Presidential Closing Remarks 12:05 PM – 12:15 PM: Immediately Following President's Lectures ROOM: Ballroom 2/3 and Ballroom 1: D-17 Free Communication/Slide – Sport Biomechanics II THURSDAY, JUNE 1, 2006 1:00 PM – 2:30 PM ROOM: 402
Lower extremity mechanics during weightbearing are often implicated in the etiology of knee injuries including patellofemoral pain and ACL rupture. However, analysis of these mechanics requires costly instrumentation, time, and space. Due to these limitations, practicing clinicians are generally unable to characterize the mechanics of the lower extremity during dynamic activities. Two-dimensional (2D) images recorded by a digital camera during single leg squats reveals the frontal plane projection angle (FPPA) of the knee. Previous studies demonstrate that this 2D value is associated with greater knee valgus and external rotation angles during single leg landings. However, it is unclear to what extent the FPPA is related to lower extremity energetics during such activities.
PURPOSE: To describe the association between the 2D FPPA during single leg squats and hip and knee j oint moments and mechanical work during single leg landings.
METHODS: 20 healthy subjects performed five single leg squats and five single leg landings using their dominant leg. The 2D FPPA was recorded during each squat trial and 3D kinematic and kinetic data were determined for each landing trial. Pearson correlation coefficients were calculated between the FPPA and selected 3D energetics variables from the two conditions.
CONCLUSION: 2D analysis of single leg squats appears to offer insight into the kinetics and energetics associated with single leg landings. Specifically, individuals who demonstrate greater 2D knee valgus during single leg squats are likely to place greater demands on their hip abductors, external rotators, and muscles with knee frontal plane moment arms during single leg landings. Additionally, subjects who squat with smaller projected frontal plane deviations are likely to experience smaller knee frontal and transverse plane moments during landing, which are commonly associated with knee injury.