The effect of exercise hyperpnea on gross efficiency and anaerobic capacity estimates during a 3-min cycle time trial

This study aimed to analyze the effect of exercise-induced hyperpnea on gross efficiency (GE) and anaerobic capacity estimates during a self-paced 3-min supramaximal cycle time trial (TT). Fourteen highly-trained male cyclists performed 7×4-min submaximal stages, a 6-min passive rest, a 3-min TT, a 5-min passive rest, and a 6-min submaximal stage. Three models were based on the 7×4-min linear regression extrapolation method, using (1) the conventional model (7-YLIN); (2) the same 7-YLIN model but correcting for the additional ventilatory cost (i.e., hyperpnea) (7-YLIN-V-cor); and, (3) accounting for linearly declining GE during the TT (7-YLIN-D). The other three models were based on GE from the last submaximal stage, using the conventional model (GELAST) and the same modifications as described for 7+YLIN, i.e., (1) GELAST, (2) GELAST-V-cor, and (3) GELAST-D. The GELAST model generated 18% higher values of anaerobic capacity than the 7-YLIN model (P<0.05). During the TT, the hyperpnea corrected model (i.e., 7-YLIN-V-cor or GELAST-V-cor) generated, compared to the respective conventional model (i.e., 7-YLIN or GELAST), ~0.7 percentage points lower GE and ~11% higher anaerobic capacity (all, P<0.05). The post-TT GE was 1.9 percentage points lower (P<0.001) and the 7-YLIN-D or GELAST-D model generated, compared to the respective conventional model, a lower GE (~1.0 percentage points) and ~17% higher anaerobic capacity during the TT (all, P<0.05). In conclusion, the correction for a declining GE due to hyperpnea during a supramaximal TT resulted in an increased required total metabolic rate and anaerobic energy expenditure compared to the conventional models.