トレッドミル走における持続時間と生理学的応答の変動 Variability of time to exhaustion and physiological responses to treadmill running

The purpose of this study was to assess whether intraindividual variability in run time to exhaustion is related to Vo_2max, HRmax, vVT (running velocity at VT), vVo_2max (running velocity at Vo_2max), and running economy (Vo_2 at 268 m・min^-1 running velocity). The subjects were nine trained university runners. An 8-13 repeated incremental treadmill test (test 1) and another maximal treadmill running test at v Vo_2max to measure the tLIM (run time to exhaustion) at Vo_2max (test 2) were given to each subject at the same time and the same day of the week over 8-13 weeks. These treadmill running tests (tests 1 and 2) were performed at constant temperature (20±0.5℃) and humidity (50±2%) conditions and the same analyzers were used for measuring the Vo_2 (test 1). The mean coefficient of variation (CV) of each subject in run time to exhausion, Vo_2max (ml・kg^1・min^1), HRmax, vVT, vVo_2max, running economy and tLIM at Vo_2max were within the ranges 3.1-6.1%, 4.0-7.6%, 1.0-3.3%, 2.2-5.6%, 1.5-3.5%, 3.6-7.1%, 9.5-32.7%, respectively. It was difficult to explain an intraindividual variability in run time to exhaustion by the variation in Vo_2max, vVT and running economy, except in one subject. Therefore, it is speculated that intraindividual variability in run time to exhaustion in the 8 subjects might have been due to daily changes in peripheral fatigue of the legs, psychological factors (duration of tension and motivation), and anaerobic capacity.