title: A novel scale to assess resistance-exercise effort.
abstract: 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.
authors.affiliation: Discipline of Exercise and Sports Science, University of Sydney, Lidcombe, New South Wales, Australia. daniel.hackett@sydney.edu.au
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hackett
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Johnson
authors.forename: Mark
authors.initials: M
authors.lastname: Halaki
authors.forename: Chin-Moi
authors.initials: CM
authors.lastname: Chow
mesh_terms: D000328:Adult; D004734:Energy Metabolism; D015444:Exercise; D006801:Humans; D008297:Male; D018763:Muscle Fatigue; D018482:Muscle, Skeletal; D010465:Perception; D010807:Physical Endurance; D005082:Physical Exertion; D015203:Reproducibility of Results; D055070:Resistance Training; D014891:Weight Lifting