OPTIMAL LOADING for FORCE PRODUCTION in the STRAIGHT BAR DEADLIFT: FORCE-TIME CHARACTERISTICS in STRENGTH-TRAINED ADULTS

This study sought to identify whether there is an optimum load in relation to peak force development and rate of force development (RFD) in the straight bar deadlift and to examine whether baseline strength levels influence this optimum load. Twelve strength-trained men (mean age ± SD; 25.1 ± 5.4 years) performed 3 deadlift repetitions at loads of 10% intervals of 20-90% of their predetermined individual 1 repetition maximum (1RM). Peak vertical force (PF_z) and RFD were determined from each repetition. The repetition at each percentage of 1RM that produced the greatest PF_z was used for analysis. All data were collected on an AMTI force platform. Repeated-measures analysis of variance indicated significant differences in PF_z across loads of 20-90% 1RM (p = 0.001) with a linear increase in PF_z with increasing % of 1RM. The highest PF_z occurred at 90% of 1RM. For RFD, there was a significant main effect for load (p = 0.018) where instantaneous RFD was significantly higher at 80 and 90% 1RM compared with 20% 1RM. When analyses were re-run using baseline strength as a covariate, the results did not change, indicating that baseline strength did not influence the PF_z or RFD output. These results suggest that there is no significant difference in RFD between adjacent loads, but that peak force production was greatest at 90% 1RM in the straight bar deadlift.