Immobilization-induced increase in fatigue resistance is not explained by changes in the muscle metaboreflex

Muscle Nerve. 2008 Nov;38(5):1466-1473. doi: 10.1002/mus.21127.

Abstract

Immobilization has been reported to enhance fatigability, which is paradoxical in light of the metabolic and molecular alterations that occur in atrophied muscles. We examined whether the immobilization-induced enhancement in fatigability was associated with attenuation in the muscle metaboreflex response. Ten subjects were examined after 3 weeks of hand-forearm immobilization. The time to task failure of a handgrip contraction (20% intensity) was determined along with heart rate (HR) and mean arterial pressure (MAP) at rest, during the task and during a 2-min postexercise muscle ischemia (PEMI) test that continues to stimulate the metaboreflex. Immobilization decreased strength by 25% (P<0.01) and increased the time to task failure by 21% (P=0.03). However, no changes were observed for the HR and MAP responses to the exercise task or during PEMI (P>0.05). These findings indicate that the augmentation of time to task failure with immobilization is not associated with changes in the pressor or metaboreflex responses.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Baroreflex / physiology*
  • Blood Pressure / physiology
  • Exercise / physiology
  • Fatigue / etiology
  • Fatigue / pathology*
  • Fatigue / physiopathology*
  • Female
  • Hand Strength / physiology
  • Heart Rate / physiology
  • Humans
  • Immobilization / methods*
  • Male
  • Muscle Contraction
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / physiopathology*
  • Time Factors
  • Young Adult