Neuromuscular constraints on muscle coordination during overground walking in persons with chronic incomplete spinal cord injury

Clin Neurophysiol. 2014 Oct;125(10):2024-35. doi: 10.1016/j.clinph.2014.02.001. Epub 2014 Feb 14.


Objective: Incomplete spinal cord injury (iSCI) disrupts motor control and limits the ability to coordinate muscles for overground walking. Inappropriate muscle activity has been proposed as a source of clinically observed walking deficits after iSCI. We hypothesized that persons with iSCI exhibit lower locomotor complexity compared to able-body (AB) controls as reflected by fewer motor modules, as well as, altered module composition and activation.

Methods: Eight persons with iSCI and eight age-matched AB controls walked overground at prescribed cadences. Electromyograms of fourteen single leg muscles were recorded. Non-negative matrix factorization was used to identify the composition and activation of motor modules, which represent groups of consistently co-activated muscles that accounted for 90% of variability in muscle activity.

Results: Motor module number, composition, and activation were significantly altered in persons with iSCI as compared to AB controls during overground walking at self-selected cadences. However, there was no significant difference in module number between persons with iSCI and AB controls when cadence and assistive device were matched.

Conclusions: Muscle coordination during overground walking is impaired after chronic iSCI.

Significance: Our results are indicative of neuromuscular constraints on muscle coordination after iSCI. Altered muscle coordination contributes to person-specific gait deficits during overground walking.

Keywords: Modules; Motor control; Muscle coordination; Spinal cord injury; Walking.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Electromyography
  • Female
  • Humans
  • Leg / physiopathology*
  • Male
  • Middle Aged
  • Movement Disorders / etiology
  • Movement Disorders / physiopathology*
  • Muscle, Skeletal / physiopathology*
  • Spinal Cord Injuries / complications
  • Spinal Cord Injuries / physiopathology*
  • Walking / physiology*
  • Young Adult