Relationship between muscle fiber composition, capillary supply, oxidative enzyme activity and aerobic work capacity in middle- and long-distance runners.
- VernacularTitle:中・長距離ランナーにおける筋線維組成，毛細血管，酸化酵素活性と有酸素的作業能との関係
- Author:
RYOUICHI MITSUZONO
;
SHIGERU KATSUTA
;
YOUJI KANAO
;
KEN-ICHI TABUCHI
;
JUN NAGAI
- Publication Type:Journal Article
- Keywords:
capillary supply;
SDH activity;
VO2@AT;
middle and long-distance runners
- From:Japanese Journal of Physical Fitness and Sports Medicine
1986;35(4):182-191
- CountryJapan
- Language:Japanese
-
Abstract:
It was the purpose of this study to examine the property of skeletal muscle fiber in middle- and long-distance runners, and to evaluate the relationship between the property of skeletal muscle fiber and aerobic work capacity.
Biopsy samples were taken from M, vastus lateralis of 23 middle- and long-distance runners, and analyzed for muscle fiber composition, capillary supply and SDH activity. Aerobic work capacity was measured on a treadmill with continuous method.
The mean value for % ST in M. vastus lateralis was 61.3%, and the muscle fiber distribution showed the tendency of slow type. The crosssectional area of ST and FT fibers ranged approximately from 3, 000 μm2 to 13, 000 μm2, and the cross-sectional area of ST fiber tended to be larger than that of FT fiber. The mean values for CD, C/F ratio, and CC (/ST) as capillary supply were 279/mm2, 1.62 and 5.7, respectively. The mean value for SDH activity was 5.86 μmoles/g/min, and was lower than reported previously for elite runners. In addition, SDH activity correlated with % ST and CC (/ST) (r=0.480, p<0.05, r=0.640, p<0.01) . On the other hand, the mean value for VOG2max was 68.5 ml/ kg/min (4, 066 ml/min), while VO2@AT averaged 45.9 ml/kg/min (2, 756 ml/min) . And it was found that VO2max and VO2@AT correlated significantly with % ST, CC (/ST) and SDH activity. Particular, VO2 max was most strongly related to SDH activity (r=0.612, p<0.01) .
The results of this study suggest that in regard to middle- and long-distance runners, structural characteristics of the ST fiber and capillary are some of the indispensable factors to regulate such a functional property as SDH activity and that the distinctive characteristics of the skeletal muscle fiber might possibly influence aerobic work capacity to a great extent.
