When you think of sprinting, the only time hamstrings really come to mind are when you feel tight or feel a strain/injury occur. However, hamstring strength is crucial to not only preventing injury, but improving speed as well.
Research by Yusaku et al. has shown that the majority of hamstring injuries are a result of improper hamstring eccentric strength. Injuries seen in this study typically resulted in the limb that showed greater weakness during initial testing. The difference in hamstring to quadriceps strength ratios was greater on the injured limb, as well.
During the sprinting stride, the hamstrings roles are to 1) aid in recovery (initial swing to mid swing phase) and 2) decelerate the shank of the leg (mid swing to terminal swing). Proper hamstring strength is needed during both phases to help control the full stride. For the recovery/initial swing phase, the hamstrings ability to contract quickly and forcefully helps the cycle of the stride and creates a faster turnover rate (stride frequency). If you remember from the last post, speed can be simplified down to stride length x stride frequency. If the frequency of the stride can be increased, without compromising length, the athlete will become faster.
From the point of mid swing to terminal swing, eccentric hamstring strength is needed to control the shank, or the shin of the leg from over extending at the knee. If the stride were to overextend, the athlete’s mechanics will be thrown off and force production will decrease, limiting maximal speed. By training the hamstrings in an eccentric manner, you are teaching the muscle to maintain control while lengthening. This can be done by including tempos during hamstring exercises. For example, during a standard machine hamstring curl, the athlete may perform 8 repetitions of contracting the weight as quick and forcefully as possible (to mimic recovery), pause the motion at the top of the contraction, and slowly control the weight back to the starting position anywhere from 3-5 seconds.
Hamstring strength is crucial for all athletes. If you want to enhance your running form, get faster, and remain injury free, we highly recommended incorporating hamstring strengthening exercises into your workouts!
Train with a purpose!
Sugiura, Yusaku et al. (2008). Strength Deficits Identified With Concentric Action of the Hip Extensors and Eccentric Action of the Hamstrings Predispose to Hamstring Injury in Elite Sprinters. Journal of Orthopedic & Sports Physical Therapy.