The validity of submaximal ratings of perceived exertion to predict one repetition maximum

The one repetition maximum (1-rm) test is commonly used toassess strength. however, direct assessments of 1-rm are timeconsuming and unsafe for novice lifters. whilst various equationsexist to predict 1-rm, there is limited research on thevalidity of these equations. the purpose of this study was toassess the validity of using sub-maximal ratings of perceivedexertion (rpe) to predict 1-rm in young adults, using the borg6-20 rpe scale. twenty healthy participants (ten male (mean ±sd, 20.8 ± 0.6 y, 75.7 ± 9.3 kg, 1.8 ± 0.07 m) and ten female(20.3 ± 0.7 y, 68.4 ± 10.0 kg, 1.68 ± 0.03 m)) completed twotrials involving resistance exercises for both the upper and lowerbody. in the first trial the 1-rm for the bilateral biceps curl (bc)and the bilateral knee extension (ke) were determined for eachparticipant. in the second trial, participants performed blindedrepetitions which were equivalent to 20, 40 and 60 % of 1-rmfor both exercises. the rpe was recorded immediately after tworepetitions had been completed at each intensity. the order ofintensity of the repetitions was randomly assigned with participantswearing blindfolds to exclude the possibility of predeterminedjudgments about load and rpe. individual rperecorded at each intensity was subjected to linear regressionanalysis and the line of best fit was extrapolated to rpe 20 topredict 1-rm in both exercises. there was no significant difference(p > 0.05) between the 1-rm predicted from rpe 20 andmeasured 1-rm for both exercises for the men and women.measured and predicted values for men were 46.0 ± 4.6 and45.2 ± 6.1 kg for biceps curl, and 46.3 ± 3.8 and 43.0 ± 7.1 kgfor knee extension, respectively. measured and predicted valuesfor women were 18.6 ± 5.7 and 19.3 ± 5.6 kg for biceps curl,and 25.5 ± 9.6 and 27.2 ± 12.6 kg for knee extension, respectively.pearson product-moment correlation coefficients betweenactual and predicted 1-rm for the bc and ke were 0.97and 0.92, respectively. these results provide evidence thatsubmaximal ratings of perceived exertion can be used to providereasonably accurate estimates of 1-rm in young and active menand women.