Fall on Your Face to Improve your Hamstrings
The key is eccentric contraction. "Enter the Nordic hamstring exercise. According to at least half a dozen recent studies, almost two-thirds of hamstring injuries might be prevented by practicing its simple steps: After warming up, kneel on the ground, with a spotter securing your ankles. Then, as slowly and smoothly as possible, lean forward so that your chest approaches the ground. Use your hamstrings to put the brakes on your forward momentum until you can no longer resist gravity. Put out your arms at that point to stop your fall. Allow your chest to touch the ground, then push yourself upright to repeat the exercise."
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