EFFECT OF INTERREPETITION REST ON POWER OUTPUT IN THE POWER CLEAN JUSTIN P. HARDEE, N. TRAVIS TRIPLETT,ALAN C. UTTER,KEVIN A. ZWETSLOOT, AND JEFFREY M. MCBRIDE Neuromuscular and Biomechanics Laboratory, Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, North Carolina ABSTRACT Hardee, JP, Triplett, NT, Utter, AC, Zwetsloot, KA, and Mcbride, JM. Effect of interrepetition rest on power output in the power clean. J Strength Cond Res 26(4): 883–889, 2012—The effect of interrepetition rest (IRR) periods on power output during performance of multiple sets of power cleans is unknown. It is possible that IRR periods may attenuate the decrease in power output commonly observed within multiple sets. This may be of benefit for maximizing improvements in power with training. This investigation involved 10 college-aged men with proficiency in weightlifting. The subjects performed 3 sets of 6 repetitions of power cleans at 80% of their 1 rep- etition maximum with 0 (P0), 20 (P20), or 40 seconds (P40) of IRR. Each protocol (P0, P20, P40) was performed in a ran- domized order on different days each separated by at least 72 hours. The subjects performed the power cleans while standing on a force plate with 2 linear position transducers attached to the bar. Peak power, force, and velocity were obtained for each repetition and set. Peak power significantly decreased by 15.7% during P0 in comparison with a decrease of 5.5% (R1: 4,303 6 567 W, R6: 4,055 6 582 W) during P20 and a decrease of 3.3% (R1: 4,549 6 659 W, R6: 4,363 6 476 W) during P40. Peak force significantly decreased by 7.3% (R1: 2,861 6 247 N, R6: 2,657 6 225 N) during P0 in comparison with a decrease of 2.7% (R1: 2,811 6 327 N, R6: 2,730 6 285 N) during P20 and an increase of 0.4% (R1: 2,861 6 323 N, R6: 2,862 6 280 N) during P40. Peak velocity significantly decreased by 10.2% (R1: 1.97 6 0.15 mÁs 21 , R6: 1.79 6 0.11 mÁs 21 ) during P0 in comparison with a decrease of 3.8% (R1: 1.89 6 0.13 mÁs 21 , R6: 1.82 6 0.12 mÁs 21 ) during P20 and a decrease of 1.7% (R1: 1.93 6 0.17 mÁs 21 , R6: 1.89 6 0.14 mÁs 21 ) during P40. The results demonstrate that IRR periods allow for the maintenance of power in the power clean during a multiple set exercise protocol and that this may have implications for improved training adaptations. KEY WORDS force, velocity, fatigue, weightlifting INTRODUCTION T he ability to generate power is one of the main determinants of performance in sports requiring high forces over a short time period (1,2,10,20,21). Several investigations have indicated that impro- vement in power and athletic performance may be influenced by using weightlifting movements such as the power clean during training (14,25). It has been suggested that fatigue may reduce the effectiveness of power development through decreases in movement velocity and manipulations to exercise technique (23). It is possible that interrepetition rest (IRR) periods may attenuate these unwanted con- sequences of fatigue during training. It is clear that muscular power output is reduced with fatigue (5,16), especially during high-intensity activities that require high rates of muscular contraction (24). Reductions in power output result from a decline in both force and velocity (8,9). Power, force, and velocity have been shown to decrease with each repetition during resistance exercise (15,19). Izquierdo et al. (15) demonstrated significant decreases in repetition velocity at one-third (13%) and one-half (8%) of repetitions to failure in the bench press and squat exercises, respectively. Lawton et al. (19) demonstrated a near-linear decrease in power output during a 6 repetition maximum (RM) bench press exercise. Significant decreases in power output were found with each repetition (7.6 6 9.3%, 17.9 6 8.1%, 30.3 6 9.4%, 41.9 6 11.6%, and 52.9 6 11.5%, respectively) (19). Duffey and Challis (7) also demonstrated significant decreases in mean and peak velocity during repetitions to failure in the bench press. Drinkwater et al. (6) also found significant decreases in mean and peak power output during the bench press over multiple sets and repetitions. These studies give an insight into the effect of fatigue on power production within single-set configurations; however, these are not common to muscular power training programs that involve multiple set protocols. Conflict of interest: The authors recognize no conflicts of interest. The results of this study do not constitute endorsement by the National Strength and Conditioning Association. Address correspondence to Jeffrey M. McBride, mcbridejm@appstate. edu. 26(4)/883–889 Journal of Strength and Conditioning Research Ó 2012 National Strength and Conditioning Association VOLUME 26 | NUMBER 4 | APRIL 2012 | 883 Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.