Excessive range of motion can contribute to lower-back soreness or injury.
Behind the Blunder
We have all made this blunder at some point or another, and many of you probably still do. When lifting the hips off the leg press pad, you are doing much more harm than good. First off, if you are stuck in this habit, you are probably not controlling the weight as well as you should. The key to any exercise is being able to completely control the negative portion of the repetition, since its during the eccentric path that much of the damage to the muscle fibres occurs. So you definitely don’t want to rush or waste this contraction in any way. In addition, if you use momentum or rush the weight on the downward phase by trying to bounce out of the bottom with your hips, you end up losing many of the benefits the exercise has to offer. Second (this might not resonate with younger athletes), if you allow your hips to rise, you could be putting too much stress on the disks in your lower back.
Instead of allowing your hips to lift off the seat in order to target your hamstrings and glutes to a greater extent, raise your feet a little higher and wider to make up the difference. Then, as you slowly lower the weight, do not try and force knees to your chest, but gradually stop the momentum before that point, so you will not lose the tension in the quads. Finally, try lowering the weight just a bit, not all the way. Anytime you compensate form to accomplish a heavier load, the strict adjustment could be a shock, so take a couple of plates off and get used to doing it right.
Sit squarely in the leg-press machine and place your feet on the sled, shoulder-width apart. Keeping your chest up and lower back pressed into the back support, carefully unlock the weight from the safeties.
Bend your knees to lower the weight, stopping before your glutes lift off the pad. Smoothly reverse direction and then extend your legs to press the weight back up, stopping just short of locking out your legs. Squeeze your legs hard at the top then repeat for reps.
Leg Remedy: Leg Press Corrected
One thing to remember before climbing into the leg press is that there is no better exercise for the quads then the leg press, specifically for the teardrop (medialis). But you don’t need to bring the platform so far down to accomplish the machine’s best task. Stay controlled, stopping the momentum just before your hips are forced to rise upward. In fact, you even lose tension the further you lower the weight. So don’t worry, when you stop the weight before your hips lift off the bench, you are not stopping short on progress.