Effect of Alpine Ski Boot Cuff Release on Knee Joint Force During the Backward Fall

Abstract

The modern rigid alpine ski boot has been associated with an increase in severe knee joint injuries. A new design that allows the rear portion of the upper cuff of the boot (rear spoiler) to open when a posterior directed force is applied to it (similar to when a skier falls back on the ski) is investigated. Motion analysis was combined with kinetic measures to estimate the shear and compressive forces at the knee joint using a link-segment model while subjects fell backward to provoke ski boot cuff release. The rear spoiler opening was found to reduce anterior cruciate ligament directed shear force while increasing compressive force at the joint. We conclude that both compressive force and reduced anterior cruciate directed shear force have been associated with protective mechanisms at the knee joint. This occurred over a very brief period of time, however, and the influence this may have on knee injury prevention is discussed.