Knee load and muscle activity during exercises in rising.

Knee joint loading and the level of knee muscle activation during rising exercises have been evaluated and methods have been developed for such studies. Floor-to-foot forces were recorded using a force-measuring platform. The loading moment of force representing the resistance for the knee joint was calculated. It was shown that the initial knee loading moment with much flexed knees was high at large knee angles. The loading moment showed a marked decrease with decreasing knee angles. For small knee angles there was no resistance to knee extension. Muscular activity level was studied using EMG. The levels of activity in the quadriceps muscles were high at large knee angles and low at small angles. The hamstrings and gastrocnemius showed only low activity. The magnitude of change in knee extension resistance due to adaptive adjustment of the exercise device was mapped. These rising exercises will increase strength mainly for large knee angles and only for quadriceps muscles.