Aerobic and anaerobic performance capacity of junior athletes

The determinants of aerobic and anaerobic performance capacity of 58 junior athletes were studied. The main parameters studied were maximal oxygen uptake (maxVo₂) in leg and arm work, the percentage of slow-twitch muscle fibers (%ST fibers) and succinate dehydrogenase activity (SDH) in m. vastus lateralis (VL), m. gastrocnemius c.l. (GL) and m. deltoideus (D), vertical velocity (Vv) and muscular power (MP) during running up the stairs, total (TLF) and relative (RLF) isometric force of extensor muscles of both legs, blood lactate after maximal leg and arm work and relative power index (RPI). The junior endurance athletes, cross-country skiers and long-distance runners, had highest maxVo₂ of 75 mlxkg⁻¹ xmin ⁻¹. The female cross-country skiers had 10% lower maxVo₂ than male skiers. In arm work maxVo₂ of t e male and.female junior skiers was 77% and 74% as compared with maxVo₂ in leg work, respectively. The junior long-distance runners had the highest oxidative capacity both in m. VL and m. GL according to the mean values of %ST fibers and SDH activity. The junior short-distance runners performed best in the running velocity test (1.47 mxsec⁻¹) and they also had the highest blood lactate (11.8 mM) after maximal leg work. The junior skijumpers had significantly higher TLF and RLF than the other junior athletes. The age of the male junior athletes was found to correlate significantly with maxVo₂ (r = .39), %ST fibers (r = .25), SDH activity (r = -.29) and RPI (r = .28). When the effect of age of the male juniors was kept constant by using the partial correlation methods maxvo2 was found to correlate significantly with RLF (r = -.37) and RLF with RPI (r = .33).