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Eccentric Muscle Control Modeling

  • Graduate Student: Kevin O'Brien
  • Principal Investigator: Dr. James Schmiedeler
  • Team: Kevin O'Brien & Al Olzewski
  • Funding: Indiana CTSI; Craig H. Nelson Foundation; NIH
  • Goal: To explore eccentric muscle control during weight acceptance in locomotion of individuals with incomplete spinal cord injury

Current rehabilitation techniques too often fail to return individuals who have experienced incomplete spinal cord injury to a level of locomotion independence that supports full community ambulation. These techniques typically involve exclusively level-ground locomotion activities, which may not be sufficient to reach the desired level of walking function. Targeting eccentric motor control, which is essential in the weight acceptance phase of walking, may allow patients to recover beyond the limits of current rehabilitation regimens. Downhill walking emphasizes eccentric muscle activity, and downhill training can be relatively easily added to current therapy programs. From models developed using experimental kinematic, kinetic, and EMG data collected from healthy controls and spinal cord injury patients before and after a downhill training program, this research seeks to quantify the effects that targeted eccentric motor control rehabilitation can have on improving locomotion capability.

Joint force and torque dynamics can be calculated directly from the gait analysis. The musculoskeletal system, however, consists of multiple muslces acting across individual joints and often acting across multiple joints. For these reasons, the muscle forces can not be directly calculated and must be simulated using a variety of optimization parameters. Muscles that are lengthening while they are active absorb energy while from the gait, a muscle activity pattern particularly difficult for individuals with incomplete spinal cord injury. In general, abduction of the hip joint and flexion of the knee joint are primarily considered, and muscles that act across these joints are the focus of this research. Nonetheless, by modeling the entire musculoskeletal system, the simulations may provide insight into possible eccentric muscle activity that would not be observable through traditional biomechanical analysis.