Starting Strength, 3rd Edition - Mark Rippetoe [164]
Figure 7-24. The function of the hamstrings in the RDL is essentially all hip extension, both eccentric and concentric.
But more important is the difference in the fundamental nature of the two movements. The deadlift starts with a concentric contraction as the bar is pulled from the floor, and the eccentric phase is not really emphasized because the lift is essentially over after it is locked out at the top. In contrast, the RDL is like the squat in that the movement starts with an eccentric contraction, the “negative,” which precedes the concentric. The bar starts from a position of knee and hip extension, the bar is lowered down into flexion, and a stretch reflex initiates the concentric contraction back into extension. Any concentric contraction is stronger when it is preceded by this stretch reflex, due to increased efficiency in motor unit recruitment and to the ability of the elastic components of the muscles and connective tissues to store elastic energy developed during the eccentric lengthening of the muscle bellies. A jump is the best example of this principle; every time a jump of any kind is performed, it is preceded by a short drop of the hips and knees that creates a stretch reflex in the muscles about to contract for the jump. It takes a great effort of will to jump without this drop – it is such a normal part of human movement that it is very difficult to exclude. The stretch reflex also explains why bouncing the second through fifth reps of a set of five deadlifts off the floor is so popular. The majority of weight room exercises can be “cheated” with the use of a cleverly applied or exaggerated stretch reflex. I myself have “curled” 205 in this way.
But for the RDL – and the squat, the bench, the jerk, and maybe the press, depending on how it’s done – the stretch reflex is not cheating but is an inherent part of the movement. The bounce out of the bottom of the RDL enables rather heavy weights to be used in the exercise despite the fact that the quads have been excluded from helping with the movement. RDLs take advantage of the stretch reflex just to the extent that it affects the hip extensors.
The RDL starts in the rack with pins set at a position a little lower than the level of the hands in the hang position. This rack position allows for an easy, safe return to the rack in the event of a slipping grip that might lower the bar before you rack it. With a clean-width grip, take the bar out of the rack and step back just far enough to clear the pins. Assume the same stance you use for a deadlift, with heels 8–12 inches apart, toes pointed slightly out. Raise your chest, and focus your eyes on a point on the floor about 10 feet in front of you.
The whole point of the RDL is that the back stays locked in extension while the hip extensors work. Unlock your knees so that a little tension comes into the quads, but no more than enough to lower the bar an inch or two down the thighs. Very little knee-angle change should occur, although the knee position over the feet will change slightly. This position will place your knees above a point about halfway between the toes and the instep. Lift your chest up and arch your low back into a tight lock, trying to maintain this position for the whole movement. Start the bar down your thighs by shoving your hips back, allowing your hips to come into flexion with the bar never leaving the skin of the legs. At the same time, push your shoulders forward, out in front of the bar, to the familiar pulling position. As the bar approaches your knees, shove them back, too, shifting the shins into a vertical position. Drop the bar down past your knees, keeping it in close contact with the shins, and go as low as possible without unlocking your lower back. Stop just before your back begins to unlock – a position you will identify on the first few