The effect of strength level on the validity and reliability of the load-velocity relationship predicted 1RM in the deadlift and military press

The aim of this study was to examine the validity and reliability of individualised load-velocity predicted 1RMs in the deadlift and military press, and to establish whether the strength levels of the subjects affected the accuracy of these equations. A secondary aim was to assess differences in the load velocity profile of the deadlift and military press. 25 males participated in the study (age = 29.8 ± 11.1 years; body mass = 83.75 ± 9.96kg; height = 180.44 ± 5.43cm; relative deadlift 1RM: 1.97 ± 0.32; relative military press 1RM: 0.74 ± 0.16). They were divided into strong and weak groups for each lift, with the threshold for inclusion in the strong group was set at ≥2.0 kg/kg for the deadlift, and ≥0.75 kg/kg for the military press. Subjects completed 3 testing sessions each, one baseline testing session (for anthropometric measurements, baseline 1RM measurements, and familiarisation) and two testing sessions where their load-velocity profiles were calculated in the deadlift and military press. The results found that (1) though all groups had a strong correlation between predicted and actual 1RM (r = 0.94) there was a significant difference between the accuracy for strong and weak groups, with strongers’ predictions being more accurate (r = 0.98 vs. r = 0.91; ES= 0.68 20 ), (2) the load velocity profile of the deadlift differed significantly between exercises at 40, 50, and 70 % of 1RM (p ≤ 0.05) with military press mean velocity being higher at these loads, and (3) though mean concentric velocity does not provide a perfect estimate of 1RM (MAPE = 5-8 %) velocity at submaximal loads are highly reliable in both strong and weak subjects in the deadlift and military press (ICC = ≥ 0.90). These results indicate that load velocity profiling should be specific to the subject strength level and exercise being used, and that velocities at submaximal loads are highly reliable across strength levels and exercises.