Effect of stepping rate on energy costs during StairMaster exercise.
The responses to a self-selected stepping pattern (random) on a StairMaster 4000PT were compared with those obtained in response to the rates established by the manufacturer (cadence) in men (N = 14) and women (N = 14). During the random test the subjects stepped at their own natural, self-selected rate and distance. In cadence trial the subjects were required to step in time with a metronome at a predetermined rates of 60, 77, 95, and 112 steps.min-1. Each trial consisted of four, 5-min continuous workloads during which HRs were recorded and expired air was analyzed using an automated open-circuit gas system each minute. All size dependent variables (i.e., VE and lO2.min-1) as well as relative VO2 (mlO2.kg-1.min-1) were significantly (P < 0.01) higher for the men across all stages and between methods. Although the random test produced slightly higher oxygen consumption values than the cadence trial, these differences were not significant (P > 0.05). The actual METs were significantly (P < 0.01) higher at all stages except at the lowest stepping rate for both methods compared with those estimated by the manufacturer. Equations were established to estimate actual MET costs: Men's METs = 2.675 + 0.935 (rate); women's METs = 2.934 + 0.817 (rate). Cross-validations of 0.975 and 0.957 were obtained on an additional group of men (N = 8) and women (N = 11), respectively.
Butts
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Human Performance Laboratory, University of Wisconsin-LaCrosse, WI 54601.
Dodge
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McAlpine
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D000328:Adult; D000704:Analysis of Variance; D001944:Breath Tests; D002153:Calorimetry, Indirect; D004734:Energy Metabolism; D016552:Ergometry; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012737:Sex Factors; D013997:Time Factors