A novel scale to assess resistance-exercise effort

J Sports Sci. 2012;30(13):1405-13. doi: 10.1080/02640414.2012.710757. Epub 2012 Aug 9.


In this study, we examined the validity of a novel subjective scale for assessing resistance-exercise effort. Seventeen male bodybuilders performed five sets of 10 repetitions at 70% of one-repetition maximum, for the bench press and squat. At the completion of each set, participants quantified their effort via the rating of perceived exertion (RPE) and novel estimated-repetitions-to-failure scales, and continued repetitions to volitional exhaustion to determine actual-repetitions-to-failure. There were high correlations between estimated- and actual-repetitions-to-failure across sets for the bench press and squat (r ≥ 0.93; P < 0.05). During sets 3, 4, and 5, estimated-repetitions-to-failure predicted the number of repetitions to failure for the bench press and squat, as indicated by smaller effect sizes for differences (ES = 0.37-0.0). The estimated-repetitions-to-failure scale was reliable as indicated by high intraclass correlation coefficients (≥0.92) and narrow 95% limits of agreement (≤0.63 repetitions) for both the bench press and squat. Despite high correlations between RPE and actual-repetitions-to-failure (P < 0.05), RPE at volitional fatigue was less than maximal for both exercises. Our results suggest that the estimated-repetitions-to-failure scale is valid for predicting onset of muscular failure, and can be used for the assessment and prescription of resistance exercise.

Publication types

  • Validation Study

MeSH terms

  • Adult
  • Energy Metabolism*
  • Exercise
  • Humans
  • Male
  • Muscle Fatigue*
  • Muscle, Skeletal
  • Perception*
  • Physical Endurance*
  • Physical Exertion*
  • Reproducibility of Results
  • Resistance Training*
  • Weight Lifting*