COMPARISON OF BLOOD LACTATE CONCENTRATION AND RATINGS OF PERCEIVED EXERTION DURING TWO STANDARD TREADMILL PROTOCOLS 422

Abstract

The purpose of this study was to determine if previously observed differences in ratings of perceived exertion (RPE) at the same intensities during two graded exercise tests (GXT) were the result of differences in blood lactate concentration (BLC). Eleven healthy males (25.3 ± 5.3 yrs) were maximally tested using two standard treadmill protocols (Bruce & Balke 3.0 mph/2.5% each 2 min). Subjects were randomly assigned to one GXT and completed the second test approximately 48 hours later. Both GXTs were completed within one week. RPEs were recorded at the end of each 2 minute stage of the Balke and twice per stage during the Bruce protocol. BLCs were collected each minute during both protocols. Mean RPE and BLC data at different relative sub-maximal exercise intensities are presented as Mean ± S.D.Table Results: RPE data were first analyzed using two-way ANOVA(protocol x intensity), and a significant interaction was observed with RPEs being higher at each intensity during the Balke protocol. The addition of the BLC at each relative exercise intensity as a covariate in the model suggested that BLC accounted for some of the protocol differences in RPE, particularly at the higher intensities. Conclusion: Therefore, differences in RPEs between standard GXT protocols reported in previous studies were due, in part, to differences in BLC.