The Effectiveness of Stability Exercises and Resistance Training in Improving Shoulder Stability and Shoulder Strength in School Rugby Players

Abstract

Background The shoulder joint's high mobility makes it prone to injuries, especially in contact sports like rugby, where shoulder injuries account for 23% of cases. Adolescent players face increased risk due to developmental factors, yet most injury prevention programmes are designed for elite athletes and are too time-consuming for school players. An efficient, evidence-based targeted shoulder stability training tailored for adolescent rugby athletes is needed. This study compares the effects of stability exercises, resistance training, and a combination of shoulder stability and strength in school rugby players over six weeks. Methodology This randomised controlled trial was conducted at a high school’s high-performance centre in Gauteng, supervised by a registered Biokineticist. A total of 160 rugby players aged 13–19 years were recruited, of whom 142 (88.8%) completed all baseline and post-protocol validated testing, yielding a 100% response rate among completers. Participants followed one of three age-appropriate six-week training protocols targeting shoulder stability (u/14–15), strength (u/16–17), or combined stability and strength (u/18–19). The control and intervention groups were divided using an odd and even number system as they wrote their names down, where the odd numbers were the control group and the even numbers were the intervention group. The training, aligned with school schedules, was performed twice weekly with progressive intensity. Results Across all age groups, intervention participants showed significantly greater improvements than controls (p < 0.001). In the stability protocol (u/14–15), the intervention group demonstrated larger gains in the Upper Quarter Y-Balance Test (mean change: left 10.9cm vs 4.4cm; right 9.3cm vs 4.1cm) and in scapular endurance and push-up capacity. In the strength protocol (u/16–17), the intervention group achieved greater improvements in 1-minute push-ups (+8.6 vs +3.5 reps) and 60% body-weight shoulder press (+6.9 vs +3.0 reps). The combined protocol (u/18–19) produced significant increases in both stability (UQYBT left +12.0 vs +3.1 cm; right v +11.2 vs +3.0 cm) and strength measures (isometric pull-up +11.1 vs +2.6 sec; 1- minute push-ups +9.3 vs +2.9 reps; shoulder press +6.1 vs +1.8 reps). Overall, the six-week targeted protocols were effective in improving shoulder stability and strength in adolescent rugby players, with the intervention groups consistently outperforming controls. Conclusion This study highlights the importance of age-specific training for shoulder stability and strength in high school rugby players. Stability exercises benefit younger athletes, and a combined strength and stability training programme is most effective for mid- adolescents and older players. While structured pre-season training can enhance performance and reduce injury risk in a short time frame, factors like individual variability and external environmental factors should be considered. Future research should explore long-term effects and a broader population to refine these protocols further.