Prediction of the loading along the leg during snow skiing.

The complete force and moment of each cross section of the leg between the ski boot top and the knee during normal skiing were predicted from measurements of the force and moment under the toe and heel of the boot and the flexion of the ankle. The force and moment components predicted at the base of the boot were significantly different from those predicted at sites of potential injury at the boot top and the knee. The maximum torsional and maximum varus-valgus moments predicted at the knee over all subjects tested were 70 Nm and 149 Nm, which are within the estimated range of the ultimate strength of the knee without support from contracted muscles crossing the knee. Regression analyses were used to find the force components at the base of the boot that best predict the bending and torsional moments at the boot top and knee. The torsional moments at the boot top and knee are best predicted by the medial-lateral force at the toe. The varus-valgus moment at the boot top and knee are best predicted by the resultant medial-lateral force component at the base of the boot. The set of best predictors of the anterior-posterior bending moments at the boot top and knee includes the vertical force at the toe, the vertical force at the heel and the component of the total vertical force directed perpendicular to the leg.