Enhanced ventilatory and exercise performance in athletes with slight expiratory resistive loading

Fee, Lawrence L., Richard M. Smith, and Michael B. English.Enhanced ventilatory and exercise performance in athletes withslight expiratory resistive loading. J. Appl.Physiol. 83(2): 503-510, 1997.We determined thecardiorespiratory and performance effects of slight (1.5-3.0cmH₂O) expiratory resistiveloading (ERL). Twenty-eight highly fit [peakO₂ uptake(O_{2 peak}) = 63.6 ± 1.3 ml · kg¹ · min¹]athletes (age = 33.5 ± 1.3 yr) performed pairedO_{2 peak} cycle ergometer tests (control vs. ERL). End-expiratory lung volume wasseparately determined in a subset of subjects(n = 12) at steady-state 75% maximumpower output (PO_max) and wasfound to increase (0.67 ± 0.29 liter) with ERL. In theO_{2 peak}tests, peak expiratory pressure at the mouth, mean inspiratory flow, minute ventilation, and O₂ pulsewere greater with ERL at every intensity level (i.e., 75, 80, 85, and90% PO_max). Increased minute ventilation was largely due to a trend toward increased tidal volume(P < 0.05 at 80%PO_max).O₂ uptake was greater at 90%PO_max with ERL. IncreasedO₂ pulse with ERL at comparativeworkloads suggests that stroke volume was augmented with ERL. Also,with ERL, athletes attained higherO_{2 peak} (63.0 ± 1.4 vs. 60.1 ± 1.3 ml · kg¹ · min¹)and greater PO_max (352.0 ± 9.9 vs. 345.7 ± 9.5 W). We conclude that elevated end-expiratory lungvolume in response to slight ERL during strenuous exercise served toattenuate both airflow and blood flow limitations, which enhancedexercise capacity.