title: A biomechanical analysis of straight and hexagonal barbell deadlifts using submaximal loads.
abstract: The purpose of the investigation was to compare the kinematics and kinetics of the deadlift performed with 2 distinct barbells across a range of submaximal loads. Nineteen male powerlifters performed the deadlift with a conventional straight barbell and a hexagonal barbell that allowed the lifter to stand within its frame. Subjects performed trials at maximum speed with loads of 10, 20, 30, 40, 50, 60, 70, and 80% of their predetermined 1-repetition maximum (1RM). Inverse dynamics and spatial tracking of the external resistance were used to quantify kinematic and kinetic variables. Subjects were able to lift a heavier 1RM load in the hexagonal barbell deadlift (HBD) than the straight barbell deadlift (SBD) (265 ± 41 kg vs. 245 ± 39 kg, p < 0.05). The design of the hexagonal barbell significantly altered the resistance moment at the joints analyzed (p < 0.05), resulting in lower peak moments at the lumbar spine, hip, and ankle (p < 0.05) and an increased peak moment at the knee (p < 0.05). Maximum peak power values of 4,388 ± 713 and 4,872 ± 636 W were obtained for the SBD and HBD, respectively (p < 0.05). Across the submaximal loads, significantly greater peak force, peak velocity and peak power values were produced during the HBD compared to during the SBD (p < 0.05). The results demonstrate that the choice of barbell used to perform the deadlift has a significant effect on a range of kinematic and kinetic variables. The enhanced mechanical stimulus obtained with the hexagonal barbell suggests that in general the HBD is a more effective exercise than the SBD.
authors.affiliation: School of Health Sciences, Robert Gordon University, Aberdeen, United Kingdom. p.swinton@rgu.ac.uk
authors.forename: Paul A
authors.initials: PA
authors.lastname: Swinton
authors.forename: Arthur
authors.initials: A
authors.lastname: Stewart
authors.forename: Ioannis
authors.initials: I
authors.lastname: Agouris
authors.forename: Justin W L
authors.initials: JW
authors.lastname: Keogh
authors.forename: Ray
authors.initials: R
authors.lastname: Lloyd
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007700:Kinetics; D007719:Knee Joint / Q000502:physiology; D008159:Lumbar Vertebrae; D008297:Male; D011187:Posture; D055070:Resistance Training / Q000295:instrumentation*; D013131:Spine / Q000502:physiology; D019876:Sports Equipment; D014891:Weight Lifting / Q000502:physiology*; D055815:Young Adult