KNEE POWER IN LOW BACK PAIN SUBJECTS DURING RUNNING

Abstract

The purpose of this study was to examine lower extremity shock absorption between runners with and without low back pain. We compared data from three groups based on low back pain status: current low back pain, resolved pain after a single bout of low back pain and runners who never had low back pain (CTRL). All subjects ran at least 20 km per week and ran on a force treadmill at 3.8 m•s-1 while kinematic and kinetic data were collected. Work was determined from joint power histories during the shock attenuation portion of the stance phase. Individuals with a history of low back pain exhibited less peak knee negative power and negative work suggesting that they exhibited decreased eccentric muscle activity during foot-ground impact. The results of this study suggest that decreased eccentric activity of the muscles crossing the knee joint is associated with individuals who have low back pain and, to a lesser extent, with those who have residual low back pain. We suggest that the decreased eccentric activity can result in the footground impact shock wave moving through the lower extremity with little attenuation to the low back region.