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 × 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.
Bibliographical noteFunding Information:
This work was supported by the National Science Foundation REU Program under grant #0452503 to Marquette University.
- Muscle fatigue