Put a Hex on your Deadlifts

Barbell rack at Quads Gym, Chicago.

The deadlift is one of the most important core exercises for strength and power training, and when performed with proper form and heavy loads, it will engage all the major muscle groups of the body. An article in the NSCA's Journal of Strength and Conditioning Research compares the biomechanic differences between the Straight Barbell Deadlift and the Hexagonal Barbell Deadlift. The results of the study by Paul A. Swinton and colleagues are very interesting, if your gym has a hexagonal barbell, you may want to add it to your routine.

The study involved 19 male powerlifters recruited from the Scottish Powerlifting Association. Subjects performed both 1RM lifts and submaximal lifts. Markers were placed at 12 different points on the lifters bodies, as well as on the ends of the barbells, this allowed for three dimensional tracking of the markers during the deadlifts.

Kinematics

During the SBD, the load is in front of the lifter, even when the bar is held as close to the body as possible. During the HBD, the lifter is within the bar and the axis of the load is aligned with coronal axis of the body.

Because the lifter is standing in line with the load during the HBD, the moment arms at each joint are significantly reduced. This means less shear force on the joints and greater muscular efficiency. Of particular interest is the reduction of the moment arm in the lumbar spine region, reducing disc pressure. The HBD also results in reduced lateral movements of the load over the course of the concentric action; the straighter the path of action, the more efficient the lift.

Kinetics

While force exerted during the HBD was only marginally greater than the SBD, velocities increased significantly at loads greater than 40% of the subjects 1RM. This means that power exerted during the HBD was significantly higher than that of the SBD. In addition, greater loads were able to be lifted with lower risk of injury.

Application

Choosing which barbell to use can thus be made based on desired muscle recruitment and joint activation. The SBD emphasizes engagement of the musculature of the lower back and hips, while the HBD emphasized engagement of the musculature of the hips and knees. The HBD may be used for lifters that are new to deadlifts, or that have had back problems in the past. Additionally, the HBD may be preferred for lifters seeking to develop power at higher loads.

Reference

A Biomechanical Analysis of Straight and Hexagonal Barbells Using Submaximal Loads. Swinton, Paul A., et al. The Journal of Strength & Conditioning Research. July 2011 vol. 25, no 7. (pp 2001-2009).