RATINGS OF PERCEIVED EXERTION (RPE) AS AN INDEX OF AEROBIC ENDURANCE DURING LOCAL AND GENERAL EXERCISES

The main purpose of this study was to assess the correlations of RPE w ith indicators of endurance (critical power), exhaustion time and the electromyographic activity of a relevant muscle during general and loc al exercises. Eight healthy subjects participated in the study. During the first session, Maximal Aerobic Power (MAP) was measured by means of an incremental cycling exercise on a Monark ergorneter. At I-week i ntervals the participants performed a general or local exhausting exer cise, which consisted of a cycle exercise (60, 73, 86 or 100% MAP) and a knee extension exercise (lifting a load between 17.5 and 32.5 kg ev ery 3 s), respectively. The critical powers corresponding to cycling ( CPcycling) and knee extension (CPknee) were calculated from the slope of the linear relationship between exhaustion time (t(lim)) and work. Rate of perceived exertion, concerning the whole body (overall RPE [RP Eov]), RPE concerning the exercising muscles (muscular RPE [RPEmu]) an d exhaustion time were measured. During the last session, the integrat ed electromyogram of the right Vastus Lateralis (iEMG s(-1)) was measu red during short (20 s) cycling and knee extension non-exhausting exer cises, with the same electrode location, at the different power output s used during the exhausting exercises. The relationships between RPEm u at the fifth minute and log t(lim) and between iEMG% (percentage of the iEMG s(-1) corresponding to 100% MAP during cycling) and log t(lim ) were similar for the cycling and knee extension exercises. The mean Values of RPEmu at the fifth minute of exercise calculated for CPcycli ng and CPknee were almost equal (12.3 +/- 1.7 versus 12.2 +/- 0.9). Si milarly, the mean values of iEMG% corresponding to CPcycling and CPkne e were equal (78.44 versus 79.02%). These results suggest that RPEmu i s related to aerobic endurance and that the possibility of sustaining a high percentage of maximal aerobic power during a general exercise i s mainly related to local muscular factors.