Maturation-Related Differences in Adaptations to Resistance Training in Young Male Swimmers

Reference Values of Physical Performance in Handball Players Aged 13-19 Years: Taking into Account Their Biological Maturity

Biological maturity status significantly influences success in handball, impacting an athlete's performance and overall development. This study aimed to examine the anthropometric and physical performance variables concerning age and maturity status, establishing reference values for physical performance among Tunisian players. A total of 560 handball players (309 males and 251 females aged 13-19 years) were categorized based on maturity status: early (n = 98), average (n = 262), and late (n = 200), determined through Mirwald and colleagues' equations. Anthropometric, physical fitness, and physiological data were collected for reference value creation. Our findings revealed significantly higher anthropometric parameters (p = 0.003) in late-maturing athletes compared to their early-maturing counterparts. Post-pubertal athletes showed significantly superior (p = 0.002) jumping ability, change of direction, and aerobic performance compared to their pre-pubertal peers. Additionally, male athletes outperformed females in both fitness (p = 0.001) and aerobic (p = 0.001) performance. A notable age-by-maturity interaction emerged for most performance outcomes (η2 ranging from 0.011 to 0.084), highlighting increased sex-specific differences as athletes progressed in age. Percentile values are provided for males and females, offering valuable insights for coaches and sports scientists to design personalized training programs. Understanding a player's performance relative to these percentiles allows trainers to tailor workouts, addressing specific strengths and weaknesses for enhanced development and competitiveness.

A randomised controlled trial of 1- versus 2-day per week formats of Nordic hamstring training on explosive athletic tasks in prepubertal soccer players

This randomised controlled trial examined the effect of volume-equated programmes of Nordic hamstring exercise (NHE) training, executed at frequencies of 1- or 2-days per week, on explosive athletic tasks (30 m sprint, 15 m manoeuvrability and standing long jump [SLJ]) in male youth soccer players (mean age: 10.3 ± 0.5 years). Players were divided into an experimental group (n = 31) which was further subdivided into 1-day (n = 16) and 2-days (n = 15) per week training conditions, and a control group (n = 14). There were significant group-by-time interactions for 30-m sprint (p < 0.001, d = 0.6), SLJ (p = 0.001, d = 1.27) and 15 m manoeuvrability (p < 0.001, d = 0.61). The experimental group demonstrated small to moderate effect sizes in 30-m sprint (d = 0.42, p = 0.077), SLJ (d = 0.97, p < 0.001) and 15 m manoeuvrability (d = 0.61, p < 0.001). The control group showed small significant performance decrements or no change in these variables. There were no significant differences between the 1-day and 2-day training groups. In two of the three tests (30 m sprint, SLJ) the 2-day group demonstrated larger effect sizes. The NHE enhances explosive athletic task performance in prepubertal youth soccer players and there may be only small advantages to spreading training over two days instead of one.

The Influence of Maturity Status on Dynamic Balance Following 6 Weeks of Eccentric Hamstring Training in Youth Male Handball Players

Information about when to apply an appropriate eccentric hamstring strength training stimulus during long-term athlete development is essential for effective programming and improving balance performance. This study examined the effects of six-week eccentric hamstring training on dynamic balance performance in youth handball players of different maturity statuses (pre- or post-peak height velocity (PHV)). A randomized controlled design with 45 young male handball players (14.6 ± 0.3 years) from a local national handball club were randomly allocated to a 6 week, twice weekly eccentric hamstring training in two experimental groups: a pre-PHV (maturation offset: −2.13 ± 0.63, n = 10) and post-PHV (maturation offset: 0.79 ± 0.34, n = 12) group and two control groups: maturation offset: −2.09 ± 0.61, n = 10 and maturation offset: 0.55 ± 0.67, n = 13. Dynamic balance performance was evaluated by using the composite score during the lower quarter Y-balance test from pre- and post-intervention. A significant effect on balance scores was found from pre to post (F = 11.4; p = 0.002; η2p = 0.22), intervention (F = 5.4; p = 0.025; η2p = 0.12), and maturation (F = 369; p < 0.001; η2p = 0.9), but no significant interaction effects were found (F ≥ 3.3; p ≥ 0.077; η2p ≤ 0.07). Post hoc analysis revealed that the post-PHV group had a higher score than the pre-PHV group. Furthermore, that dynamic balance increased in the post-PHV group after intervention much more in the control post-PHV group. It was concluded that somatic maturation influences dynamic balance performance and that eccentric hamstring training results in greater improvement in balance performance in young male handball players for the post-pubertal group.

