The aim of this study was to establish the role of maturation on the development of physical performance in adolescent athletes and nonathletes. The total studied sample consisted of 231 participants (131 athletes: 72 boys with an average chronological age of 13.53 ± 0.7 and 59 girls with an average chronological age of 11.97 ± 0.8; 100 nonathletes: 47 boys with an average chronological age of 13.73 ± 0.47 and 53 girls with an average chronological age of 11.93 ± 0.33), distributed according to their biological maturity stage (Pre-, Mid-, and Post-Peak Height Velocity [PHV]) and to their gender. The assessment of physical performance was performed using the following tests: Countermovement jump (CMJ), countermovement jump with arm swing (CMJA), squat jump (SJ), five-jump test (5JT), 5 m sprint (5 m), 10 m sprint (10 m), 20 m sprint (20 m), T-test, Zig Zag, and Slalom. The differences in athletes according to biological maturity were identified in all variables except for 5 m (p = 0.33) and Slalom (p = 0.07), while in nonathletes the differences were found in 5JT (p = 0.01), 5 m (p = 0.02), 10 m (p = 0.01), and 20 m (p = 0.01) tests. Additionally, a significant interaction of gender and biological maturity was detected for CMJ (p = 0.03), CMJA (p = 0.01), and Zig Zag (p = 0.05) in athletes. The findings of the current study confirm the importance of maturity status in the assessment of physical performance. As a consequence, a more rational selection of talented athletes could be provided, also enabling the timely development of physical performance in nonathletes as a “window of opportunity”.

Background: This study aimed to explore the effectiveness of a 12-week circuit training program in improving local muscular endurance in normal-weighted primary school students. Methods: The study involved a parallel-group randomized trial with 606 primary school boys assigned to an experimental or a control group. The participants underwent a 12-week circuit training program that involved multi-joint, total-body workouts using body weight, resistance bands, and medicine ball exercises. The study measured the participants’ local muscular endurance during sit-ups, dynamic trunk extensions on a Roman bench (DTE), and push-ups. Results: After adjusting for the baseline, the treatment–grade interaction was significant for sit-ups (F = 7.74, p < 0.001, η_p² = 0.04), DTE (F = 6.49, p < 0.001, η_p² = 0.03), and push-ups (F = 9.22, p < 0.001, η_p² = 0.05), where the experimental treatment was more beneficial than the control. The treatment effect seemed to vary depending on the individual’s baseline local muscle endurance capacity. As the baseline local muscular endurance values increased, the treatment and grade effects became less beneficial. Conclusion: A 12-week circuit training program involving body weight, resistance bands, and medicine ball exercises suits school-based programs and can improve local muscular endurance in normal-weighted primary school boys. The experimental treatment was more effective than the control, and the individual baseline muscular endurance should be considered when designing training programs.

Children and adults may react differently to warm‐up preservation due to different physical characteristics. This study aimed to: (i) assess the impact of different rewarm‐up routines in swimmers during a transition phase (20–25 min), including passive rest (SWU) or dynamic activities (RWU), on countermovement jump and swimming start performances, and (ii) explore potential RWU adaptations considering maturity offset (peak height velocity—PHV) and sex. Performance was analyzed using mixed effect ANCOVA, considering protocol, maturity offset (pre‐PHV, mid‐PHV, post‐PHV, and adv. post‐PHV), and sex. Results favored RWU over SWU with substantial magnitudes for jump height: pre‐PHV (min‐20, ES = 1.21; min‐25, ES = 1.65), mid‐PHV (min‐20, ES = 1.23; min‐25, ES = 1.14), post‐PHV (min‐20, ES = 1.37; min‐25, ES = 0.73), and adv. post‐PHV (min‐20, ES = 1.03; min‐25, ES = 0.65). Significant interactions at 25 min (p = 0.033, 0.047) showed that RWU outperformed SWU, especially in younger groups (pre‐PHV, mid‐PHV). RWU was superior to SWU for the reactive strength index at 20 min (p = 0.042) and 25 min (p = 0.047), with females having lower RSI than males at 20 min (p = 0.008, p = 0.015) and 25 min (p = 0.049) in later developmental stages. The flight distance (p = 0.009) and horizontal hip velocity (p = 0.014) revealed significant three‐way interactions, with the male adv. post‐PHV group responding better to RWU. Knee angular velocity was also higher after RWU, with male adv. post‐PHV group showing more pronounced improvements (p = 0.016). These results suggest that though RWU had higher influence in male adults, it is a valuable approach for varying ages athletes.

