It was recently shown in mice that a brief exposure to anabolic steroids recruited new muscle nuclei. The ability to recruit new nuclei is impaired in the elderly, so it might be beneficial to strength train before senescence.ĭoping with anabolic steroids also seem to act partly by recruiting new nuclei. The extra muscle nuclei obtained by a strength training episode seems to be very long lasting, perhaps permanent, even in muscles that are inactive for a long time. Thus, upon retraining the extra nuclei are already there and can rapidly start synthesizing new protein to build muscle mass and strength. Since in vivo imaging has confirmed that cell nuclei are added during strength training and not lost upon subsequent detraining, the nuclei might provide a mechanism for muscle memory.
connective tissue and muscle stem cells called satellite cells. Direct observation indicated that no nuclei are lost under such conditions, and the apoptosis observed in the muscle tissue were demonstrated to occur only in other cell nuclei in the tissue, e.g. Until recently it was believed that during muscle wasting ( atrophy) muscle cells lost nuclei by a nuclear self-destruct mechanism called apoptosis, but recent observations using time lapse in vivo imaging in mice do not support this model. It has often been assumed that each nucleus can support a certain volume of cytoplasm, and hence that there is a constant volume domain served by each nucleus, although recent evidence suggests that this is an oversimplification. During such fiber enlargement muscle stem cells in the muscle tissue multiply and fuse with pre-existing fibers as to support the larger cellular volume. Strength-training increases muscle mass and force mainly by changing the caliber of each fiber rather than increasing the number of fibers. Such multinucleated cells are called syncytia. To support this large volume, the muscle cells are one of the very few in the mammalian body that contain several cell nuclei.
The muscle cells are the largest cells in the body with a volume thousands of times larger than most other body cells. Muscle memory is probably related to the cell nuclei residing inside the muscle fibers, as is described below. The notion of a memory mechanism residing in the muscle fibers might have implications for health related exercise advice, and for exclusion times after doping offences. For strength training this view was recently challenged by using in vivo imaging techniques revealing specific long lasting structural changes in muscle fibers after a strength-training episode. Until recently it was generally assumed that the effects of exercise on muscle was reversible, and that after a long period of de-training the muscle fibers returned to their previous state. Long-term effects of previous training on the muscle fibers themselves, however, have recently also been observed related to strength training. Until recently such effects were attributed solely to motor learning occurring in the central nervous system. The term could relate to tasks as disparate as playing the clarinet and weight-lifting, i.e., the observation that strength trained athletes experience a rapid return of muscle mass and strength even after long periods of inactivity. Muscle memory has been used to describe the observation that various muscle-related tasks seem to be easier to perform after previous practice, even if the task has not been performed in a while. ( Learn how and when to remove this template message) ( September 2013) ( Learn how and when to remove this template message) Please help improve it to make it understandable to non-experts, without removing the technical details.
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