Effects of Integrative Neuromuscular Training and Detraining on Countermovement Jump Performance in Youth Volleyball Players

ABSTRACT

Nunes, ACCA, Cattuzzo, MT, Faigenbaum, AD, and Mortatti, AL. Effects of integrative neuromuscular training and detraining on countermovement jump performance in youth volleyball players. J Strength Cond Res 35(8): 2242-2247, 2021-The purpose of this study was to analyze the effect of integrative neuromuscular training (INT) on countermovement vertical jump height (CVJH) performance in youth volleyball players before and after a detraining period. Thirty-two novice volleyball players were cluster randomized into 2 groups: intervention group-INT (age: 13.1 ± 0.4 years; body mass: 55.3 ± 12.1 kg; and height: 161.1 ± 6.4 cm) and control group-CON (age: 12.8 ± 0.7 years; body mass: 51.8 ± 13.6 kg; and height: 160.1 ± 10.7 cm). The subjects were evaluated for somatic maturation (years from peak height velocity) and for CVJH performance at 4 time points during the 20-week study period: baseline, 6 weeks of INT, 12 weeks of INT, and 8 weeks after INT (detraining). The analysis used repeated-measures analysis of variance and Bonferroni post hoc test to identify possible differences in the CVJH delta in both groups. Spearman correlation was performed to verify the association between the values of the vertical jump tests and maturational levels found. The INT showed a significant improvement in the CVJH from baseline to 12 weeks and maintained training-induced gains after detraining period (p > 0.001). Significant increase in CVJH was found in the percentage of change (Δ%) from baseline to 6 weeks (p < 0.005), 12 weeks (p < 0.001), and detraining (p < 0.001) in INT compared with the CON. The results of this study indicate that INT was able to improve CVJH performance in novice youth volleyball players and these gains were sustained during the detraining period. These findings indicate that regular participation in supervised INT can enhance jumping performance in young volleyball players, and that this type of neuromuscular program may be particularly beneficial for youth with limited fundamental motor skill performance.

Biological Age in Relation to Somatic, Physiological, and Swimming Kinematic Indices as Predictors of 100 m Front Crawl Performance in Young Female Swimmers

BACKGROUND

Some swimmers reach high performance level at a relatively young age. The purpose of this study is to determine the relationship between adolescent female swimmers' 100 m front crawl race (Vtotal100) and several anthropometry, body composition, and physiological and specific strength indices.

METHODS

Nineteen adolescent female swimmers were examined for biological age (BA) and body composition. Oxygen uptake was measured during water-flume stage-test front crawl swimming with ventilatory thresholds examination. Specific strength indices were assessed during 30 s of tethered swimming. Stroke rate (SR), stroke length (SL), and stroke index (SI) were also examined.

RESULTS

BA was strongly correlated with anthropometrics and tethered swimming strength indices, and showed moderate to strong correlation with ventilatory thresholds. Speed of swimming in the race was moderately to largely correlated with speed at V˙O2&nbsp;max-VV˙O2max (r = 0.47-0.55; p < 0.05)-ventilatory thresholds (VAT,&nbsp;VRCP) (r = 0.50-0.85; p < 0.05), SL (r = 0.58-0.62; p < 0.05), and SI (r = 0.79-0.81; p < 0.01).

CONCLUSION

Results confirmed a significant role of biological maturation mediation on body composition and body size, ventilatory indices, and specific strength indices. BA was not a significant mediation factor influencing the swimming kinematics (SL, SI) and speeds of VAT, VRCP or VV˙O2&nbsp;max, which were strong predictors of the 100 m race.

