The present investigation was undertaken to examine whether maximal oxygen uptake (VO2max) and anaerobic threshold (AT) measured during incremental treadmill exercise would be affected by the exercise protocol in trained and untrained individuals. Fifteen untrained men, 10 untrained women, and 12 trained individuals participated in this study. The Astrand, Bruce, and Costill/Fox protocols were selected for comparison. Each subject was tested using all three protocols and the three tests were conducted in a randomized counterbalanced order. During each test, oxygen uptake was measured every 30 s and the test was terminated according to the standard criteria. The VO2max was determined by averaging the two consecutive highest measurements, whereas AT was determined using ventilatory parameters following the V-slope technique. The Astrand, Bruce, and Costill/Fox protocols produced test durations of 9.8 (SEM 0.5), 12.4 (SEM 0.4), and 4.9 (SEM 0.3) min, respectively, in the untrained men, 9.0 (SEM 0.8), 11.0 (SEM 0.6), and 5.3 (SEM 0.6) min, respectively, in the untrained women, and 14.5 (SEM 0.5), 17.0 (SEM 0.5) and 10.4 (SEM 0.4) min, respectively, in the trained men. In the untrained men and women, no differences in VO2max were observed among the three different protocols, but AT was lower when using the Bruce compared to the Astrand protocol. In the trained men, VO2max and AT were lower when using the Bruce protocol than either the Astrand or Costill/Fox protocols. In conclusion, VO2max measured during treadmill exercise is not affected by the protocol of the test and using a running protocol of short duration (i.e. about 5 min) could be a time-efficient way of assessing VO2max in healthy untrained subjects. In trained subjects, however, a protocol consisting of running with small increments in gradient is effective in eliciting a higher VO2max. The lower AT associated with the Bruce protocol seen in both untrained and trained groups suggests this aerobic parameter is protocol dependent and this protocol dependency is not affected by training status.

The present study was undertaken to examine the validity of using the OMNI scale of perceived exertion to regulate intensity during extended exercise periods. Forty-eight subjects (24 male, 24 female) were recruited and each subject completed a maximal graded exercise test (GXT) and two 20-min submaximal exercises. During the GXT, ratings of perceived exertion (RPE) as well as oxygen uptake (VO(2)) and heart rate (HR) equivalent to 50 and 70% of maximum VO(2) (VO(2max)) were estimated. During each submaximal exercise, subjects were instructed to produce and maintain a workload equivalent to the RPE estimated at 50 or 70% VO(2max), and VO(2) and HR were measured every 5 min throughout the exercise. Of the 48 subjects, 12 (6 male and 6 female) performed both the estimation and production trials on a treadmill (TM/TM), 12 (6 male and 6 female) performed both the estimation and production trials on a cycle ergometer (C/C), 12 (6 male and 6 female) performed the estimation trial on a treadmill and the production trial on a cycle ergometer (TM/C), and 12 (6 male and 6 female) performed the estimation trial on a cycle ergometer and the production trial on a treadmill (C/TM). No differences in VO(2) between the estimation and any 5 min of the production trial were observed at either intensity in TM/TM and C/C. No differences in HR between the estimation and any 5 min of the production trial were also observed at 50% VO(2max) in TM/TM and at both 50 and 70% VO(2max) in C/C. However, HR was higher at 20th min of the production trial at 70% VO(2max) in TM/TM. Both the VO(2) and HR were generally lower in TM/C and higher in C/TM. However, these differences diminished when values were normalized using VO(2max) of the same mode that other groups had attained. These data suggest that under both intra- and intermodal conditions, using the OMNI perceived exertion scale is effective not only in establishing the target intensity at the onset of exercise, but also in maintaining the intensity throughout a 20-min exercise session.

The purpose of this investigation was to examine the validity of regulating exercise intensity using ratings of perceived exertion (RPEs) during arm crank and leg cycle exercise at 50 and 70% peak oxygen consumption (VO2peak). Ten men and seven women [26 (1) years old; mean (SE)] participated in this study. Each subject completed a maximal estimation trial and two submaximal exercise bouts (production trials) on both an arm and leg ergometer. During each maximal estimation trial, subjects were asked to give a RPE for each stage of the exercise. RPEs, heart rates (HR), and power outputs (PO) equivalent to 50 and 70% VO2peak for each exercise mode were then estimated from plots of RPE versus oxygen consumption (VO2), HR versus VO2, and PO versus VO2, respectively. During the submaximal trials, subjects were instructed to select workloads on an arm and leg ergometer that produced the previously estimated RPEs. Comparisons were made for VO2, HR, and PO between the estimation and production trials for each mode at each exercise intensity. HR did not differ between the trials at either 50 or 70% VO2peak during arm and leg ergometry. In addition, VO2 and PO did not differ between the trials at either 50 or 70% VO2peak during arm ergometry and at 50% VO2peak during leg ergometry. However, these two parameters were lower (P < 0.05) during the production trial [1.88 (0.15) l x min(-1) and 89.1 (10.1) W, respectively] as compared to the estimation trial [2.08(0.14) l x min(-1) and 102.4 (6.5)W, respectively] during leg ergometry at 70% VO2peak. In conclusion, using RPEs to regulate exercise intensity is physiologically valid during arm ergometry at both 50 and 70% VO2peak and during leg ergometry at 50% VO2peak. However, this prescriptive approach remains questionable during leg cycle exercise at 70% VO2peak.

An exercise regimen in which intensity varies exerts no added effect on metabolic and perceptual responses during exercise as long as the average intensity is kept the same. However, VAR resulted in a greater [latin capital V with dot above]O2 after exercise, and this augmented postexercise oxygen consumption may be mediated in part by elevated plasma [La].

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