Validity of Different Velocity-Based Methods and Repetitions-to-Failure Equations for Predicting the 1 Repetition Maximum During 2 Upper-Body Pulling Exercises

This study aimed to compare the accuracy of different velocity-based methods and repetitions-to-failure equations for predicting the one-repetition maximum (i.e., maximum load that can be lifted once; 1RM) during two upper-body pulling exercises. Twenty-three men were tested in two sessions during the lat pulldown and seated cable row exercises. Each session consisted of an incremental loading test until reaching the 1RM followed by a set of repetitions-to-failure against the 80%1RM load. The 1RM was estimated from the individual load-velocity relationships modelled through four (~40, 55, 70, and 85%1RM; multiple-point method) or two loads (~40 and 85%1RM; two-point method). Mean velocity was recorded with a linear position transducer and a smartphone application. Therefore, four velocity-based methods were used as a result of combining the two devices and the two methods. Two repetitions-to-failure equations (Mayhew and Wathan) were also used to predict the 1RM from the load and number of repetitions completed. The absolute differences with respect to the actual 1RM were higher for the repetitions-to-failure equations than velocity-based methods during the seated cable row exercise (P=0.004), but not for the lat pulldown exercise (P=0.200). The repetitions-to-failure equations significantly underestimated the actual 1RM (P<0.05; range: -6.65 to -2.14 kg), while no systematic differences were observed for the velocity-based methods (range: -1.75 to 1.65 kg). All predicted 1RMs were highly correlated with the actual 1RM (r≥0.96). The velocity-based methods provide a more accurate estimate of the 1RM than the Mayhew and Wathan repetitions-to-failure equations during the lat pulldown and seated cable row exercises.