Hamstrings are quite an underrated group of muscles among runners. They usually focus on strengthening their quads. But, strong hamstring muscles enable an athlete, especially a runner make the most of their running mechanics. You can propel forward with each stride and prevent the knee from hyperextending at the same time while running if your hamstring muscles are strong enough. In short, hamstrings help stabilize the knee at each point of contact with the ground. Thus, hamstring stretches are critical for runners to maintain optimal performance.