Faculty Collaboration Database

Contractile properties of rat soleus muscle: effects of training and fatique. Am J Physiol 1977 Sep;233(3):C86-91

Date

09/01/1977

Pubmed ID

143894

DOI

10.1152/ajpcell.1977.233.3.C86

Scopus ID

2-s2.0-0017657897 (requires institutional sign-in at Scopus site)   68 Citations

Abstract

The effects of exercise training and fatique on the contractile properties of rat soleus muscles have been investigated. Prolonged exercise, consisting of 2 h or daily treadmill running, induced small but significant decrease in contraction time, one-half relaxation time, and maximum tetanic tension (Po), and increase in the peak rate of tension development (dP/dt) during a twitch, and an increase in maximum shortening velocity (Vmax). The 20% increase in Vmax was proportional to the previously reported increase in actomyosin ATPase induced by 2 h of daily running. These results indicate that prolonged training can induce modifications of the neurally determined contractile properties of skeletal muscle. To investigate the effects of fatigue, soleus muscles were stimulated in situ with 250-ms trains of 100 Hz at a rate of 110 trains per minute for 30 min. This resulted in a 32% decrease in Po, a 48% decline in peak tetanic dP/dt, and a 12% decrease in Vmax in muscles of untrained animals. Muscles that had adapted to exercise were significantly protected against the decrease in Po (only an 8% decrease) and Vmax (no significant decrease) but not against the decline in peak dP/dt.

Author List

Fitts RH, Holloszy JO

Author

Robert Fitts PhD Professor in the Biological Sciences department at Marquette University

MESH terms used to index this publication - Major topics in bold

Animals
Electric Stimulation
Fatigue
Male
Muscle Contraction
Muscle Tonus
Physical Endurance
Physical Exertion
Physical Fitness
Rats
Specific Pathogen-Free Organisms
Time Factors