Energy expenditure with indoor exercise machines
A. I. Zeni, M. D. Hoffman and P. S. Clifford
Sports Performance and Technology Laboratory, Medical Colloege of Wisconsin, Milwaukee, USA.
OBJECTIVE--To compare the rates of energy expenditure at given rating of
perceived exertion (RPE) levels among 6 different indoor exercise machines.
DESIGN--Repeated measures design. PARTICIPANTS--Healthy young-adult
volunteers, including 8 men and 5 women. INTERVENTIONS--Subjects underwent
a 4-week habituation period to become familiar with the RPE scale and
exercise on an Airdyne, a cross-country skiing simulator, a cycle
ergometer, a rowing ergometer, a stair stepper, and a treadmill. Following
habituation, each subject completed an exercise test with each exercise
machine. The exercise test comprised 3 stages of 5 minutes at self-selected
work rates corresponding to RPE values of 11 (fairly light), 13 (somewhat
hard), and 15 (hard). Oxygen consumption, from which the rate of energy
expenditure was calculated, was measured during the last minute of each
5-minute exercise stage. Heart rate was measured during the last minute of
each stage of the exercise test, and blood lactate levels were obtained
immediately after each exercise stage. MAIN OUTCOME MEASURE--Rate of energy
expenditure at specified RPE values. RESULTS--Rates of energy expenditure
at a given RPE varied by 1093 kJ/h (261 kcal/h) for the exercise machines.
The treadmill induced higher (P < .05) rates of energy expenditure for
fixed RPE values than all other exercise machines. The cross-country skiing
simulator, rowing ergometer, and stair stepper induced higher (P < .05)
rates of energy expenditure than the Airdyne and cycle ergometer. Heart
rate varied significantly (P < .01) among exercise machines, with the
highest values associated with the treadmill and the stair stepper. Lactate
concentration varied significantly (P = .004), with highest values
associated with use of the stair stepper and the rowing ergometer.
CONCLUSIONS--Under the conditions of the study, the treadmill is the
optimal indoor exercise machine for enhancing energy expenditure when
perceived exertion is used to establish exercise intensity.
