Sumo Deadlift vs Conventional Deadlift: A Biomechanical Analysis
Introduction
The deadlift is a multi joint movement that has a lot of clinical benefits, such as increasing bone mineral density and increasing functional strength. It also has benefits of performance enhancement, including improving sprinting speed, muscular hypertrophy, and core musculature activation (Del Vecchio, Daewoud, & Green, 2018). In the sport of powerlifting, the performance of the sport directly involves performing a deadlift. In a powerlifting meet, the goals of each competitor are to move as much weight as possible through a range of motion that is considered a complete lift, and to total the most weight between the squat, bench, and deadlift. Based on the USAPL statistics between 2012 and 2016, the deadlift is the biggest contributor to the total amount of weight lifted (Ball & Weidman, 2018). This makes optimizing the performance of the deadlift a key variable to being successful in a powerlifting meet.
Both sumo and conventional deadlifts are legal in USAPL sanctioned powerlifting meets. Both variations involve picking the barbell off the floor and ending in a lockout position. According to the USAPL rules, the lockout position of a legal deadlift involves full extension of the knees and hips, as well as complete scapular retraction . A sumo deadlift involves a wider stance, whereas a conventional set up is a closer stance. A wider stance would mean the barbell would have to travel less range of motion for lockout, theoretically allowing the athlete to move more weight. However, there is speculation that a conventional deadlift is biomechanically similar to a squat, which would theoretically allow improved performance in the squat. Regardless, there is still a significant difference in the mechanics of a conventional deadlift and squat at near maximal loads (Hales, Johnson, & Johnson, 2009).
Biomechanical Considerations
Linear Kinematics
Three of the more important linear kinetic variables involving the performance of the deadlift is vertical displacement and barbell velocity and acceleration. The displacement on the bar on both variations of the deadlift moves in the vertical direction. Conventional deadlifters have a wider grip on the barbell than those performing sumo, which causes the displacement of the bar to be greater during the conventional set up. Due to the amount of load that could be expected on a deadlift, the movement is typically slow. 24 powerlifters were observed with two 60hz cameras at a national powerlifting championship, 12 of them were performing conventional deadlifts and the other 12 had a sumo style setup. It was observed that the conventional deadlift had a significantly higher peak velocity than sumo. It should also be noted it took the conventional style lifters less time to reach peak velocity, therefore it can be concluded that the conventional style also has greater acceleration than sumo. However, lifters with a sumo set-up experienced less time in the transition phase of the lift, which is commonly referred to as the sticking point (Escamilla, et al., 2000).
Angular Kinematics
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A powerlifter approaching the barbell with a conventional style set up will have a relative hip angle of around 69 degrees, a relative knee angle of 125 degrees, and a relative angle at the ankle of 46 degrees. As the bar reaches peak velocity, the relative angles of the joints mentioned earlier would be 85 degrees at the hip, 142 at the knee, and 63 at the ankle. At the sticking point, the relative angle of each joint would be 95 degrees at the hip, 150 at the knee and 71 at the ankle (Hales, Johnson, & Johnson, 2009). The absolute angles of the trunk, thigh and shank are also important variables to consider throughout the movement. At the initial phases of the lift, the absolute angle of the trunk is 68 degrees, 40 degrees at the thigh and 46 degrees at the shank. At peak barbell velocity, lifters can expect an absolute angle of 61 degrees at the trunk, 51 degrees at the thigh, and 63 at the shank. As the bar slows down and lifters reach their sticking point, the absolute angles are at 58 degrees at the trunk, 57 degrees at the thigh and 70 degrees at the shank (Hales, Johnson, & Johnson, 2009).
Powerlifters observed at the same meet referenced earlier, the 12 powerlifters pulling sumo had a relative hip angle at 77 degrees, a knee angle at 126 degrees. As the barbell came above the knee and lifters approached the lockout, their relative hip and knee angles were at 106 degrees and 153 degrees. At the sticking point, they were observed to have relative angles of 111 degrees at the hip and 152 at the knee (Escamilla, et al., 2000). Looking at things from an absolute angle standpoint, at liftoff the powerlifters were at an angle of 33 degrees at the trunk, 145 degrees at the thigh, and 80 at the shank. At the point where the bar passes the knee, the trunk would be at an angle of 46 degrees, the thigh at 126 degrees, and the shank at 79 degrees. At the sticking point of the lift, the trunk is at 51 degrees, the thigh at 126 degrees and the shank at 77 degrees (Escamilla, et al., 2000).
Linear Kinetics
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In the above free body diagram, I have demonstrated that the sumo deadlift has an almost completely vertical ground reaction force, this is because the shank is also almost completely vertical. Since the conventional deadlift puts the ankle in a more dorsi flexed position and the knee is more forward, this causes the ground reaction force to have a more horizontal component.
Force Concepts
One important concept that applies to both variations of the deadlift is Newton’s second law, which is the net force is equal to the mass of an object multiplied by its acceleration. As mentioned earlier, conventional style lifters typically take significantly less time to reach peak barbell velocity, and also have a higher magnitude of peak velocity than the sumo counterparts. Conventional style lifters also experience a greater amount of time in the deceleration phase of the lift. The deceleration phase (sticking point) is typically where a lifter will fail on a maximal attempt, so the less time spent in this phase, the more likely a lift will be successful. The difference in linear velocities between the two is around 3-4% (Escamilla, et al., 2000). So since the conventional approach has been shown to have a greater acceleration at similar masses, this means that there is a greater amount of force production. If performance in a meet was just based on force production, this would mean that the conventional style lift would be the superior setup.