Background: The aim of this study is to investigate the effects of a school-based high-intensity interval training (HIIT) program on quality of life and physical fitness in adolescents. Methods: The study included 60 male adolescents (16.2 ± 0.6 years), randomly assigned to one of two groups: the HIIT group (n = 30) and the control group (CG, n = 30). Participants completed the KIDSCREEN-27 questionnaire to evaluate quality of life and physical fitness tests, including vertical jump, repetitive strength, agility, and flexibility. The experimental program consisted of a 12-week intervention integrated into the warm-up phase of regular physical education (PE) classes. Each PE class lasted 45 min, with the HIIT regimen occupying 10 min of the warm-up phase. The HIIT sessions followed a Tabata-style structure, performed twice weekly. A two-way ANOVA with repeated measures assessed group and time interaction effects. Results: The results revealed changes in physical well-being following the HIIT intervention (p = 0.01) compared to the control group (p = 0.42). The results of the two-way ANOVA with repeated measures revealed interaction effects between group and time for the various fitness tests, countermovement jump (p = 0.04), 4 × 10 m agility test (p = 0.02), medicine ball throw test (p = 0.04), and sit-ups (30 s) (p = 0.01). Conclusions: This study highlights the effectiveness of school-based HIIT in significantly enhancing physical well-being and physical fitness among adolescents.

This study aimed to explore the effects of a single moderate-intensity aerobic endurance running program on the morphological characteristics of normal-weighted and overweighted female adolescents and whether effects differ between individuals of different nutritional statuses. A total of 47 adolescent girls participated in this randomized controlled trial. Before and after 12 weeks of intervention, measurements were obtained for body height, body mass, BMI, triceps, subscapular, abdominal, thigh, and calf skinfolds, and chest, abdominal, thigh, and calf circumference. The total duration of the program was 12 weeks, with a frequency of 2 hours/week (24 sessions). The individual session lasted 60 minutes, and the intensity ranged from 60 % HRmax to 80 %. The findings from the present study suggest that the 12-week aerobic endurance running program induced changes in morphological characteristics of female adolescents. The significant reductions in body mass and BMI were small for normal-weight adolescents (-2,64 % and -3,48 %) and moderate for overweight adolescents (-4,14 % and -4,36 %) following the experimental program. The magnitude of reductions in the skinfold thickness was small for both groups (triceps, subscapular, abdominal, and calf) and moderate for thigh skinfold and a sum of skinfolds in the overweight group. The reductions in the magnitude of all circular measures were small for both groups. It ranged from - 1.59 % to -2.59 % for normal-weight and from -2.54 % to -3.92 % for overweight adolescents, respectively. Additionally, the effects of the applied program seem more favorable to overweight than normal-weight adolescents. This study's current findings indicate that the 12-week aerobic endurance running program is effective due to improvements in morphological characteristics, body mass, and BMI of female adolescents. Additionally, this study's findings show that applied aerobic endurance running program proved more effective for overweight adolescents.

Objectives: This single-arm, pre–post intervention study with a three-month follow-up aimed to determine whether a ten-day outdoor camp combining mixed-modality physical activity and time-restricted feeding elicits positive changes in multiple body-composition outcome measures and whether those changes persist at three-month follow-up. Methods: Forty healthy undergraduates (18 male, 22 female) participated in a 10-day outdoor camp that combined multi-modal physical activities (rock climbing and bouldering, swimming, hiking, applied paddling, survival skills, etc.) with a 13 h daily time-restricted feeding window. Body fat percentage, skeletal muscle percentage, body mass, total body-water percentage, visceral fat level, and skeletal muscle index were measured using the InBody 270 at baseline, immediately post-camp, and at the three-month follow-up. Results: Mixed-effects models with random intercepts for subject revealed significant reductions in body fat percentage (β = −1.63, p < 0.001) and visceral fat level (β = −0.72, p = 0.001), alongside increases in skeletal muscle percentage (β = 1.02, p < 0.001), skeletal muscle index (β = 0.30, p < 0.001), and total body-water percentage (β = 1.19, p < 0.001) from baseline to post-camp; no outcomes differed between baseline and follow-up and no time × sex interactions were observed. Conclusions: These findings indicate that a brief, intensive nature-based intervention can drive rapid, multidimensional improvements in body composition, but structured maintenance is required to sustain benefits.