The purpose of this study was to compare two protocols and the resulting VO2 max obtained. In one protocol grade only was used to impose greater workloads; in the other protocol speed only was used to impose greater workloads. In addition, maximum heart rate, perceived general fatigue, leg fatigue and cardiorespiratory fatigue between the two protocols was compared. Thirty apparently healthy subjects, 15 men and 15 women, between 18 and 35 years of age participated; The statistical treatment showed that there was no significant difference in VO2 max between inclined and horizontal running. There was no significant difference in max heart rate, general fatigue, or cardiorespiratory fatigue between the two protocols. Additionally, male subjects perceived that they performed harder on the horizontal protocol and also preferred the horizontal protocol. The females perceived that they performed harder on the inclined protocol and preferred the inclined protocol
