[Effect of endurance training on the compositions of fiber types and myosin light chains in muscles under disuse atrophy].
The effects of endurance training on the compositions of fiber types (Type I and Type II) and myosin light chains (MLC) of the muscle under disuse atrophy (soleus) were studied. The hindlimbs of adult Wistar rats were immobilized on the ankle joint in an extended position for 2 weeks. The rats were then trained by a treadmill for 0, 1, 2, 4, and 8 weeks after the release from fixation. The wet weight and cross sectional area of soleus muscle significantly decreased, and a significant decrease in the percentage of slow type of MLC was also observed. In the running group, the weight and area recovered more rapidly than those of the control. The compositions of fiber types and MLC were not significantly different between the control and running groups. Type II fiber appears to have a compensatory function of Type I fiber. These results suggested that endurance training would promote the recovery from malfunction in muscle atrophy induced by disuse.
Takanashi
G
G
Department of Orthopaedic Surgery, St. Marianna University School of Medicine, Kanagawa, Japan.
D000818:Animals; D005081:Exercise Therapy; D007103:Immobilization / Q000502:physiology; D009132:Muscles / Q000033:anatomy & histology*; D009133:Muscular Atrophy / Q000473:pathology / Q000628:therapy*; D009218:Myosins / Q000032:analysis*; D010807:Physical Endurance / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D009218:Myosins