THE EFFECT OF LOAD ON THE KINEMATICS OF THE SUMO DEADLIFT IN COMPETITIVE POWERLIFTERS

A. Campitelli, A. Coehlo, J.McNeal Eastern Washington University, Cheney, WA It has been shown in fundamental resistance training movements, such as the squat and bench press, that varying the load lifted also significantly changes the kinematics of the movement. Variable kinematics present a safety and specificity concern for lifters and coaches alike. The effect of load, however, has never been examined in the sumo deadlift exercise, an exercise employed extensively by both powerlifters and athletes. PURPOSE: To determine the effect of loading on the kinematics of the lower limbs and trunk during the sumo deadlift in powerlifters. METHODS: Experienced, competitive, male powerlifters (n = 10) reported to the lab for an initial session where their 1-repetition maximum (1RM) lifts were determined in accordance with powerlifting rules. In a second session one week later, two 60-Hz video cameras recorded submaximal lifts by the participants under four loading conditions (30, 50, 70, and 90% 1RM). Angles were quantified at liftoff (LO), at the instant the barbell passed the knees (KP), and at lift completion for the hip, knee and ankle joint, and the angle of trunk inclination. One-way repeated measures ANOVA with post-hoc pairwise comparisons (α = 0.05) were used to find differences caused by load at each joint. RESULTS: At LO, significant differences were found for the knee joint angle (118.9±6.8° at 30% vs. 132.3±6.5° at 90%, p \u3c 0.001), ankle joint angle (76.3±6.0° at 30% vs. 80.5±6.2° at 90%, p = 0.003), and the angle of trunk inclination (47.4±6.0° at 30% vs. 55.0±5.3° at 90%, p = 0.001) due to load. Pairwise comparisons revealed significant differences between all loads at all joint angles at LO (p\u3c 0.05). At KP, significant differences were found for the ankle joint angle (85.9±6.1° at 30% vs. 89.2±5.6° at 90%, p = 0.033) due to load. CONCLUSIONS: Sumo deadlift kinematics seem to be affected by the load being lifted, generally tending to manifest as greater ankle and knee angles and a more inclined (greater deflection from vertical) trunk as the load increased, particularly during LO. Utilizing a sample of only male competitive powerlifters make these results difficult to generalize, future research should examine the effect of load on sumo deadlift kinematics on a broader sample which is more reflective of the population who may utilize this exercise in training