A three-dimensional biomechanical analysis of sumo and conventional style deadlifts RAFAEL F. ESCAMILLA, ANTHONY C. FRANCISCO, GLENN S. FLEISIG, STEVEN W. BARRENTINE, CHRISTIAN M. WELCH, ANDREW V. KAYES, KEVIN P. SPEER, and JAMES R. ANDREWS Michael W. Krzyzewski Human Performance Laboratory, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710; American Sports Medicine Institute, Birmingham, AL 35205; and Human Performance Technologies, Inc., Jupiter, FL 33477 ABSTRACT ESCAMILLA, R. F., A. C. FRANCISCO, G. S. FLEISIG, S. W. BARRENTINE, C. M. WELCH, A. V. KAYES, K. P. SPEER, and J. R. ANDREWS. A three-dimensional biomechanical analysis of sumo and conventional style deadlifts. Med. Sci. Sports Exerc., Vol. 32, No. 7, pp. 1265–1275, 2000. Purpose: Strength athletes often employ the deadlift in their training or rehabilitation regimens. The purpose of this study was to quantify kinematic and kinetic parameters by employing a three-dimensional analysis during sumo and conventional style deadlifts. Methods: Two 60-Hz video cameras recorded 12 sumo and 12 conventional style lifters during a national powerlifting championship. Parameters were quantified at barbell liftoff (LO), at the instant the barbell passed the knees (KP), and at lift completion. Unpaired t-tests (P , 0.05) were used to compare all parameters. Results: At LO and KP, thigh position was 11–16° more horizontal for the sumo group, whereas the knees and hips extended approximately 12° more for the conventional group. The sumo group had 5–10° greater vertical trunk and thigh positions, employed a wider stance (70 6 11 cm vs 32 6 8 cm), turned their feet out more (42 6 8° vs 14 6 6°), and gripped the bar with their hands closer together (47 6 4 cm vs 55 6 10 cm). Vertical bar distance, mechanical work, and predicted energy expenditure were approximately 25– 40% greater in the conventional group. Hip extensor, knee extensor, and ankle dorsiflexor moments were generated for the sumo group, whereas hip extensor, knee extensor, knee flexor, and ankle plantar flexor moments were generated for the conventional group. Ankle and knee moments and moment arms were significantly different between the sumo and conventional groups, whereas hip moments and moments arms did not show any significantly differences. Three-dimensional calculations were more accurate and significantly different than two-dimensional calcu- lations, especially for the sumo deadlift. Conclusions: Biomechanical differences between sumo and conventional deadlifts result from technique variations between these exercises. Understanding these differences will aid the strength coach or rehabilitation specialist in determining which deadlift style an athlete or patient should employ. Key Words: POWERLIFTING, WEIGHTLIFTING, JOINT MOMENTS, JOINT MOMENT ARMS, JOINT ANGLES, SEGMENT ANGLES, KINEMATICS, KINETICS, MECHANICAL WORK T he deadlift, which measures overall body strength, is the last of three lifts in powerlifting competition. The starting position for the deadlift is with the lifter in a squat position, arms straight and pointing down, and an alternating hand grip used to hold a bar positioned in front of the lifter’s feet. According to the American Drug Free Powerlifting Association (ADFPA) rules at the time of this study, the barbell is lifted upward in a continuous motion until the lifter is standing erect with knees locked and the shoulders thrust back. Causes for disqualification included failure to wait for the referee’s “down” signal at the com- pletion of the lift, any stopping or downward movement of the bar once the bar leaves the lifting platform, failure to stand erect with locked knees and shoulders thrust back, and any “hitching,” bouncing, or resting of the bar against the thighs during the lift. All deadlift trials analyzed in the current study were in accordance with these rules. Strength athletes, such as American football players, of- ten employ the barbell deadlift in their training or rehabil- itation regimens. These athletes use the deadlift to enhance hip, thigh, and back strength. The deadlift is performed using either a conventional or sumo style. The primary differences between these two styles are that the feet are positioned further apart and turned out in the sumo style, and the arms are positioned inside the knees for the sumo style and outside the knees for the conventional style. Stance width, foot angle, and hand width differences between these two styles have not yet been quantified. Although both deadlift styles are used in training, the efficacy of one style over another is unclear. Because the deadlift is considered a closed kinetic chain exercise (23), it can also be employed in knee rehabilitation 0195-9131/00/3207-1265/0 MEDICINE & SCIENCE IN SPORTS & EXERCISE ® Copyright © 2000 by the American College of Sports Medicine Submitted for publication April 1999. Accepted for publication October 1999. 1265