The deadlift is a heavy compound movement that should be included in the exercise program of any lifter. As this lift will strengthen not only the entire back, but the musculature of the hips, abdominals, and legs, as well as work the grip, proficiency in this lift is a must. Like the squat, the deadlift will stimulate a growth response from the body that should carry over into strength and size gains in other areas.
There are two basic styles of deadlifting, conventional and sumo. Each style will be explained, and compared to the contrasting style. While certain aspects of deadlifting are similar, such as the fact that the lifter is basically picking a weight up off of the deck, and raising to the highest possible level without bending the arms, a great many differences in biomechanics occur as a result of the differing styles.
The conventional stance consists of the athlete standing with the feet approximately shoulder width apart, or slightly narrower. To position the feet properly, slide them forward as far as possible without moving the shoulders in front of the bar. The hips should be as close to the bar as possible as well, but the lower back must remain arched. The head should be elevated so that the athlete is looking forward and slightly upwards. The shoulders should be back, but slightly rounded. Retracting the shoulders causes the shoulder girdle to elevate, increasing the distance the lifter must pull the bar. The athlete must grip the bar tightly, and to ensure that the bar does not roll, a mixed grip (one hand supinated, one hand pronated) is often employed.
The true beginning of the deadlift is the set up, or the first phase (as it is known in Olympic lifting), which has already been described. The next step, before pulling the bar free from the deck is to fill the abdominal cavity with air. While drawing in as much air as possible, the goal is to push it down as far as possible, not fill the chest cavity. Filling the chest cavity with air elevates the shoulders, which will increase the distance the lifter must pull the bar.
The deadlift is initiated by simultaneously extending the knee and hip joints. The knee will extend due to the contraction of the quadriceps muscles (vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris), and, during the extension, may move slightly to the rear. The hip joint will extend secondary to the contraction of the gluteus and the hamstrings (biceps femoris, semitendinosus, and semimembranosus). While the entire hamstring is active to a certain degree during the deadlift, the semitendinosus and semimembranosus are recruited to a much greater degree to extend the hip joint.
The bar should be pulled into the body, as well as up. This keeps the athlete from falling forward during the lift, as it helps maintain a far more stable combined center of gravity (CCOG). This is where the placement of the feet is a significant factor. If they are too far forward, causing the shins to be closer to the bar than necessary, the bar must be pulled around the knees, instead of past them. This shortens the lever arm distance and reduces the resistive torque.
During this period, and indeed, throughout the entire lift, the musculature of the upper back and shoulders (trapezius, latissimus dorsai, teres minor, subscapularis, infraspinatus, supraspinatus, as well as the anterior, medial and posterior deltoids) will be undergoing an isometric contraction to hold the bar in a stable position. In the arm, the biceps brachii, brachialis, and brachioradialis will also contract isometrically to stabilize the elbow joint. The forearm flexors are extremely active during the gripping of the bar.
The erector spinae (iliocostalis thoracis, iliocostalis lumborum, longissimus dorsai, and spinalis dorsai) will contract during the lift, along with the intertransversarii, interspinalis, rotores, and multifidus muscles to bring the spine into an erect position. These muscles become more active once the back is extended past a point that would be 60 degrees away from vertical. The inter-transversarii, interspinalis, rotors, and multifidus will also serve to stabilize the vertebrae and discs. In the conventional deadlift, the torso is inclined far more than in the sumo style, in direct contrast to recommendations for a more erect torso to reduce shear force on the lumbar vertebrae (4, 9, 12).
As the bar travels past the knees, and up the thighs, several key points must be noted. It is imperative that the knees not re-bend once they have begun to straighten. In addition to the extra strain this will put on the ligaments and tendons, secondary flexion of the knees (hitching) is cause for disqualification during a competition. Another mistake that is often made as the lift nears completion is the lifter will try to pull the torso back, when it is far easier to simply push the hips forward. This technique will allow the athlete to shift some of the strain from the erectors to the larger muscles of the hips, including the gluteus. At the top of the lift, the shoulders should be pulled back to indicate the completion of the lift. This is not necessary for routine training of the deadlift, but a powerlifter should practice this to avoid unnecessary red lights.
The major difference that occurs in the sumo deadlift is the placement of the feet. They are placed much wider, sometimes even twice shoulder width, although this is an extreme. The toes are turned outward, sometimes to the point where the angle of the feet approaches 160 degrees. There are several biomechanical advantages to this stance. The distance the bar must travel is greatly lessened as the hip angle is on average 12 degrees greater than the hip angles of conventional deadlifters, while the knee angle is approximately 13 degrees greater. (7, 12) The trunk angle is significantly closer to vertical, which, from a pure safety standpoint, the sumo stance decreases both L4/L5 moments as well as shear forces. (4) Furthermore, the sumo stance allows the lifter to keep the bar closer to the body, which shortens the movement arm to the lumbar spine. (12) This stance can reduce the total distance the bar travels by as much as 25% - 40%. (7)
The functional technique in the deadlift is different as well. The athlete pulling a conventional deadlift will push straight down with the feet, whereas in the sumo deadlift, the knees must be pushed out over the toes. This is important, to avoid lateral shear force on the knee, as well as the fact that it allows the lifter to engage the larger muscles of the hips earlier than in the conventional stance. As a function of the bar being closer to the lifter, it will contact the legs earlier. As the bar slides up the thighs, it is important to ensure that the fingers of the pronated hand are not torn open by the friction thus generated. A modest amount of baby powder or talcum may be applied to the legs to reduce the chance of this occurring.
One factor that has not been discussed that makes the deadlift unique among the three powerlifts is that unlike the squat and bench, there is no eccentric (lengthening, or lowering) portion prior to the concentric (shortening, or raising) of the bar. This has the function of negating the stretch reflex, a fact that is often overlooked by many athletes and coaches alike. There is a way of generating a small stretch reflex, which may help when initiating the lift, but nothing like the reflex that can be generated during the other two powerlifts. In the conventional stance, a slight rocking of the hips, which will cause the knees to flex as well, can be employed. The lift should be initiated when the hips are at the lowest point, and this movement must occur rapidly. Care must be taken when doing this, as if the hips descend too far, the lifter will be at a biomechanical disadvantage.
Unsurprisingly, there is a difference when using this technique when pulling sumo. This technique (often called diving) can allow the sumo lifter to generate a greater stretch reflex without moving out of position, unlike the conventional deadlift. Because the feet are father apart, instead of just raising and lowering the hips, the hips should be lowered rapidly then thrust forward at the bottom of the descent. This allows not only for a greater stretch reflex, but for an even more erect torso than lifters who pull from a static position....