The influence of speed, grade and mass during simulated off road bicycling

The purpose of this investigation was to examine the effects of bicycle mas s, speed, and grade on oxygen consumption (VO2), heart rate (HR), and ratin gs of perceived exertion (RPE) during a simulated off-road riding paradigm. Nine adult subjects with mean +/- SD age, mass, and VO2, max of 26.1 +/- 5 .6 years, 71.7 +/- 7.5 kg, 56.6 +/- 5.2 ml . kg(-1). min(-1), respectively, were trained to ride a fully suspended Trek Y-22 mountain bike on a treadm ill with a 3.8 cm bump affixed to the belt. Riders completed a maximum of n ine separate trials encompassing three different bike masses(11.6, 12.6 and 13.6 kg), 3 speeds (2.7, 3.6 and 4.5 m . s(-1)), and 3 grades (0, 2.5, and 5%). Throughout a trial, bike mass and speed remained constant while ridin g grade was increased every 5 min. During simulated off-road riding on a fu lly suspended mountain bike, increases in speed and grade significantly inc reased VO2 heart rate, and RPE. Increases in bike mass had no significant e ffects on VO2 heart rate or RPE. In addition, speed and grade changes inter acted to differentially affect VO2 heart rate, and RPE at all speeds and gr ades. (C) 2000 Elsevier Science Ltd. All rights reserved.