Abstract
<title>Abstract</title> <p>Background Traditional fragmented training models in collegiate rugby often fail to translate basic fitness improvements into on-field performance. This study developed and evaluated an 8-week closed-loop functional physical training program designed to enhance agility, explosive power, and match-specific performance in collegiate rugby players, addressing the gap between physical conditioning and sport-specific ability. Methods Twenty-four collegiate rugby players were allocated to either a functional training group (FTG, n = 12) or a routine training control group (CG, n = 12) using a computer-generated sequence for group assignment. The FTG underwent an 8-week progressive program integrating core stability, deceleration control, reactive Change of Direction (COD), landing stiffness, and sport-specific running, guided by weekly movement quality thresholds. The CG followed a traditional split-training regimen. Pre-intervention and post-intervention assessments included the movement quality score, 505 COD time, reactive jump index, vertical jump height, 20 m sprint time, and a match involvement index. A two-way repeated-measures Analysis of Variance (ANOVA) was used to analyze group-by-time interactions. Results The FTG demonstrated significantly greater improvements across all primary outcomes compared to the CG (p < 0.05 for all). For the FTG, the 505 COD time improved from 2.69 s to 2.52 s (vs. 2.70 s to 2.61 s in CG), vertical jump height increased from 46.8 cm to 53.6 cm (vs. 47.1 cm to 49.8 cm), and the match involvement index rose from 18.4 to 21.9 (vs. 18.1 to 19.3). The FTG also showed superior performance in match-related transfer indicators, including post-contact reacceleration time (1.31 s vs. 1.42 s) and effective COD completion rate (86.9% vs. 78.6%). Conclusions The closed-loop functional training program, characterized by movement quality control and dynamic load adjustment, effectively improved physical fitness and its transfer to match performance in collegiate rugby players. This model offers a practical, evidence-based approach for pre-season conditioning in team sports, emphasizing the integration of movement quality with physical development. Trial registration Not applicable. This study investigated a sports training program in healthy collegiate athletes and did not involve any clinical treatment, drug, or medical device. According to the journal's policy and the WHO definition of a clinical trial, this study does not qualify as a clinical trial and therefore was not registered.</p>