Comparative effects of flywheel and traditional resistance training on reactive strength and multidirectional COD in...

This study compared the effects of flywheel resistance training (FRT) versus traditional resistance training (TRT) on reactive strength, dynamic balance, and sport-specific change-of-direction (COD) ability in elite badminton players.

Twenty-four athletes (mean age: 21.2 ± 2.2 years) were randomly allocated to an FRT group (n = 12) or a TRT group (n = 12). Over 6 weeks, both groups performed twice-weekly sessions of squats, deadlifts, and lunges at a rating of perceived exertion ≈8. Performance was assessed before and after the intervention using the SEMO agility test, modified 5-10-5 COD test, 10-m sprint, reactive strength index (RSI), and Y-Balance test. Data were analyzed with a two-way mixed ANOVA (p < 0.05).

Mixed ANOVA revealed significant main effects of time for the SEMO test, modified 5-10-5 COD test, and 10-m sprint (all p < 0.001, η² = 0.56-0.79), indicating performance improvements at post-test in both training groups. No significant group × time interactions were observed for these variables (p = 0.07-0.23). Within-group effect sizes for these speed and COD measures were large in the FRT group (SEMO: Cohen's d = 1.01; 5-10-5: d = 1.21; 10-m sprint: d = 1.27) and ranged from small to large in the TRT group (d = 0.40-0.87). For RSI, both the main effect of time and the group × time interaction were significant (p < 0.001, η² = 0.90 and 0.66, respectively). Within-group effect sizes were large in the FRT group (d = 2.43) and moderate in the TRT group (d = 0.79). Y-Balance Test improved over time for both dominant and non-dominant limbs (p < 0.001, η² = 0.53-0.57), with no significant group × time interaction (p > 0.75).

These findings suggest that FRT may provide additional advantages over TRT in enhancing reactive strength and COD ability, likely due to eccentric overload-induced neuromuscular adaptations. However, both training modalities were similarly effective in improving dynamic balance. These findings have practical implications for coaches: incorporating twice-weekly FRT into badminton-specific conditioning may optimize deceleration mechanics and multidirectional COD and improve transfer of strength gains to on-court performance.