predictor. The findings of this research provide insight into the natural development of sprinting in young females and will help practitioners specifically develop training programs that can effectively improve sprinting kinetics and kinematics in this cohort.

Hubungan Status Gizi dan Aktivitas Fisik dengan Kejadian Hipertensi Remaja

Adolescence is peak height velocity that affect changes in body composition, rapidgrowth on weight, bone mass, pysical activity and nutritional status. Overweight and lack ofphysical activity are risk factors of hyertension in adolescents. Overweight adolescents havea 4,85 times risk of developig hypertension compared to adolescents with normal nutritionalstatus. Lack of physical activity has 7,86 times the risk of developing hypertension thanadolescents with active physical activity. Hypertension in adolescents increase risk ofmorbidity and mortality in adults. This study aim to determine the correlation between nutritional status and physicalactivity with hypertension in adolescents. A quantitative research with cross sectional designwas developed. Respondents in this study were 75 college students. Data analysis usingSpearman’s Correlation test. Proportion of obesity and overweight was 20%. Physical activity of the respondentsbelongs to light category. The incidence of hypertension I 14,67% and hypertension II2,67%. Results shows that there was correlation between nutritional status and physicalactivity with hypertension in adolescents.Keywords : nutritional status, physical activity, hypertension, adolescents

The Study of Maturational Timing Effect in Elite Portuguese Adolescent Basketball Players: Anthropometric, Functional and Game Performance Implications

To estimate age at peak height velocity (APHV) in Portuguese male adolescents and; test the effect of maturational status in physical fitness attributes and individual game performance of U-14 basketball players. One mixed-longitudinal cohort with a sample of 439 Portuguese male adolescents and; one cross sectional sample of 172 Portuguese elite U-14 basketball players. The on-time group was defined within a 1-year band (more or less) from mean APHV. Preece-Baines model 1 was adopted to fit the mean stature curve. Independent samples t-tests and Kruskal-Wallis tests were performed and effect size (partial eta square) was calculated. The growth fitting revealed an APHV around 13.45 years for Portuguese male adolescents. Early maturing players exceeded significantly their peers in body size and composition, jump power and upper body strength. Early and on-time maturing players scored better in rebounds won per game (APHV = 13.81, 13.30 years), Performance Index Rating (PIR) and points scored per minute. Maturation influences morphology attributes and strength regardless of the APHV (13.81, 13.45, 13.30 years) used to obtain the cut-off points. It is recommended to use the new Portuguese mean APHV value to avoid extreme classifying bias groups.