Kinematic and kinetic analysis of maximal velocity deadlifts performed with and without the inclusion of chain resistance.
Swinton, Paul Alan
Stewart, Arthur D.
Keogh, Justin W. L.
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SWINTON, P. A., STEWART, A., KEOGH, J. W. L., AGOURIS, I., and LLOYD, R., 2011. Kinematic and kinetic analysis of maximal velocity deadlifts performed with and without the inclusion of chain resistance. Journal of Strength and Conditioning Research, 25 (11), pp. 3163-3174.
The purpose of this study was to investigate whether the deadlift could be effectively incorporated with explosive resistance training (ERT), and to investigate whether the inclusion of chains enhanced the suitability of the deadlift for ERT. Twenty three resistance trained athletes performed the deadlift with 30, 50 and 70% 1RM loads at submaximal velocity, maximal velocity, and maximal velocity with the inclusion of two chain loads equal to 20 or 40% of the subjects 1RM. All trials were performed on force platforms with markers attached to the barbell to calculate velocity and acceleration using a motion capture system. Significant increases in force, velocity, power, rate of force development and length of the acceleration phase (p < 0.05) were obtained when repetition velocity increased from submaximal to maximal. During maximal velocity repetitions with a constant resistance the mean length of the acceleration phase ranged from 73.2 (± 7.2%) to 84.9 (± 12.2%) of the overall movement. Compared to using a constant resistance the inclusion of chains enabled greater force to be maintained to the end of the concentric action and significantly increased peak force and impulse (p < 0.05), whilst concurrently decreasing velocity, power and rate of force development (p < 0.05). The effects of chains were influenced by the magnitude of the chain and barbell resistance, with greater increases and decreases in mechanical variables obtained when heavier chain and barbell loads were used. The results of the investigation suggest that the deadlift can be incorporated effectively in ERT programs. Coaches and athletes should be aware that the inclusion of heavy chains may have both positive and negative effects on kinematics and kinetics of an exercise.