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Analysis of velocity- and power-load relationships of the free-weight back-squat and hexagonal bar deadlift exercises

The aim of this study was to analyse the load-velocity and load-power relationships in the freeweight back-squat (BSQ) and hexagonal bar deadlift (HBD) exercises. Twenty-five (n = 25) resistance-trained men (age = 23.7 ± 2.8 years) performed a progressive load test at maximal intended velocity to determine their BSQ and HBD one-repetition maximum (1RM). Mean propulsive velocity (MPV) during the concentric phase of the lift was recorded through a  linear encoder. Load-velocity and load-power relationships were analysed by fitting linear regression and the second-order polynomial, respectively, to the data. Maximum strength (1RM), MPV (30–80% 1RM), and power output (30–90% 1RM) were higher for HBD compared to BSQ exercise (p < 0.05). A very strong relationship between MPV and relative intensity was found for both BSQ (R2 = 0.963) and HBD (R2 = 0.967) exercises. The load that maximizes power output (Pmax) was 64.6 ± 2.9% (BSQ) and 59.6 ± 1.1% (HBD) 1RM. There was a range of loads at which power output was not different than Pmax (BSQ: 40–80% 1RM; HBD: 50–70% 1RM). In conclusion, the load-velocity and load-power relationships might assist strength and conditioning coaches to monitor and prescribe exercise intensity in the BSQ and HBD exercises using the velocitybased training approach. CITATION: Gantois P, de Souza Fonseca F, Nakamura FY et al. Analysis of velocityand power-load relationships of the free-weight back-squat and hexagonal bar deadlift exercises. Biol Sport. 2023;40(1):201–208. Received: 2021-09-18; Reviewed: 2021-10-10; Re-submitted: 2021-12-27; Accepted: 2022-01-22; Published: 2022-02-18. further investigation of the entire load-velocity relationship in the most common resistance exercises employed in RT programmes to successfully implement the velocity-based approach. The back-squat (BSQ) and deadlift exercises and their variations are among the most common resistance exercises used to enhance the strength of knee extensors and flexor muscles [9]. Different exercise modes (Smith machine vs. free-weight, range of motion, and equipment design) produce distinct kinematic outputs and load-velocity relationships [10–13]. For example, previous studies showed that modifying the squatting depth (i.e. full vs. half) resulted in different biomechanical patterns, force development, and kinematic outputs [6, 10]. The load-velocity relationship in the Smith machine BSQ and traditional deadlift (i.e., straight bar) exercises has already been described [8, 10, 14–17]. However, reports of the load-velocity and load-power relationship in variations of the back-squat (i.e. free-weight) and traditional deadlift (i.e., hexagonal bar) exercises are limited. Despite the popularity of both free-weight BSQ and hexagonal deadlift (HBD) exercises among strength and conditioning coaches, Original Paper DOI: https://doi.org/10.5114/biolsport.2023.112966