We use three-dimensional kinematics and forces measured during movement to characterize the dynamics of walking and other activities. By combining these data with computer simulations of movement, we are discovering the fundamental principles that govern movement and are gaining insight into a variety of clinical problems, including patellofemoral pain and movement disorders associated with cerebral palsy and stroke. We have our own Motion Lab in the Clark Center, and we collaborate with leading motion capture centers including the Biomotion Lab at Stanford, the Gait Analysis Laboratory at Packard Children's Hospital, Children's Memorial Medical Center in Chicago, Gillette Children's Hospital, Shriners Hospital in Sacramento, Connecticut Children's Medical Center, and Motion Analysis Corporation.

Arnold, Liu, Schwartz, Ounpuu, Delp. "The role of estimating muscle-tendon lengths and velocities of the hamstrings in the evaluation and treatment of crouch gait." Gait and Posture, 2005. (Download PDF file)

Arnold, Liu, Schwartz, Ounpuu, Dias, Delp. "Do the hamstrings operate at increased muscle–tendon lengths and velocities after surgical lengthening?" Journal of Biomechanics, 2005. (Download PDF file)

Goldberg, Ounpuu, Arnold, Gage, Delp. "Kinematic and kinetic factors that correlate with improved knee flexion following treatment for stiff-knee gait."Journal of Biomechanics, 2006. (Download PDF file)