A comparative kinematic analysis of the deadlift performed using the Olympic bar and the Troy-hex bar

摘要

The deadlift comprises eccentric and concentric phases of muscle activation, and is routinely used by sportsmen as the basis of strength and power training for the back and legs. One of the issues involved in performing the deadlift, is the strain it places on the lower spine. The deadlift is traditionally performed using the Olympic barbell. There is strong anecdotal evidence that the newly introduced Troy Hex bar reduces the strain on the lower back, and it is routinely used in America in preference to the Olympic barbell in training programmes. This has not however, been proven objectively. The purpose of the study was to examine the kinematic and electromyographical differences between deadlifts performed using the Olympic barbell and the Troy-Hex bar. With institutional ethical approval, six rugby union players with experience in performing deadlifts (mean¼3 years, s¼1.2) were recruited as participants. Each subject performed three deadlifts using the Olympic bar and three using the Troy-Hex bar. Three participants performed the deadlift with the Olympic bar first and three performed the deadlift with the Troy-Hex bar first. Participants were allowed 10 min rest between sets. The weight lifted was set at the subject’s individual six repetition maximum. Video data were obtained from a high definition camera from a lateral iewpoint. A kinematic analysis was undertaken to examine the displacement of the bar, the centre of mass of the subject, and the angles of the spine, hips and knees at key positions. Surface electromyography electrodes were fitted above the right erector spinae, and electrical activity was sampled at 500 Hz. The mean muscle activation for the ascent and descent phases was calculated, and compared. Erector spinae activation during the descent and ascent phases was found to be significantly less (P50.05) when using the Troy-Hex bar. Significant differences (P50.05) were also found between the angles of the trunk, hip, knee angles at key positions. Results indicate a more erect trunk position was maintained throughout the deadlift performed using the Troy-Hex bar, reflected in reduced erector spinae muscle activation during both the ascent and descent phase of the lift, suggesting a safer method of lifting. Serious consideration therefore needs to be given to the use of the Troy-Hex bar when performing deadlifts as part of strength and conditioning training programmes.