Ability to Predict Impending Volitional Exhaustion Based on Aerobic Capacity

Abstract

Maximal relative oxygen consumption (VO2max), assessed via a treadmill test to volitional exhaustion, is the foremost measure of aerobic capacity in healthy, recreationally active young adults. Habitual exercise may improve the ability to perceive exercise difficulty and predict impending exhaustion. PURPOSE: The primary aim of this investigation was to determine if a correlation existed between VO2max and time to test termination after participants indicated they were 30 s from volitional exhaustion. A secondary aim was to ascertain if participants more accurately predicted impending exhaustion during a repeated trial. METHODS: Participants completed a familiarization trial to minimize learning effects and determine treadmill speed for maximal testing. During the familiarization trial, participants self-selected a zero-grade jogging speed associated with a value of 12-13 on Borg’s 6-20 RPE scale when steady-stated. This speed was used during two maximal tests separated by 36-72 h. During maximal testing, grade was increased 2% every two minutes until volitional exhaustion. VO2max was measured as a 15-breath moving average via a metabolic cart. Participants were instructed before and during testing to tap on the treadmill when they perceived themselves to be 30 s from volitional exhaustion. RESULTS: Thirteen (Females: 8, Males: 5) recreationally active individuals (20.7 ± 1.4 yrs., 72.4 ± 12.3 kg) completed the protocol. Mean VO2max during session 1 (10.00 ± 2.46 min) was 47.0 ± 7.4 ml⋅kg-1⋅min-1, and time to test termination after the tap was 36.2 ± 7.4 s. Mean VO2max during session 2 (10.08 ± 2.38 min) was 47.5 ± 7.7 ml⋅kg-1⋅min-1, and time to test termination after the tap was 40.0 ± 18.5 s. No significant correlation was detected between VO2max and time to test termination after the tap in session 1 (r = -.032, p = .917) or session 2 (r = .315, p = .295). A dependent t-test (t(12) = -.800, p = .439) did not reveal significant differences in time to test termination after the tap between session 1 and session 2. CONCLUSIONS: Aerobic capacity did not affect the ability of healthy, recreationally active young adults to predict impending volitional exhaustion during maximal treadmill running. Time to test termination after the tap did not significantly change during a repeated trial.