Field measurements in snow skiing injury research.

Field measurements during skiing experiments simultaneously recorded the complete excitation of the toe and heel of one foot, the absolute spatial orientation of the pelvis and the foot, muscle activity at the hip, knee and ankle and the complete rotation of the femur relative to the tibia across the knee in three test subjects. Data were transmitted from test subjects during the skiing experiments by a 100K bits-1. PCM-FM system and recorded in digital form. Analyses of field data show the magnitude of the loading applied to the lower extremity during normal skiing often exceeds the expected, quasi-static ultimate strength of the tibia. Anterior-posterior bending of approximately 600 Nm has been recorded during skiing without binding release or injury to the test subjects. The standard heel binding design can not effectively control the bending moment in the lower extremity during skiing. Longitudinal rotation across the knee was in-phase with, though not proportional to, the applied torsion at the foot by the ski.