In-school resistance training improves physical fitness in pubertal girls: a randomized controlled trial

Abstract

Background: Physical fitness is a powerful marker of current and future health in children and adolescents. However, global reports have long documented a persistent decline, with an even greater decline among girls. This study aimed to examine the impact of school-based resistance training (RT) on physical fitness and body composition in pubertal girls. Methods: A randomized controlled trial was conducted over eight weeks, with sessions held three times a week. RT program was conducted during physical education classes. A total of 79 girls from four schools were randomly assigned to one of four groups: control group (CON, n = 21), traditional strength training group (TST, n = 20), plyometric training group (PT, n = 19), and combined training group (CT, n = 19). Pre- and post-intervention assessments were performed by evaluating body composition, musculoskeletal fitness, cardiorespiratory fitness, speed and agility. Results: Significant improvements were observed in TST for push-ups, 1 min sit-ups, standing long jump (SLJ) and 50 m sprint (p < 0.05). PT and CT groups displayed valuable improvement in push-ups, SLJ, 50 m sprint and Illinois changes of direction test (p < 0.05). Notably, CT yielded a significant increase in the 20 m shuttle run test (p < 0.001). However, non-significant changes in body composition were observed across intervention groups. Conclusion: RT program implemented during physical education classes was effective in improving physical fitness. Each RT modalities offering unique advantages. Clinical trial number: ChiCTR2500103789; Retrospectively registered on 5/6/2025.