Effects of Progressed and Nonprogressed Volume-Based Overload Plyometric Training on Components of Physical Fitness and Body Composition Variables in Youth Male Basketball Players

ABSTRACT

Palma-Muñoz, I, Ramírez-Campillo, R, Azocar-Gallardo, J, Álvarez, C, Asadi, A, Moran, J, and Chaabene, H. Effects of progressed and nonprogressed volume-based overload plyometric training on components of physical fitness and body composition variables in youth male basketball players. J Strength Cond Res 35(6): 1642-1649, 2021-This study examined the effect of 6 weeks of progressed and nonprogressed volume-based overload plyometric training (PT) on components of physical fitness and body composition measures in young male basketball players, compared with an active control group. Subjects were randomly assigned to a progressed PT (PPT, n = 7; age = 14.6 ± 1.1 years), a non-PPT (NPPT, n = 8, age = 13.8 ± 2.0 years), or a control group (CG, n = 7, age = 14.0 ± 2.0 years). Before and after training, body composition measures (muscle mass and fat mass), countermovement jump with arms (CMJA) and countermovement jump without arms (CMJ), horizontal bilateral (HCMJ) and unilateral jump with right leg (RJ) and left leg (LJ), 20-cm drop jump (DJ20), sprint speed (10 m sprint), and change of direction speed (CODS [i.e., T-test]) were tested. Significant effects of time were observed for muscle and fat mass, all jump measures, and CODS (all p < 0.01; d = 0.37-0.83). Significant training group × time interactions were observed for all jump measures (all p < 0.05; d = 0.24-0.41). Post hoc analyses revealed significant pre-post performance improvements for the PPT (RJ and LJ: ∆18.6%, d = 0.8 and ∆22.7%, d = 0.9, respectively; HCMJ: ∆16.4%, d = 0.8; CMJ: ∆22.4%, d = 0.7; CMJA: ∆23.3%, d = 0.7; and DJ20: ∆39.7%, d = 1.1) and for the NPPT group (LJ: ∆14.1%, d = 0.4; DJ20: ∆32.9%, d = 0.8) with greater changes after PPT compared with NPPT for all jump measures (all p < 0.05; d = 0.21-0.81). The training efficiency was greater (p < 0.05; d = 0.22) after PPT (0.015% per jump) compared with NPPT (0.0053% per-jump). The PPT induced larger performance improvements on measures of physical fitness as compared to NPPT. Therefore, in-season progressive volume-based overload PT in young male basketball players is recommended.

Effects of Maturation on Physical Fitness Adaptations to Plyometric Drop Jump Training in Male Youth Soccer Players

Vera-Assaoka, T, Ramirez-Campillo, R, Alvarez, C, Garcia-Pinillos, F, Moran, J, Gentil, P, and Behm, D. Effects of maturation on physical fitness adaptations to plyometric drop jump training in male youth soccer players. J Strength Cond Res 34(10): 2760-2768, 2020-The objective of this study was to compare the effects of maturation on physical fitness adaptations to a twice weekly, 7-week plyometric drop jump training program. Seventy-six young male soccer players (aged 10-16 years) participated in this randomized controlled trial. Before and after the intervention, a physical fitness test battery was applied (countermovement jump; drop jump from 20 to 40 cm; 5 multiple bounds test; 20-m sprint time; change of direction speed; 2.4-km running time-trial; 5 repetition maximum [RM] squat; and maximal kicking distance). Participants were randomly divided into an active soccer-control group (CG) with Tanner stage maturation of 1-3 (CG-early; n = 16) or Tanner stage 4-5 (CG-late; n = 22), and to plyometric drop jump training groups with Tanner stage 1-3 (plyometric jump training [PJT]-early; n = 16) or 4-5 (PJT-late; n = 22). The analysis of variance and effect size (ES) measures revealed that when compared with their age-matched controls, the PJT-early (ES = 0.39-1.58) and PJT-late (ES = 0.21-0.65) groups showed greater improvements (p < 0.05) in sprint time, 2.4-km running time-trial, change of direction speed, 5RM squat, jumping, and kicking distance. The PJT-early exceeded the PJT-late group with greater (p < 0.05) improvements in drop jump from 20 cm (ES = 1.58 vs. 0.51) and 40 cm (ES = 0.71 vs. 0.4) and kicking distance (ES = 0.95 vs. 0.65). Therefore, a 7-week plyometric drop jump training program was effective in improving physical fitness traits in both younger and older male youth soccer players, with greater jumping and kicking adaptations in the less-mature athletes.

Influence of Maturation Status on Eccentric Hamstring Strength Improvements in Youth Male Soccer Players After the Nordic Hamstring Exercise

PURPOSE

This study examined the effects of a 6-week Nordic hamstring exercise (NHE) program in youth male soccer players of less mature (pre-peak height velocity [PHV]) or more mature (mid/post-PHV) status.

