The Effects of an Injury Prevention Program in an Aquatic Environment on Landing Forces: 1611 Board #7 May 28, 1

Lower extremity musculoskeletal injuries, such as ACL injuries, account for a majority of sports and recreational related injuries and are of major concern to the physically active population. Exercise-based injury prevention programs (IPP) can improve landing technique and reduce injury risk. Injury prevention programs performed in an aquatic-based environment may potentially elicit the same improvements as land-based programs, but in an environment with less external stress to the joints. PURPOSE: Examine the effects of a six-week aquatic-based IPP on landing technique as measured by peak vertical ground reaction forces (VGRF). We hypothesized that the aquatic-based IPP would reduce VGRF, and thus improve landing technique. METHODS: 15 healthy, physically active females (age: 20.6±2.1y; mass: 62.02±8.18kg; height: 164.74±5.98cm) volunteered to participate. All participants completed an aquatic-based IPP three times a week for six weeks in the pool. The IPP was modified from land-based IPPs to be able to be performed in the pool while including balance, strengthening, flexibility and plyometric exercises. We conducted a within-subject analysis of variance for each limb to evaluate the average peak VGRF before (PRE), after (POST) and 4 months following (RET) the intervention (α<0.05). All participants performed three trials of a standardized jump landing task at PRE, POST, and RET while landing with both feet on a non-conductive force plate that measured VGRF at 1000 Hz. A customized software program calculated peak VGRF between initial ground contact (VGRF>10N) and take-off (VGRF<10N) of the landing task. Peak VGRF values were normalized by body weight (N). RESULTS: We observed that the aquatic-based IPP significantly reduced VGRF scores between PRE (Right peak VGRF (= 2.67 ± .71%BW; Left= 2.70 ± .85%BW) and POST (Right= 2.23 ± .59%BW; Left= 2.24 ± .81%BW), and POST and RET (Right = 1.85 ± .89%BW Left= 1.65 ± .72%BW)(P <0.01). CONCLUSIONS: The aquatic-based IPP improved landing technique as evident by peak VGRF. These findings demonstrate the feasibility of an IPP in an aquatic-environment and result in decreased VGRF and internal LE stress moments on joints, such as the knee, and can be used to reduce overall LE musculoskeletal injuries.