Effect of Hindlimb Immobilization on the Fatigability of Skeletal Muscle

Document Type

Article

Language

eng

Format of Original

7 p.

Publication Date

5-1983

Publisher

American Physiological Society

Source Publication

Journal of Applied Physiology

Source ISSN

0021-8987

Original Item ID

DOI: 10.1152/jappl.1983.54.5.1242

Abstract

The soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were studied in situ (33.5ºC) after 6 wk of disuse atrophy produced by hindlimb immobilization (IM). IM resulted in depressed peak twitch (Pt) and tetanic (P0) tension as well as a decreased rate of tension development (+dP/dt) and decline (-dP/dt) in the slow-twitch SOL. The fast-twitch EDL was affected to a lesser extent, because only Po (g·cm-2) and Po,-dP/dt (g·cm-2·ms-1) were depressed after IM. Twitch duration, as measured by contraction time and one-half relaxation time, was shortened in the SOL and prolonged in the EDL. In both the fast and slow muscles 30 min of electrical stimulation resulted in a significant decline in Po. Relative to the prefatigued Po, the atrophied and control muscles showed a similar fatigue pattern. This occurred in spite of lower ATP and glycogen concentrations and higher lactate levels in the atrophied muscles. Our results indicate significant impairment of contractile function following IM in fast and slow muscles with preferential alterations in the slow SOL. In addition, despite a lower resting capacity and an increased dependence on glycolysis, contractile properties of atrophied muscles differed little from control muscles in their pattern of response to 30 min of electrical stimulation.

Comments

Journal of Applied Physiology, Vol. 54, No. 5 (May 1983): 1242-1248. DOI.

Link to Full Text

Share

COinS