Quads often get the glory for being the vital muscle of the thigh, but hamstrings play just as significant of a role. They're essential for knee flexion and hip extension, which are key in speed. However, the hamstrings are also vital for deceleration, meaning that strong hamstrings help you stop, change directions and then resume that speed.
If you have access to a hyperextension machine, then you can target the hamstrings, as well as the glutes and erector spinae, all in one move. You might even see a stronger and less painful lower back after doing regular hamstring extensions.
Position yourself on the machine by placing your thighs on the padding and hooking your heels under the padded brace. Lower your upper body down, so you're hanging with your upper and lower body at a 45-degree ankle. Your upper body should be high enough that when you lower yourself, your abs should not touch the top of the equipment. Place your arms either cross in front of your chest or with your hands behind your neck.
Raise your upper body until your hip and waist are fully extension. Stick your chest out and keep your shoulders pulled back. Lower yourself back down, feeling the tension in your hamstrings. Pause for a second at the bottom, and then engage your hamstrings to raise yourself again.
The hamstring hyperextension targets your hamstring muscles, with the gluteus maximus, the erector spinae — i.e. the lower back — and the adductor magnus acting as synergists. The adductor magnus is a small muscle in the inner thigh.
If you position your hands behind your hand — as opposed to across your chest — your neck extensors act as stabilizers.