Alterations in anaerobic threshold as the result of endurance training and detraining

Abstract

The response of anaerobic threshold (AT) to endurance training and detraining was studied in 21 males (X̄ age = 25 yr). Members of the exercise group trained on a cycle ergometer at 80% of maximal oxygen uptake (V̇o_2max) for 30 min four times per week for 9 wk. Nine weeks of detraining followed. A step-wise incremented cycle ergometer test was used to measure maximal and submaximal values of metabolic variables at 3-wk intervals. The criterion for determination of the onset of metabolic acidosis was a systematic increase in the ventilatory equivalent for O₂ (V̇_E/V̇o₂) without an increase in the ventilatory equivalent for CO₂ (V̇_E/V̇co₂). Significant increases and decreases of V̇o_2max for the exercise group during training and detraining, respectively, were revealed by ANOVA. Following 9 wk of training, elevations of 70.4% and 19.4% had occurred in AT expressed as absolute V̇o₂ (AT 1·min⁻¹) and percent of V̇o_2max (AT-V̇o₂), respectively. The latter change was not statistically significant. Losses of training gains in AT (1·min⁻¹) were significant after 6 and 9 wk of detraining. The results of this study indicate that 9 wk of training is of sufficient duration to cause a significant alteration in AT. Loss of this training gain occurs rapidly and appears to be similar to changes in V̇o_2max.