Intermodal comparison of energy expenditure at exercise intensities corresponding to the perceptual preference range.

PURPOSE: This study compared the rate of energy expenditure among six popular exercise machines at intensities corresponding to ratings of perceived exertion (RPE) for fairly light (RPE-11), somewhat hard (RPE-13), and hard (RPE-15) in 9 healthy men and 10 healthy women. METHODS: A maximal exercise test on each exercise machine was used to anchor the Borg 15-point category scale. Subjects performed three submaximal exercise tests at selected RPEs on a treadmill, stair-stepper, cycle ergometer, rowing ergometer, cross-country ski simulator, and rider. The submaximal tests on each exercise device were performed in random order and were 6 min in duration with 15-min rest between trials. Oxygen uptake, heart rate, and blood lactate concentration were measured during the final 2 min of each exercise intensity. RESULTS: Energy expenditure at each RPE was highest on the treadmill and ski simulator in men, and on the treadmill, ski simulator, and rowing ergometer in women. Energy expenditure in men and women at all RPEs was lowest on the rider and cycle ergometer. Energy expenditure at a given RPE was greater in men than women on all exercise machines, but men and women used a similar percentage of their machine specific peak oxygen uptake at each RPE on all machines. Heart rate was generally similar among the machines and between both men and women at each RPE. CONCLUSIONS: Our results indicated that there are large differences in energy expenditure between exercise machines and between men and women at intensities perceived to be fairly light, somewhat hard, and hard. Consequently, subjects can expend more calories at the same RPE during treadmill and ski simulator exercise, for example, than during exercise with other devices. This may have important implications for the health benefits of different exercises and in promoting long term exercise adherence.

Children's OMNI scale of perceived exertion: mixed gender and race validation.

PURPOSE: The newly developed Children's OMNI Scale of Perceived Exertion (category range: 0 to 10) was validated using separate cohorts of female and male, African American and white subjects. Each of the four cohorts contained 20 clinically normal, nonobese children, 8-12 yr of age. METHODS: A cross-sectional, perceptual estimation paradigm using a single multi-stage cycle ergometer test protocol was used. Oxygen uptake (VO2; mL x min(-1)), heart rate (HR; beats x min(-1)) and ratings of perceived exertion for the overall body (RPE-Overall), legs (RPE-Legs), and chest (RPE-Chest) were determined at the end of each continuously administered 3-min power output (PO) (i.e., 25, 50, 75, and 100 W) test stage. RESULTS: The range of responses over the four POs for all cohorts was VO2: 290.8 to 1204.0 mL x min(-1); HR: 89.2 to 164.4 beats x min(-1); and RPE-Overall, RPE-Legs, and RPE-Chest: 0.85 to 9.1. First-order correlation and linear regression analyses were performed for each cohort separately and the total sample using a repeated measures paradigm over the four POs. For all correlation/regression paradigms RPE-Overall, RPE-Legs, and RPE-Chest distributed as a positive linear function of both VO2 and HR; r = 0.85 to 0.94; P < 0.01. Differences between RPE-Overall, RPE-Legs, and RPE-Chest were examined with ANOVA for the repeated measures paradigm. RPE-Legs was higher (P < 0.01) than RPE-Chest and RPE-Overall at 25, 50, 75, and 100 W. RPE-Chest did not differ from RPE-Overall at 25 and 50 W but was lower (P < 0.01) than RPE-Overall at 75 and 100 W. CONCLUSION: The psycho-physiological responses provide validity evidence for use of the Children's OMNI Scale over a wide range of dynamic exercise intensities.