METHODS

Forty-eight participants were separated into pre-PHV (11.0 [0.9] y) or mid/post-PHV (13.9 [1.1]) groups and further divided into experimental (EXP) and control groups with eccentric hamstring strength assessed (NordBord) both before and after the training program. Participants in the EXP groups completed a periodized NHE program performed once or twice weekly over a 6-week period.

RESULTS

The NHE program resulted in moderate and small increases in relative eccentric hamstring strength (in newtons per kilogram) in the pre-PHV EXP (d = 0.83 [0.03-1.68]) and mid-PHV EXP (d = 0.53 [-0.06 to 1.12]) groups, respectively. Moderate increases in the same measure were also seen in the between-groups analyses in the pre-PHV (d = 1.03 [0.23-1.84]) and mid-PHV (d = 0.87 [0.22-1.51]) groups, with a greater effect observed in the former.

CONCLUSION

The results from this study demonstrate that a 6-week NHE program can improve eccentric hamstring strength in male youth soccer players, with less-mature players achieving mostly greater benefits. The findings from this study can aid in the training prescription of NHE in youth male soccer players.

Anthropometric variables, propulsive force and biological maturation: A mediation analysis in young swimmers

Youth swimming performance may be influenced by anthropometric and body composition factors during growth. Propulsive force of the arm (PFA) is highly related to swimming performance as 85-90% of the propulsive power comes from the arms. The current study analyzed the mediating effect of biological maturation on the relationship between anthropometric variables and body composition with PFA in young swimmers. A total of 128 swimmers [boys: n = 53, age = 13.6 (1.8) y; girls: n = 75, age = 12.5 (1.8) y] were evaluated. Propulsive force of the arm was estimated by the tethered swimming test. Anthropometric characteristics (body mass, stature, sitting height, arm span, arm muscle area, %body fat, and fat-free mass) were evaluated. Biological maturation was estimated by the age of peak height velocity. Mediation analyses were performed using the Preacher and Hayes bootstrapping method, adjusted for chronological age and sex. All anthropometric and body composition variables, except %body fat, were positively associated with PFA, being mediated by biological maturation. Indirect effects and 95% confidence intervals were: body mass [.20 (.09-.34)], stature [.22 (.11-.43)], arm span [0.17 (.05-.31)], arm muscle area [.74 (.38-1.19)] and fat free-mass [.17 (.05-.34)]. In conclusion, biological maturation mediated the positive associations between body size and composition and PFA in young swimmers.

Effects of Maturation on Physical Fitness Adaptations to Plyometric Jump Training in Youth Females

Romero, C, Ramirez-Campillo, R, Alvarez, C, Moran, J, Slimani, M, Gonzalez, J, and Banzer, WE. Effects of maturation on physical fitness adaptations to plyometric jump training in youth females. J Strength Cond Res XX(X): 000-000, 2019-The aim of this study was to compare the effects of maturation on physical fitness adaptations to plyometric jump training (PJT) in youth females. Jumping, sprinting, change of direction speed, endurance, and maximal strength were measured pre-post 6 weeks of PJT in 7th- and 10th-grade subjects. In the seventh grade, subjects formed a PJT group (Plyo-7, n = 10; age, 12.7 ± 0.6 years; breast maturation stages IV [n = 2], III [n = 7], and II [n = 1]) and an active control group (Con-7, n = 9; age, 12.8 ± 0.6 years; breast maturation stages IV [n = 2], III [n = 6], and II [n = 1]). In the 10th grade, subjects conformed a PJT group (Plyo-10, n = 9; age, 16.3 ± 0.5 years; breast maturation stages V [n = 5] and IV [n = 4]) and an active control group (Con-10, n = 9; age, 16.2 ± 0.5 years; breast maturation stages V [n = 5] and IV [n = 4]). Magnitude-based inferences were used for data analysis, with effect sizes (ESs) interpreted as <0.2 = trivial; 0.2-0.6 = small; 0.6-1.2 = moderate; 1.2-2.0 = large; and 2.0-4.0 = very large. The Plyo-7 and Plyo-10 showed meaningful improvements in all physical fitness measures (ES = 0.21-2.22), while Con-7 and Con-10 showed only trivial changes. The Plyo-7 and Plyo-10 showed meaningful (ES = 0.16-2.22) greater improvements in all physical fitness measures when compared with their control counterparts. The Plyo-10 showed meaningful greater improvements in 20-m sprint, 2-km running time trial, maximal strength, squat jump, and drop jump from 20 cm (ES = 0.21-0.42) when compared with Plyo-7. In conclusion, PJT is effective in improving physical fitness in younger and older female youths. However, greater adaptations were observed in more mature subjects.

