MUSCLE ENZYME-ACTIVITIES AND FIBER COMPOSITION (M-VASTUS-LATERALIS) AND EFFICIENCY OF THE CARDIORESPIRATORY SYSTEM IN CROSS-COUNTRY SKIERS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 32  (3) , 272-280
Abstract
Male cross-country skiers (14) (class I and II, average age 20.5 yr) were examined by biochemical and histochemical methods. The activity of selected enzymes of energy metabolism and the percentage ratio of different types of muscle fibers (m. [musculus] vastus lateralis) were assessed. The maximum values of the cardiorespiratory system and postloading pH and blood lactate were determined after performance on a treadmill. The mitochondrial enzyme activities were relatively high, with a considerable scatter in the values of HOADH [hydroxyacyl-CoA dehydrogenase] activity. The glycolytic enzyme activities were on the same level as in subjects not engaged in sports. The percentage composition of muscle fibers was as follows: FG [fast glycolytic], 7.56%; FOG [fast oxidative glycolytic], 30.65%; and SO [slow oxidative], 61.79%. O2 consumption .ovrhdot.VO2 max kg was 67.44 ml/min, pulse O2 was 24.76 ml, postload pH was 7.24, and blood lactate concentration was 6.98 mmol/l. There was positive correlation between CS [citrate synthase] enzyme activity and O2 uptake (.ovrhdot.VO2 max), pulse O2 and percentage of SO muscle fibers. The mean values in the athletes examined in this study correspond to values of middle-distance runners.