Resumen de Oxygen Uptake, Heart Rate, and Ratings of Perceived Exertion at the PWC
Michelle Mielke, Terry J. Housh, C. Russell Hendrix, Clayton L. Camic, Jorge M. Zuniga, Richard J. Schmidt, Glen O. Johnson
The purpose of the present study was to examine the oxygen uptake ([latin capital V with dot above]o2), heart rate (HR), and ratings of perceived exertion (RPE [OMNI-Leg 0-10]) responses during continuous 1-hour cycle ergometer rides at the PWC[latin capital V with dot above]o2 (physical working capacity at the oxygen consumption threshold). Eight subjects (mean age ± SD = 23 ± 3.2 years) performed a maximal test to exhaustion for the determination of [latin capital V with dot above]o2peak and ventilatory threshold (VT). The subjects also performed 4 randomly ordered 8-minute workbouts at different power outputs (ranging from 84 to 245 W) to determine the PWC[latin capital V with dot above]o2 and a continuous 1-hour cycle ergometer ride at the PWC[latin capital V with dot above]o2 during which [latin capital V with dot above]o2, HR, and RPE data were collected every 2 minutes. The PWC[latin capital V with dot above]o2 (114 ± 39 W) and VT (133 ± 44 W) were not significantly different and occurred at 56 and 63% [latin capital V with dot above]o2peak, respectively. Linear regression showed that the slope coefficients for the [latin capital V with dot above]o2, HR, and RPE vs. time relationships for the continuous 1-hour workbouts were significantly greater than zero. Furthermore, a t-test about a single mean indicated that the mean slope coefficient for the HR vs. time relationship was significantly greater than 0.1 bpm·min-1 (the rate of increase in HR that can be maintained for an 8-hour day). The results of this study indicated that PWC[latin capital V with dot above]o2 could be maintained for an extended period. However, the maximal power output associated with steady state [latin capital V with dot above]o2, HR, and RPE responses was overestimated. The mean increase in [latin capital V with dot above]o2 during the continuous 1-hour ride was 270 mL, which suggested that the PWC[latin capital V with dot above]o2 may demarcate the moderate from heavy exercise domains. The mean HR slope coefficient of 0.3 bpm·min-1 indicated that the power output at the PWC[latin capital V with dot above]o2 could likely be maintained for greater than 2 hours.
