Purpose: Plyometric exercises are incorporated in anterior cruciate ligament injures of the knee (ACL) injury prevention programs that have effectively decreased risk factors for anterior cruciate ligament injures of the knee injuries, but the impact on the rate of isometric torque development of the musculature of the knee is unclear. The purpose of this study was to determine the effects of a 6-week plyometric program pulled from a commonly utilized anterior cruciate ligament injures of the knee injury prevention program on rate of isometric torque development (RTD) in healthy active females.
Methods: College-aged participants were randomly split into two different groups (16-plyometric training and 15-control). Plyometric exercises included 180° jumps, bounding for distance, bounding in place, broad jump-stick, cone jumps, hop - hop stick, jump into bounding, jump - jump - jump vertical jump, mattress jumps, scissors jump, single-legged jumps for distance, squat jumps, step-jump up-down-vertical jump, tuck jumps, and wall jumps. Participants in the training group performed the exercises three times a week on alternating days, for 30-minute sessions. All participants performed a vertical jump measurement and completed maximum voluntary isometric contractions (MVICs) of ankle plantar flexion, knee extension, and knee flexion rate of torque development.
Results: There was a main effect of session for plantar flexion rate of torque development time windows and vertical jump. The analysis revealed no significant differences for group by session interactions for any other rate of torque development measurement or the vertical jump.
Conclusions: Plyometric exercises utilized from an anterior cruciate ligament injures of the knee injury prevention program did not change lower body isometric torque development or vertical jump height of active females. Since the plyometric training did not improve vertical jump, the training may not have been performed vigorous enough for the participants to cause a neuromuscular adaptation. Based on findings, 6-weeks of plyometric training from an isolated ACL injury prevention program should not be used to increase the vertical jump of healthy, active females.
Doeringer JR, Johnson S, Norcorss M, Hoffman M. Plyometric Exercises from a Knee Anterior Cruciate Ligament Prevention Program on the Rate of Isometric Torque Development and Vertical Jump Height. The Internet Journal of Allied Health Sciences and Practice. 2017 Dec 22;16(1), Article 6.