Hamstring strength is important for all runners. Sprinters are the most likely to pull/tear a hamstring during a maximal speed run. Distance runners rarely run at their absolute maximum, but more likely their maximum for a given distance in some type of speed work. It is possible to get overuse hamstring strains, but probably more important is the impact hamstring strength plays on your posture.
The hamstring group is a knee flexor (bends the knee back) and a hip extensor (extends the leg backwards). This muscle group controls pelvic alignment. Too much pull from the hamstrings can cause a tilt in the pelvis and can alter your posture which may lead to alignment issues and eventually injury.
I have found this to be a challenging exercise that requires only body weight and some space. Don't be fooled, it is quite challenging! The focus is the maintain a straight back and fully locked hips (pressed upwards) to maintain a straight line from ankle to neck. Perform 10 repetitions on each leg and up to 3 sets on each leg. Stop the set if form breaks and you are no longer able to maintain straight posture.