Biomechanical evaluation of a prolonged stooping posture

Abstract

Working at or below knee height for extended period of time with the trunk fully flexed has been known to increase the risk of low back disorders, but the specific biomechanics of this link is not fully developed. Of particular interests include the interplay between the active and passive extensor mechanisms of the low back and muscle fatigue development in stooping. An in vivo experiment was conducted to quantitatively examine the influences of static stooping on the biomechanics of the low back by evaluating the changes in the flexion-relaxation onset angle and the myoelectric activity of back extensors in stooping.