The effect of ageing and exercise on skeletal muscle function. Mech Ageing Dev 1984 Oct 15;27(2):161-72
Date
10/15/1984Pubmed ID
6492893DOI
10.1016/0047-6374(84)90041-1Scopus ID
2-s2.0-0021592409 (requires institutional sign-in at Scopus site) 93 CitationsAbstract
The contractile and selected biochemical properties of fast- and slow-twitch skeletal muscle were studied at 9, 18, and 28 months of age in sedentary and regularly exercised rats. The isometric twitch duration was prolonged with aging in both the fast- and slow-twitch muscle. This effect was primarily due to a prolonged one-half relaxation time (1/2RT), which developed late in life. Regular exercise tended to further prolong the twitch duration, particularly in the slow-twitch soleus. Surprisingly, twitch and tetanic tension (Po), peak rate of tension development and decline, and the maximal shortening velocity were all unaltered between 9 and 28 months of age. Furthermore, regular exercise (running or swimming) had little or no effect on these properties. The prolonged 1/2RT with aging could not be explained by a decreased rate of Ca2+ sequestration by the sarcoplasmic reticulum, as the rate of Ca2+ uptake measured in muscle homogenates was unaltered in any of the muscles studied between 9 and 28 months. The degree of muscle fatigue (decline in Po) with 30 min of contractile activity in the slow-twitch soleus was not affected by aging. However, lactate reached two-fold higher levels and glycogen fell to considerably lower levels in the muscles of the old rats. This suggests an increased glycolysis and glycogen utilization during contractile activity in aged rats.
Author List
Fitts RH, Troup JP, Witzmann FA, Holloszy JOAuthor
Robert Fitts PhD Professor in the Biological Sciences department at Marquette UniversityMESH terms used to index this publication - Major topics in bold
Adenosine TriphosphateAging
Animals
Calcium
Glycogen
In Vitro Techniques
Lactates
Lactic Acid
Muscle Contraction
Muscles
Physical Exertion
Rats
