Serial effects of high-resistance and prolonged endurance training on Na+-K+ pump concentration and enzymatic activities in human vastus lateralis

The purpose of this study was to compare two contrasting training models, n amely high-resistance training and prolonged submaximal training on the exp ression of Na+-K+ ATPase and changes in the potential of pathways involved in energy production in human vastus lateralis. The high-resistance trainin g group (VO2peak = 45.3 +/- 1.9 mL kg(-1) min(-1), mean +/- SE, n = 9) perf ormed three sets of six to eight repetitions maximal, each of squats, leg p resses and leg extensions, three times per week for 12 weeks, while the pro longed submaximal training group (VO2peak = 44.4 +/- 6.6 mL kg(-1) min(-1), n = 7) cycled 5-6 times per week for 2 h day(-1) at 68% VO2peak for 11 wee ks. In the HRT group, Na+-K+ ATPase (pmol g(-1) wet wt), measured with the H-3-ouabain binding technique, showed no change from 0 (289 +/- 22) to 4 we eks (283 +/- 15), increased (P < 0.05) by 16% at 7 weeks and remained stabl e until 12 weeks (319 +/- 19). For prolonged submaximal training, a 22% inc rease (P < 0.05) was observed from 0 (278 +/- 31) until 3 weeks (339 +/- 29 ) with no further changes observed at either 9 weeks (345 +/- 25) or 11 wee ks (359 +/- 34). In contrast to high-resistance training, where a 15% incre ase (P < 0.05) was observed, only in the maximal activity of phosphorylase, prolonged submaximal training resulted in increases in malate dehydrogenas e. beta-hydroxyl-CoA dehydrogenase, hexokinase and phosphofructokinase. In contrast to high-resistance training which failed to result in an increase in VO2peak, prolonged submaximal training increased VO2peak by approximate to 15% Only for prolonged exercise training was a relationship observed for VO2peak and Na+-K+-ATPase (r = 0.59; P < 0.05). Correlations between VO2pe ak and mitochondrial enzyme activities were not significant (P > 0.05) for either training programme, it is concluded that although both training prog rammes stimulate an up-regulation in Na+-K+ ATPase concentration, only the prolonged submaximal training programme enhances the potential for beta-oxi dation, oxidative phosphorylation and glucose phosphorylation.