Abstract:

BACKGROUND: Studies showed that maximum shortening velocity of fast and slow muscle are different, mainly because the different myosin heavy chain types, which are expressed by fast and slow muscle, and cause differences in myosin ATPase activity.
OBJECTIVE: To introduce the composition changes of skeletal muscle fibers and myosin heavy chain under different exercises conditions, and to have a deeply understanding of the relationship between exercises training and skeletal muscle contractility.
METHODS: PubMed and Medline springlink database from January 1990 to October 2009 were searched by computer for articles about the skeletal muscle and myosin heavy chain, with the key words of the “skeletal muscle”, “myosin heavy chain”, and “training”, the language was limited to English. Simultaneously, Chinese Journal Full-text database was searched for the articles during the period of January 2000 to October 2009, the key words were “skeletal muscle, myosin heavy chain, and training,” with the language limited to Chinese. Inclusion criteria: the effect of different forms of exercise on skeletal muscle and myosin heavy chain. Exclusion criteria: repeated or similar studies.
RESULTS AND CONCLUSION: The morphological characteristics of myosin: fast and slow muscles contain different types of myosin heavy chain. The effects of exercises on myosin heavy chain are: endurance training can cause muscle myosin heavy chain transformed from the fast to the slow type, which is affected by training time, intensity and age factors; anti-resistance training can enhance fast myosin heavy chain, which at the same time affected by training intensity, and time duration as well; and reduction of exercises mostly will lead to slow myosin heavy chain transformed to the fast type. And resistance strength training can cause skeletal muscle hypertrophied which is showed as muscle fiber myosin heavy chain increased, and muscle fiber transformation expressed as the myosin heavy chain-Ⅱ x (formerly named Ⅱ b myosin heavy chain) transforms to the myosin heavy chain-Ⅱ, and hypoxia training can lead to slow myosin heavy chain transformed to the fast type, while reduction of exercises mostly will lead to slow myosin heavy chain transformed to fast type too.