Faculty Collaboration Database

Muscle fatigue with prolonged exercise: contractile and biochemical alterations. Am J Physiol 1982 Jan;242(1):C65-73

Date

01/01/1982

Pubmed ID

6120654

DOI

10.1152/ajpcell.1982.242.1.C65

Scopus ID

2-s2.0-0020006440 (requires institutional sign-in at Scopus site)   89 Citations

Abstract

Alterations in the contractile and biochemical properties of fast and slow skeletal muscle were studied in rats following a prolonged swim to exhaustion. The exercise produced glycogen depletion (less than 1 mg/g tissue) in muscles representative of all three fiber types; the isometric contractile properties were altered in the 84% type I soleus (SOL) and the 60% type IIa extensor digitorium longus (EDL) but not in the 100% type IIb superficial region of the vastus lateralis (SVL). Peak tetanic tension (Po) and the rate of tension development and decline all decreased after prolonged exercise in both the SOL and the EDL. The maximal isotonic shortening velocity was highly correlated with the myofibrillar ATPase activity, and both were relatively resistant to fatigue. Furthermore, the Ca2+ sensitivity of the myofibrils was unaffected by exercise in both fast and slow muscle. The Ca2+ uptake capacity of the sarcoplasmic reticulum (SR) was reduced in both the SOL and the fast-twitch type IIa deep region of the vastus lateralis, whereas the SR ATPase activity was unchanged. Our findings provide evidence that prolonged exercise produces alterations in contractile and biochemical properties of type I and IIa but not type IIb fibers and that muscle fatigue as measured by a decline in Po is not necessarily correlated with glycogen depletion.

Author List

Fitts RH, Courtright JB, Kim DH, Witzmann FA

Author

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

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

Adenosine Triphosphatases
Animals
Biological Transport, Active
Ca(2+) Mg(2+)-ATPase
Calcium
Calcium-Transporting ATPases
Fasting
Female
Glycogen
Muscle Contraction
Muscle Relaxation
Muscles
Myofibrils
Physical Exertion
Rats
Rats, Inbred Strains
Sarcoplasmic Reticulum