Muscle redundancy does not imply robustness to muscle dysfunction

J Biomech. 2011 Apr 29;44(7):1264-70. doi: 10.1016/j.jbiomech.2011.02.014. Epub 2011 Mar 21.


It is well-known that muscle redundancy grants the CNS numerous options to perform a task. Does muscle redundancy, however, allow sufficient robustness to compensate for loss or dysfunction of even a single muscle? Are all muscles equally redundant? We combined experimental and computational approaches to establish the limits of motor robustness for static force production. In computer-controlled cadaveric index fingers, we find that only a small subset (<5%) of feasible forces is robust to loss of any one muscle. Importantly, the loss of certain muscles compromises force production significantly more than others. Further computational modeling of a multi-joint, multi-muscle leg demonstrates that this severe lack of robustness generalizes to whole limbs. These results provide a biomechanical basis to begin to explain why redundant motor systems can be vulnerable to even mild neuromuscular pathology.

Publication types

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

MeSH terms

  • Biomechanical Phenomena
  • Cadaver
  • Central Nervous System / pathology
  • Electrophysiology
  • Fingers / physiology*
  • Humans
  • Leg / physiology*
  • Muscle Contraction / physiology*
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / pathology*
  • Muscle, Skeletal / physiology*
  • Software
  • Tendons / pathology