September 2013; Vol. 2, No. 2: Pages 19-22

Lower body kinetics during the jump shrug: impact of load

Timothy J. Suchomel, George K. Beckham, and Glenn A. Wright

Abstract

Objectives: To examine the impact of load on lower body kinetics during the jump shrug. Design: Randomized, repeated measures design. Methods: Fourteen men performed randomized sets of the jump shrug at relative loads of 30%, 45%, 65%, and 80% of their one repetition maximum hang clean (1RM-HC). A number of variables were obtained through analysis of the force-time data, which included peak force, peak velocity, peak power, force at peak power, and velocity at peak power. A series of one-way repeated measures ANOVA were used to compare the differences in peak force, peak velocity, peak power, force at peak power, and velocity at peak power between each load. Results: Statistical differences in peak velocity, peak power, force at peak power, and velocity at peak power existed between loads (p<0.001), while peak force trended toward statistical significance (p=0.060). The greatest peak velocity, peak power, and velocity at peak power occurred at 30% 1RM-HC. In addition the greatest peak force and force at peak power occurred at loads of 65% and 80% 1RM-HC, respectively. Conclusions: Velocity is the greatest contributing factor to peak power production during the jump shrug. Practitioners should prescribe specific loading schemes for the jump shrug to provide optimal training stimuli to their athletes based on the training goal: specifically, loads of 65% 1RM-HC or higher, loads of approximately 30-45% 1RM-HC, and loads of 30% 1RM-HC should be prescribed for improvements in peak force and force at peak power, peak power, and velocity and velocity at peak power, respectively.

Received August 21, 2013; accepted September 25, 2013

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