Fee, Lawrence L., Richard M. Smith, and Michael B. English. Enhanced ventilatory and exercise performance in athletes with slight expiratory resistive loading. J. Appl. Physiol. 83(2): 503-510, 1997.We determined the cardiorespiratory and performance effects of slight (1.5-3.0 cmH₂O) expiratory resistive loading (ERL). Twenty-eight highly fit [peak O₂ uptake (O_{2 peak}) = 63.6 ± 1.3 ml · kg¹ · min¹] athletes (age = 33.5 ± 1.3 yr) performed paired O_{2 peak} cycle ergometer tests (control vs. ERL). End-expiratory lung volume was separately determined in a subset of subjects (n = 12) at steady-state 75% maximum power output (PO_max) and was found to increase (0.67 ± 0.29 liter) with ERL. In the O_{2 peak} tests, peak expiratory pressure at the mouth, mean inspiratory flow, minute ventilation, and O₂ pulse were greater with ERL at every intensity level (i.e., 75, 80, 85, and 90% 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. Increased O₂ pulse with ERL at comparative workloads suggests that stroke volume was augmented with ERL. Also, with ERL, athletes attained higher O_{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 lung volume in response to slight ERL during strenuous exercise served to attenuate both airflow and blood flow limitations, which enhanced exercise capacity.