484 International Journal of Sports Physiology and Performance, 2010, 5, 484-496 © 2010 Human Kinetics, Inc. Relationship Between Relative Net Vertical Impulse and Jump Height in Jump Squats Performed to Various Squat Depths and With Various Loads Jeffrey M. McBride, Tyler J. Kirby, Tracie L. Haines, and Jared Skinner Purpose: The purpose of the current investigation was to determine the relation- ship between relative net vertical impulse (net vertical impulse (VI)) and jump height in the jump squat (JS) going to different squat depths and utilizing various loads. Methods: Ten males with two years of jumping experience participated in this investigation (Age: 21.8 ± 1.9 y; Height: 176.9 ± 5.2 cm; Body Mass: 79.0 ± 7.1 kg, 1RM: 131.8 ± 29.5 kg, 1RM/BM: 1.66 ± 0.27). Subjects performed a series of static jumps (SJS) and countermovement jumps (CMJJS) with various loads (Body Mass, 20% of 1RM, 40% of 1RM) in a randomized fashion to a depth of 0.15, 0.30, 0.45, 0.60, and 0.75 m and a self-selected depth. During the concentric phase of each JS, peak force (PF), peak power (PP), jump height (JH) and relative VI were recorded and analyzed. Results: Increasing squat depth cor- responded to a decrease in PF and an increase in JH, relative VI for both SJS and CMJJS during all loads. Across all squat depths and loading conditions relative VI was statistically signifcantly correlated to JH in the SJS (r = .8956, P < .0001, power = 1.000) and CMJJS (r = .6007, P < .0001, power = 1.000). Across all squat depths and loading conditions PF was statistically nonsignifcantly correlated to JH in the SJS (r = –0.1010, P = .2095, power = 0.2401) and CMJJS (r = –0.0594, P = .4527, power = 0.1131). Across all squat depths and loading conditions peak power (PP) was signifcantly correlated with JH during both the SJS (r = .6605, P < .0001, power = 1.000) and the CMJJS (r = .6631, P < .0001, power = 1.000). PP was statistically signifcantly higher at BM in comparison with 20% of 1RM and 40% of 1RM in the SJS and CMJJS across all squat depths. Conclusions: Results indicate that relative VI and PP can be used to predict JS performance, regard- less of squat depth and loading condition. However, relative VI may be the best predictor of JS performance with PF being the worst predictor of JS performance. Keywords: static, countermovement, impulse, power Jeffrey M. McBride, Tyler J. Kirby, Tracie L. Haines, and Jared Skinner are with the Neuromuscular Labo- ratory, Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, NC.