THE ACUTE EFFECTS OF AN ASCENDING SQUAT PROTOCOL ON PERFORMANCE DURING HORIZONTAL PLYOMETRIC JUMPS RYAN M. RUBEN,MICHELLE A. MOLINARI,CHARLOTTE A. BIBBEE,MATT A. CHILDRESS, MEGAN S. HARMAN,KYLE P. REED, AND G. GREGORY HAFF Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia ABSTRACT Ruben, RM, Molinari, MA, Bibbee, CA, Childress, MA, Harman, MS, Reed, KP, and Haff, GG. The acute effects of an ascending squat protocol on performance during horizontal plyometric jumps. J Strength Cond Res 24(2): 358–369, 2010—The purpose of the present investigation was to examine the effects of a strength-power potentiation complex that involved perform- ing a horizontal plyometric activity 5 minutes after the com- pletion of an ascending back squat protocol. Twelve men who could back squat a minimum of 1.5 time body mass participated in a familiarization session and 2 randomly assigned testing sessions each separated by approximately 1 week. In the control session, the subject rested for 5 minutes and then performed the horizontal plyometric tests. In the potentiation session (POT), the subjects performed an ascending back squat protocol that consisted of 5 repetitions at 30% of 1 repetition maximum (1RM), 3 repetitions at 70% 1RM, and 3 repetitions at 90% 1RM. Five minutes after completing the ascending back squat protocol, the subjects undertook the horizontal plyometric test, which consisted of jumping over 5 hurdles that were separated by 45.7 cm and were set to a height of 65.2 6 4.0 cm. An accelerometer was used to assess peak power output (PP), velocity (PV), and force (PF) across the 5 jumps. The average PF generated across the 5 hurdles was significantly higher in the POT session (p = 0.01, d = 0.45). In addition, the maximum PP output (p = 0.05, d = 1.12) and PF (p = 0.004, d = 0.61) were higher in the POT trials. Individuals who were able to back squat approximately 2.0 6 0.1 times body mass exhibited a greater percent potentiation for average PP output (p = 0.001, h 2 = 0.68) and average PV (p = 0.02, h 2 = 0.61). The present data suggest only very strong individuals (back squat $ 2.0 3 body mass) exhibit a potentiation effect in a horizontal plyometric activity after performing an ascending back squat protocol. KEY WORDS power, complex pairs, accelerometers, potentiation INTRODUCTION I n the field of strength and conditioning, the use of strength-power potentiating complexes (SPPC) or complex pairs (20) has recently received a large amount of attention, which has resulted in an increased amount of research examining the effectiveness of this practice (10,17,34,39). Generally, a SPPC involves the performance of a high-force (17) or high-power movement (30) that is used to potentiate a subsequent high-power or high-velocity movement, such as a plyometric activity. For example, a heavy-loaded back squat has been used to potentiate a subsequent vertical jump performance (8,27). In addition, a series of ascending back squats has been reported to result in a potentiation of subsequent vertical jump (13) and sprinting performance (27,38). Although the use of a SPPC is not a new concept (36), recent investigation suggests that this practice can result in an acute increase in the high- power or velocity portion of the SPPC (10,27,38,39). Stone et al. (34) suggest that the fitness-fatigue paradigm serves as the theoretical basis for the use of the SPPC. As an acute performance factor, this theory suggests that the potentiation inducing exercises performed results in an elevation in both fitness and fatigue. The volume and intensity of these activities will modulate the magnitude of the fatigue that is generated, which will affect preparedness or the athlete’s ability to express the fitness aftereffects that are accumulated in response to this activity. Because fatigue dissipates at a faster rate than fitness, it is possible to acutely express the fitness aftereffects in the high-power or velocity portion of the SPPC by modulating the time that elapses between the 2 portions of the SPPC. A large amount of research has been performed to determine the optimal window of time necessary between the 2 portions of a SPPC (2,4–7,10–13,26,39). Collectively, these studies suggest that the duration of recovery between Address correspondence to G. Gregory Haff, ghaff@hsc.wvu.edu. 24(2)/358–369 Journal of Strength and Conditioning Research Ó 2010 National Strength and Conditioning Association 358 Journal of Strength and Conditioning Research the TM