Perceived exertion scales attest to both intensity and exercise duration

The present purpose was to study the relationships between perceived exertion (RPE, ETL) and exercise duration for all-out runs eliciting v(V) over dot O-2 max.12 endurance-trained men performed three exhausting exercises on an indoor track. The first test was an incremental exercise to measure their maximal oxygen uptake ((V) over dot O-2 max), the velocity associated with (V) over dot O-2 max (v(V) over dot O-2 max), the velocity of the lactate concentration threshold (vLT) and the velocity delta 50 (vDelta50: the velocity halfway between v(V) over dot O-2 max and vLT). The second and third tests were a constant load all-out run at v(V) over dot O-2 max and vDelta50 to measure the time to exhaustion at these intensities (tlim v(V) over dot O-2, max and tlimvDelta50, respectively). vDelta50 corresponded to 90.1 +/- 2.5% v 10, max; dim v(V) over dot O-2 max and tlimvDelta50 were equal to 286 +/- 71 sec. and 547 +/- 157 sec., respectively. For a same given relative time (%tlim), athletes perceived exercise as harder and felt that they could endure less for v(V) over dot O-2 max than vDelta50, When subjects began to perceive exercise as "hard" (RPE = 15), they had run for only 36.4 +/- 26.8%tlim at v(V) over dot O-2 max, whereas they had run for 46.1 +/- 15.7 %tlim at vDelta50. These results indicate that RPE and ETL scales were a combined subjective estimation of both intensity and exercise duration for all-out runs at 90 and 100% v(V) over dot O-2 max. Therefore, this scale could be used to assess duration as well as intensity of exercise for the practical application in sport. Moreover, it could be suggested that exercise duration can be prescribed as a function of perceived exertion for healthy normal people. Consequently, perceived exertion could be an important tool to individualize the prescription of a training program.