Another important concept to consider for the optimization of performance would be the concept of work. Work is equal to the force multiplied by the distance. In this case,The wider sumo stance allows for a smaller magnitude of displacement for what USAPL would consider a legal lift, which is why conventional deadlifters have significantly higher magnitudes of mechanical work done in the same legal movement. The difference in displacement between conventional and sumo deadlifts are generally around 2-3cm , and the difference in mechanical work is around 25-30%(Escamilla, et al., 2000).This information would suggest that athletes who perform a sumo deadlift should be able to perform better in a powerlifting meet than their conventional counterparts.
Angular Kinetics
Since the sumo deadlift involves a more upright trunk during the lift, it allows the athlete to have the barbell positioned closer to their center of mass, which allows for a better mechanical advantage due to leverage compared to a conventional style. This also produces less strain on the lower back, which will be discussed in greater detail later in this paper (Escamilla, et al., 2000). This information would suggest that the sumo deadlift would be the superior approach to picking up the most mass in a powerlifting meet when compared to a conventional style lift. Below is a chart of the joint moments and moment arms in the sumo and conventional deadlift at different positions throughout the movement (Escamilla, et al., 2000). At liftoff, the torque at the hip is similar between the variations, but is much greater at the ankle and knee for the sumo. At lockout and mid lift, the torque values for the ankle knee and joint all have a greater magnitude in the sumo deadlift. 📷
Skeletal Considerations
The deadlift has been found to be a great exercise to treat low back pain and to prevent or reverse bone degeneration This is because the deadlift has a high magnitude of strain and a high strain rate. In 2019, Watson, et al. studied the effects of high intensity exercises such as the squat and deadlift on postmenapausal women with bone degenerative disorders.They started them out with body weight squats and progressed them into heavy resistance training exercises such as squats and deadlifts (around 85% of the participants 1RM), and after 8 months of intervention, they were found to have better scores of bone mineral density, with the greatest positive result being in the lumbar spine. It should be noted that the control group in this study experienced a general decrease in bone mineral density, while they were working at loads lighter than 60% of their 1 repetition max. Since both exercises can involve so much load, both variations could be performed to improve the health of the skeletal system.
When training heavy, while forces on the spine can be good for spine health, it is important to reduce the risk of acute injury. The compressive forces on the discs in L4 and L5 are roughly the same, however, the shear forces found on the L4/L5 region is significantly higher in the conventional deadlift opposed to the sumo deadlift (Mcguigan & Wilson, 1996). Wearing a tight belt around the abdominal cavity can help increase the intra abdominal pressure and reduce the amount of compression and shear forces on the spine. Increasing the intra abdominal pressure can allow the abdominal cavity to bear up to 50 percent of the load that would normally be placed on the vertebral column (Escamilla, Francisco, Kayes, Speer, & Moorman, 2002).
Muscular Considerations
One interesting observation included in research is that in the lighter weight classes in powerlifting, the mix of sumo and conventional deadlifters is even. However, the heavier the weight class, fewer and fewer athletes are seen performing sumo deadlifts. In the weight class of 90 Kg and the weight classes above it, about 85% of athletes used the conventional set up versus the 15% that used sumo (Escamilla, et al., 2000). This could be due to the greater amount of muscle mass heavier athletes would have, making it more difficult to get into a good position with their hips in a sumo deadlift.
The sumo deadlift has been shown to get greater muscular activity in the knee extensors and dorsiflexors, whereas the conventional deadlift will recruit more plantar flexors. There was no significant difference in the activity of the hip extensors (Escamilla, Francisco, Kayes, Speer, & Moorman, 2002). Lifters performing the conventional deadlift were found to have twice as much muscle activation in the erector spinae than those performing a sumo deadlift (Mcguigan & Wilson, 1996).
APA References
Ball, R., & Weidman, D. (2018). Analysis of USA Powerlifting Federation Data From January 1, 2012–June 11, 2016. Journal of Strength and Conditioning Research, 32(7), 1843-1851. doi:10.1519/jsc.0000000000002103
Escamilla, R. F., Francisco, A. C., Fleisig, G. S., Barrentine, S. W., Welch, C. M., Kayes, A. V., Andrews, J. R. (2000). A three-dimensional biomechanical analysis of sumo and conventional style deadlifts. Medicine & Science in Sports & Exercise, 32(7), 1265-1275. doi:10.1097/00005768-200007000-00013
Escamilla, R. F., Francisco, A. C., Kayes, A. V., Speer, K. P., & Moorman, C. T. (2002). An electromyographic analysis of sumo and conventional style deadlifts. Medicine & Science in Sports & Exercise, 34(4), 682-688. doi:10.1097/00005768-200204000-00019
Hales, M. E., Johnson, B. F., & Johnson, J. T. (2009). Kinematic Analysis of the Powerlifting Style Squat and the Conventional Deadlift During Competition: Is There a Cross-Over Effect Between Lifts? Journal of Strength and Conditioning Research, 23(9), 2574-2580. doi:10.1519/jsc.0b013e3181bc1d2a
Mcguigan, M. R., & Wilson, B. D. (1996). Biomechanical Analysis of the Deadlift. Journal of Strength and Conditioning Research, 10(4), 250-255. doi:10.1519/00124278-199611000-00008
Vecchio, L. D. (2018). The health and performance benefits of the squat, deadlift, and bench press. MOJ Yoga & Physical Therapy, 3(2). doi:10.15406/mojypt.2018.03.00042
Watson, S. L., Weeks, B. K., Weis, L. J., Harding, A. T., Horan, S. A., & Beck, B. R. (2017). High-Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical Function in Postmenopausal Women With Osteopenia and Osteoporosis: The LIFTMOR Randomized Controlled Trial. Journal of Bone and Mineral Research, 33(2), 211-220. doi:10.1002/jbmr.3284