The "Journal of Functional Morphology and Kinesiology" Journal Club Series: Highlights of Recent Papers in Pediatric Exercise

We are glad to introduce the ninth Journal Club. This edition is focused on several relevant studies published in the last years in the field of Pediatric Exercise, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport as seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.

A Meta-Analysis of Resistance Training in Female Youth: Its Effect on Muscular Strength, and Shortcomings in the Literature

BACKGROUND

Resistance training is an effective way to enhance strength in female youth but, to date, no researcher has meta-analysed its effect on muscular strength in that population.

OBJECTIVES

This meta-analysis characterised female youths' adaptability to resistance training (RT). A second objective was to highlight the limitations of the body of literature with a view to informing future research.

DATA SOURCES

Google Scholar, PubMed, Web of Science.

STUDY ELIGIBILITY CRITERIA

Resistance training interventions in healthy females with a mean age between 8 and 18 years. Programmes of between 4 and 16 weeks' duration that included a control group.

STUDY APPRAISAL AND SYNTHESIS METHODS

The inverse-variance random effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis whilst accounting for heterogeneity across studies. Effect sizes, calculated from a measure of muscular strength, are represented by the standardised mean difference and are presented alongside 95% confidence intervals.

RESULTS

The magnitude of the main effect was 'small' (0.54, 95% confidence interval: 0.23-0.85). Effect sizes were larger in older (> 15 years; ES = 0.72 [0.23-1.21] vs. 0.38 [- 0.02-0.79]), taller (> 163 cm; ES = 0.67 [0.20-1.13] vs. 0.55 [0.08-1.02]) and heavier (< 54 kg; ES = 0.67 [0.30-1.03] vs. 0.53 [- 0.00-1.06]) participants.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Resistance training is effective in female youth. These findings can be used to inform the prescription of RT in female youth.

A systematic review on the effects of resistance and plyometric training on physical fitness in youth- What do comparative studies tell us?

INTRODUCTION

To date, several meta-analyses clearly demonstrated that resistance and plyometric training are effective to improve physical fitness in children and adolescents. However, a methodological limitation of meta-analyses is that they synthesize results from different studies and hence ignore important differences across studies (i.e., mixing apples and oranges). Therefore, we aimed at examining comparative intervention studies that assessed the effects of age, sex, maturation, and resistance or plyometric training descriptors (e.g., training intensity, volume etc.) on measures of physical fitness while holding other variables constant.

METHODS

To identify relevant studies, we systematically searched multiple electronic databases (e.g., PubMed) from inception to March 2018. We included resistance and plyometric training studies in healthy young athletes and non-athletes aged 6 to 18 years that investigated the effects of moderator variables (e.g., age, maturity, sex, etc.) on components of physical fitness (i.e., muscle strength and power).

RESULTS

Our systematic literature search revealed a total of 75 eligible resistance and plyometric training studies, including 5,138 participants. Mean duration of resistance and plyometric training programs amounted to 8.9 ± 3.6 weeks and 7.1±1.4 weeks, respectively. Our findings showed that maturation affects plyometric and resistance training outcomes differently, with the former eliciting greater adaptations pre-peak height velocity (PHV) and the latter around- and post-PHV. Sex has no major impact on resistance training related outcomes (e.g., maximal strength, 10 repetition maximum). In terms of plyometric training, around-PHV boys appear to respond with larger performance improvements (e.g., jump height, jump distance) compared with girls. Different types of resistance training (e.g., body weight, free weights) are effective in improving measures of muscle strength (e.g., maximum voluntary contraction) in untrained children and adolescents. Effects of plyometric training in untrained youth primarily follow the principle of training specificity. Despite the fact that only 6 out of 75 comparative studies investigated resistance or plyometric training in trained individuals, positive effects were reported in all 6 studies (e.g., maximum strength and vertical jump height, respectively).

CONCLUSIONS

The present review article identified research gaps (e.g., training descriptors, modern alternative training modalities) that should be addressed in future comparative studies.