Daily physical activity levels in preadolescent boys related to $$\dot V_{O_{2max} } $$ and lactate threshold

Summary The purpose of this study was to investigate the physical activity levels in eleven 9–10 year old boys with reference to aerobic power or lactate threshold (LT). Daily physical activity levels were evaluated from a HR monitoring system for 12 h on three different days.\(\dot V_{O_{2max} } \),\(\dot V_{O_2 }\)-HR relationship and LT were determined by the progressive treadmill test. LT was 36.7±3.1 ml · kg⁻¹ · min⁻¹ and 71.0±6.6%\(\dot V_{O_{2max} } \). Mean total time of activities with HR above the level corresponding to 60%\(\dot V_{O_{2max} } \) (T-60%) and that above LT (T-LT) were 34±7 and 18±7 min, respectively.\(\dot V_{O_{2max} } \) (ml · kg⁻¹ · min⁻¹) correlated significantly with T-60% (p<0.01), while no significant relationship was found with LT in ml · kg⁻¹ · min⁻¹. In conclusion, longer daily physical activities at moderate to higher intensity for preadolescent children seem to increase\(\dot V_{O_{2max} } \) rather than LT.