Abstract

The purposes of this study were to examine these questions: (1) Does equivalent external work elicit equivalent physiological responses? and (2) Is equivalent external work subjectively perceived as equivalent? Seven healthy women aged 20 to 27 years served as subjects. Equivalent power outputs (59 watts) were applied on the bicycle ergometer at 50, 60, 70 and 80 rpm with apporopriate resistances and on the treadmill at 81, 89, 97, and 108 meters/minute. Since work on the treadmill is affected by a subjects body weight, the slope of the treadmill was individually determined prior to each session using the following formula: percent grade=100 kpm/)body weight times total revolutions in 1 minute times belt length in meters). Following a 5 minute warm-up at 25 watts, subjects exercised for 5 minutes at the experimental workrate (59 watts). Ventilation volume, oxygen consumption, heart rate and rating of perceived exertion (RPE), as determined with the Borg scale, were collected during the fifth minute at 59 Watts. In general, higher pedalling rates on the bicycle ergometer and walking speeds on the treadmill elicited greater cardio-respiratory and RPE responses than an equivalent workrate at slower speeds. These data suggest that exercise should not be prescribed in terms of an absolute workrate without regard to the speed at which the work is performed. It suggests that at the start of a program, the speed of work should be slow to reduce cardiorespiratory stress, particularly for individuals at high risk for coronary heart disease. In addition, it suggests that individuals using electro-magnetic or constant load ergometers should be constantly monitored for rpm to avoid undesired physiological responses. Verf.-Referat