The Accuracy of Prediction Equations for Estimating 1-RM Performance in the Bench Press, Squat, and Deadlift

Abstract

This study was done to determine the accuracy of 7 equations for predicting a 1-RM from repetitions to fatigue for the bench press, squat, and deadlift. Subjects, 67 untrained college students (40 M, 27 F) who were enrolled in weight training classes, participated in four 45-min practice sessions to learn proper lifting technique and determine the amount of weight to lift for the 1-RM test. All correlation coefficients between predicted and achieved 1-RM lifts were high (r > 0.95). For the bench press, however, the average differences between achieved and predicted weights were significantly different from zero in all but 2 equations. For the squat, the average difference was significantly different from zero in all but 1 equation. All equations significantly underestimated the deadlift despite high correlations.