Injury Prevention Programs Based on Flywheel vs. Body Weight Resistance in Recreational Athletes

Monajati, A, Larumbe-Zabala, E, Sampson, MG, and Naclerio, F. Injury prevention programs based on flywheel vs. body weight resistance in recreational athletes. J Strength Cond Res 35(2S): S188-S196, 2021-This study compares the effect of an isoinertial flywheel technology vs. a traditional gravity-dependent exercise protocol on modifiable factors associated with the incidence of hamstring strain (HAM) and anterior cruciate ligament (ACL) injuries. Furthermore, the effect on repeated sprint ability was also considered. Eighteen recreationally trained volleyball players completed one of the following 6-week protocols: (a) flywheel (FY) included 3 exercises using a YoYo isoinertial-squat machine and 3 exercises with a Versa-Pulley isoinertial device, and (b) gravity-dependent (GT) involved 6 similar exercises with no external resistance (participants' body weight). Both programs consisted in 2 sessions·wk-1 performing 2 sets of 8 repetitions with 2 minutes of rest. Outcomes included a 10-second tuck jump assessment (TJA), landing knee valgus score, hamstring and quadriceps concentric and eccentric isokinetic 60°·s-1 peak torque, optimal peak torque localization, conventional and functional hamstring-to-quadriceps ratio, and 30-m repeated shuttle sprint ability (RSSA) test. FY improved TJA (-2, interquartile range [IQR] = -3 to -1) and valgus (-1, IQR = -1 to 0) scores, hamstring eccentric (20.37, 95% confidence interval [CI] = 9.27-31.47 N·m) and concentric (17.87, 95% CI = 0.40-35.34 N·m) peak torque, as well as the RSSA (-0.28, 95% CI = -0.45 to -0.10 seconds), whereas GT only improved hamstring eccentric peak torque (21.41, 95% CI = 9.00-33.82 N·m). A 6-week protocol using flywheel technology seems to elicit better positive adaptations to protect athletes from HAM and ACL injuries and to enhance RSSA performance compared to exercising with no external resistance other than athletes' body weight.