Time Course of Changes in Human Skeletal Muscle Succinate Dehydrogenase and Cytochrome Oxidase Activities and Maximal Oxygen Uptake with Physical Activity and Inactivity

Abstract

Succinate dehydrogenase (SDH) and cytochrome oxidase activities in the lateral vastus of the human quadriceps femoris muscle together with total body VO2 max were followed during an 8-10 week period of endurance training (n = 13) and a successive 6 week period without training (n = 8). During the training period there was a gradual increase in both VO2 max and muscle oxidative enzyme activities, all being significantly different from the pre-training levels after 3 weeks of training. After 8 weeks of training VO2 max was 19%, vastus lateralis SDH 32%, and cytochrome oxidase activity 35% above the pre-training levels respectively. 6 weeks post training VO2 max was still 16% above the pre-training level, and not significantly different from the level at the end of training (p greater than 0.2). In contrast vastus lateralis SDH activity had returned to the pre-training level. Cytochrome oxidase activity had returned to the pre-training level within two weeks post-training. The significantly faster post-training decline in skeletal muscle oxidative enzyme activities in contrast to that of the VO2 max indicates that an enhancement of the oxidative potential in skeletal muscle is not a necessity for a high VO2 max. Moreover, the fast return to the pre-training level of both SDH and cytochrome oxidase activities indicate a high turnover rate of enzymes in the TCA cycle as well as the respiratory chain.

Effect of 3 weeks of detraining on the resting metabolic rate and body composition of trained males

“…This may explain why our current ®ndings along with those of Allen (1989), Henriksson & Reitman (1977) and Moore et al (1987), whose subjects displayed mean V Ç O 2 max values of 56, $ 43 and $ 46 ml.kg…”

Long term adaptation to electrically induced cycle training in severe spinal cord injured individuals

“…59 However, it seems likely that upon spinal cord injury overall oxidative capacity in paralysed muscle deteriorates relatively more than cardiopulmonary function and that, accordingly, maximum oxygen uptake can be improved by restoration of muscle. Furthermore, maximal heart rates obtained during exercise is approximately 120 beats per minute in tetraplegics and 150 in paraplegics and thus lower than seen in able-bodied subjects.…”

“…The increase in CS occurred in our study quite rapidly compared to other adaptations to exercise, corresponding to what is seen during training of extremely inactive bedridden able-bodied subjects. 59 Studies on electrically stimulated (10 Hz, 8 h/day) rat fast twitch muscle also showed a steep increase of 36% within the ®rst 10 to 20 days of stimulation but thereafter an increase of only 26% until day 30 to 40 where a plateau was reached. 60 This corresponded with the fact that a plateau was reached after 3 months in the present study.…”

“…This ®nding agrees with studies exploiting the e ect of endurance training and detraining in the healthy man. 59 From these studies it could be concluded that maximal oxygen uptake in healthy man is limited by cardiopulmonary capacity rather than by peripheral skeletal muscle oxidative capacity. In the present study muscle mass, as indicated by thigh circumference measurements, probably continued to increase after CS concentration had reached a plateau.…”

Benefits of Physical Exercise in Patients with Chronic Kidney Disease and Hemodialysis: A Mini Review

“…On the other hand, aerobic exercise has been shown to improve the efficacy of mitochondrial oxidative metabolism of muscle [15] and to increase the muscular mitochondrial volume [16]. A metaanalysis by Smart et al [17] observed the effects of different types of exercise on the improvements of various physical fitness tests such as maximal oxygen consumption and muscle strength, they also observed improvements on energy intake and significant reductions in serum concentrations of C-reactive protein and IL-6, they conclude that physical training was shown to be a safe intervention with no deaths associated with exercise.…”