Previous research suggests high impact forces generated during landings contribute to noncontact anterior cruciate ligament (ACL) injuries. In women, neuromuscular differences appear to modify the ability to dissipate landing forces when compared to men. This study examined peak vertical impact forces (Fp) and rate of force development (RFD) following a 9-week, low-intensity (simple jump-landing-jump tasks) and volume (number of foot contacts per workout) plyometric-based knee ligament injury prevention (KLIP) program. Female subjects were randomly assigned into control (n = 14) and treatment (n = 14) groups. Treatment subjects attended KLIP sessions twice a week for 9 weeks, and control subjects received no intervention. Ground reaction forces (Fp and RFD) generated during a step-land protocol were assessed at study onset and termination. Significant reductions in Fp (p = 0.0004) and RFD (p = 0.0205) were observed in the treatment group. Our results indicate that 9 weeks of KLIP training altered landing strategies in women to lower Fp and RFD. These changes are considered conducive to a reduced risk of knee injury while landing.
(C) 2004 National Strength and Conditioning Association