Effects of upper limb immobilization on isometric muscle strength, movement time, and triphasic electromyographic characteristics

Abstract

The effects of short-term immobilization on isometric muscle strength, movement time, and triphasic integrated electromyographic characteristics were assessed during a simple ballistic elbow flexion and extension movement. The nondominant upper limbs in six subjects (two female, four male) were immobilized in a plaster cast for 14 days. Testing consisted of isometric muscle strength output of elbow flexors and extensors: movement time; and IEMG output of the agonist, antagonist, and second agonist contractions during the ballistic movements. An analysis of variance revealed a decrease in flexor strength of the casted limb (p < .05). Movement time was not significantly slowed. Antagonist IEMG amplitude was decreased (p < .01) during flexion, and agonist (IEMG) amplitude (p < .05) and antagonist IEMG amplitude (p < .05) were diminished during extension of the casted limb. In conclusion, short-term upper limb immobilization affects primarily elbow flexion strength and some IEMG characteristics during a ballistic forearm movement, suggesting an influence on the neuromuscular aspects of the affected muscles.