Same effort on a rower or bike instead of a run: same workout?

Moyna and colleagues (Dublin City University) compared the rate of energy expenditure on six popular exercise machines at intensities rated fairly light (RPE 11), somewhat hard (RPE 13) and hard (RPE 15) on the Borg 15-point category scale.

Nine healthy men and ten healthy women first did a maximal test on each machine to anchor the scale, then three 6-min submaximal bouts at the set RPEs on a treadmill, stair-stepper, cycle ergometer, rowing ergometer, cross-country ski simulator and a "rider", in random order with 15 min rest between trials; VO2, heart rate and lactate were measured over the last 2 min.

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; it was lowest on the rider and cycle ergometer in both sexes. Men expended more energy than women at a given RPE on every machine, but men and women used a similar percentage of their machine-specific peak VO2 at each RPE.

Heart rate was generally similar among the machines and between men and women at each RPE. The authors' point is calorie burn: more energy at the same RPE on a treadmill or ski simulator than on other devices.

Our reading for the base: the same perceived effort gave roughly the same heart rate on six machines while the absolute energy cost differed widely — the closest the base has to "keep the effort, not the pace or the watts" when an athlete changes machine.

The abstract does not say whether the percentage of machine-specific peak VO2 was the same across machines; it compares men with women on each machine.

A 2001 study; a later, smaller one outside the base (Edwards 2012, 10 men at RPE 15) found heart rate lower on a rower than on a treadmill, and REF-1435 found the same heart rate on a treadmill, elliptical and stepper at the same share of each device's peak workload.