Levelling-off of Calf Blood Flow and its Relationship to during Walking and Running, and its Relationship to Anaerobic Threshold

抄録

Calf blood flow (CBF), heart rate (HR), whole-body VO₂ were measured in 13 active women (aged 20.8 yrs) while walking or running at various speeds up to near exhaus'tion. CBF during walking increased linearly in relation to speed in the range 60·100 m/min, and thereafter it levelled off. CBF during running showed a small increase up to 180 m/min, then decreased significantly (p<0.01) from 24.51 ml/100ml calf/min to 19.62 ml/100 ml calf/min. VO₂ corresponding to peak CBF (BFpeak-VO₂) averaged 66.39% VO_2max, which was significantly lower (p<0.05) than the anaerobic threshold (AT;74.48% VO_2max) determined using gas exchange parameters. Significant correlation coefficients of 0.695 (p<0.01) and 0.708 (p<0.01) were obtained between BFpeak-%VO₂ and AT-%VO₂, and BFpeak-%VO_2max and AT-%VO_2max. The magnitude of CBF was not correlated significantly with AT or VO₂max. Levelling-off or decrease of CBF at higher speeds, approximately 10% below AT, suggested that an inadequate blood supply will possibly result in mismatching between oxygen delivery and muscle oxygen demand and that this would lead to switching over to anaerobic energy generatlon.