Validity and Reliability of a 3-Point Load-Velocity Profile for Predicting Hex Bar Deadlift 1 Repetition Maximum

ABSTRACT: Stevens, LJ, Carey, DL, Gastin, PB, and James, LP. Validity and reliability of a 3-point load-velocity profile for predicting hex bar deadlift 1 repetition maximum. J Strength Cond Res XX(X): 000-000, 2026-This study assessed the between-session reliability of load-velocity-derived parameters in the hex bar deadlift using a 3-point method and velocity-based load prescription and determined the validity of a predictive 1RM model based on these parameters relative to actual 1RM testing. Nineteen resistance-trained subjects completed 2 testing sessions consisting of a traditional 1RM test and a submaximal 3-load load-velocity assessment using the hex bar deadlift. Between-session reliability of measures derived from the load-velocity profile and 1RM testing were evaluated using coefficient of variation (CV) and intraclass correlation coefficient (ICC). A linear mixed-effects model was used to predict 1RM from theoretical maximal load (L0) and theoretical maximum velocity (V0) derived from individual load-velocity profiles. Bland-Altman plots with 95% limits of agreement were used to assess the level of agreement between methods. Between sessions, L0 showed excellent reliability (CV = 5.2%, ICC = 0.97), while V0 was generally less reliable (CV = 6.0%, ICC = 0.70). The predictive model explained nearly all variance in actual 1RM (marginal R2 = 0.975), with both L0 and V0 contributing significantly (p < 0.05). Predicted 1RM values were highly similar to actual 1RM values on average; however, the limits of agreement (±15.7 kg) suggest that the 2 methods are not directly interchangeable. Overall, the methodology used in this study provides a feasible alternative for assessing maximal strength, offering a less fatiguing and efficient option for athlete monitoring. However, due to individual variability, predicted 1RM values should not be used interchangeably with direct 1RM testing.