Variation in limb support influences the time to task failure for a postural contraction

J Mot Behav. 2009 Oct;41(5):393-5. doi: 10.3200/35-09-003.

Abstract

The authors compared the time to task failure and muscle activation for a sustained isometric submaximal contraction with the dorsiflexor muscles when the support of the foot varied while supporting an inertial load (position task). Participants performed a supported position task (n = 8) or an unsupported position task (n = 15) while maintaining a constant angle at the ankle with an inertial load equivalent to 20% of maximal isometric contraction torque until task failure. The time to failure for the supported position task (M = 15.4 min, SD = 6.8 min) was longer than for the unsupported position task (M = 10.0 mn, SD = 6.2 min, p = .01). Electromyographic activity of the tibialis anterior differed between tasks (Session x Time, p = .028). Increasing foot support during a position task decreased muscle fatigability and altered activation of the primary agonist indicating the importance of limb support to minimize fatigue during prolonged activation of the dorsiflexor muscles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Braces
  • Electromyography
  • Female
  • Foot / physiology
  • Humans
  • Isometric Contraction / physiology*
  • Leg / physiology
  • Male
  • Muscle Fatigue / physiology*
  • Muscle, Skeletal / physiology*
  • Posture / physiology
  • Range of Motion, Articular
  • Reference Values
  • Task Performance and Analysis
  • Time Factors
  • Weight-Bearing*
  • Young Adult