Sagittal plane trunk orientation is a better predictor of the knee extensor moment during squatting than tibia orientation

It has been reported that squatting with the knees forward of the toes increases stress on the knee. A limitation of previous studies in this area is that the influence of shank position has been studied without consideration of trunk position, which has been shown to reduce the knee extensor moment during squatting. The purpose of this study was to determine which segment (trunk vs shank) is most influential with respect to predicting the knee extensor moment during squatting. Our results confirm that the trunk and shank have an opposing relationship with respect to the knee extensor moment during squatting. However, sagittal plane trunk posture appears to be more influential.