The Effects of Endurance Training on Muscle Fibre Types and Enzyme Activities

Abstract

Practitioners and scientists have demonstrated great interest in the physiological and biochemical effects of endurance training on the results of the marathon run. It is well documented that athletes with a large proportion of slow twitch and fast twitch aerobic skeletal muscle fibre, high metabolic enzyme activities and concentrations, large mitochondria concentration and, of course, the ability to increase the power output generated for a given rate of oxygen consumption and energy expenditure, are generally highly successful distance runners. Aerobic and endurance training have been shown to bring about significant adaptations to the skeletal muscle and its inclusions as well as to the delivery system. In particular, enzyme activity levels are readily mutable, mitochondrial concentrations increase, and some evidence suggests that the fibre distribution is changed. This article briefly reports on changes in skeletal muscle brought about by endurance training and those changes that appear most effective in yielding success in endurance events.

Urine melatonin and citrate excretion during the elite swimmers’ training season

“…However, the highest citrate total sum was found at the beginning stage after the vacation period. As aerobic training progressed from the beginning to the macrocycle I stage, the citrate total sum significantly decreased and was in agreement with the point of view that endurance exercise improves the oxidative metabolic capacity (Taylor and Bachman 1999;Tang et al 2006;Daussin et al 2008;Iaia et al 2010).…”

Aging Thyroarytenoid and Limb Skeletal Muscle: Lessons in Contrast

“…Proposed relationship between hormonal changes and muscle loss 17,19,20,142 Decline in number of sex hormone receptors in larynx with age 153,154 No studies examining shifts in hormone levels with morphological changes in TA Physical Activity Resistance exercise increases mass and strength 74,76,77,[160][161][162] Direct relationship between exercise and mass unable to be examined Endurance training increases mitochondrial volume density 160,162,[163][164][165][166] No data on disuse and atrophy Disuse associated with atrophy 172 limitation likely comes about due to changes in the size and makeup of motor units as well as the loss and atrophy of muscle fibers. 84 Strength reductions in aged limb skeletal muscle are also well documented.…”

“…Resistance exercise has been consistently linked with increases in muscle mass and strength, 74,76,77,[160][161][162] whereas endurance training has been associated with increases in mitochondrial volume density and a possible shifting of fiber types toward a more oxidative profile. 160,[162][163][164][165][166] Exercise mediates these changes at the cellular level by shifting levels of anabolic and GHs, modifying neuronal input, heightening enzymatic activity, and enhancing antioxidant defenses. 19,74,[167][168][169][170] Apart from structured programs of exercise, there is also evidence to suggest that general levels of physical activity may be predictive of muscle mass in the elderly population.…”

Monitoring chronic physical stress using biomarkers, performance protocols and mathematical functions to identify physiological adaptations in rats

“…in white-fast muscle fibre contraction and glycolytic enzymes). 34 On the other hand, we also expected an increase in LM intensity after endurance training, but the aerobic capacity was significantly unchanged. Thus, while the monotonous training induced an increase in free fatty acids and glycogen stores, the aerobic performance (% of bw) evaluated using LM was attenuated.…”