The general causes for why hamstring injuries occur are the lack of warming up or preparation for any physical activity, overall tightness within the muscles, especially in the lower back and hamstrings, and asymmetrical muscle strength, which can be characterized by the imbalance of strength and weaknesses within the hamstring muscles, quads, and/or hip flexors.
Another common time for hamstring injuries to occur is when you’re pushing off while sprinting. When driving your knee forward, hip flexion happens, which is an eccentric contraction of the hamstring. At the same time, your knee is going through flexion, which creates a concentric contraction, or flexion, within the hamstring. This stretching and shortening happening simultaneously gives more potential for muscle fibers to tear.
Lastly, hamstring injuries occur when you're decelerating your speed. During deceleration, you tend to start bending your knees more, shifting your hips back, and dropping your weight forward. When you shift your hips back, that is another form of hip flexion, as it shortens the hip flexors. When your knee and hip are going through flexion at the same time, your hamstring is more susceptible to injury.
Also during deceleration there is a quick transfer of weight either backwards or side to side when cutting. During this, knee and/or hip flexion happens too quickly, which creates an imbalance in your center and can cause hamstring injury. Typically because the hamstring is not adequately prepared either from a strength/range of motion perspective or the muscle is not used to the stress.
Hamstring injuries have different grades, or levels of severity. A grade I injury is most likely a strain, with minimal tearing. You should be able to recover for a grade I hamstring injury in a week or two. A grade II tear is where you will have some degree of actual tearing. This is classified more as a hamstring pull, and it will take more time to recover. You should be able to come back in four to eight weeks. Grade III injuries are a complete tear. This is where your whole muscle is fully ruptured. Because a grade III tear is so severe, it can take you six to eight months to fully recover.
Ways to Resist Hamstring Injuries
- Nordic Hamstring Curls: There have been studies that show how these decrease your chances of having hamstring injuries by up to 51%.
- Deadlifts With A Slight Knee Bend: Having less of a knee bend and putting more stretch will allow you to teach your body how to control itself through eccentric stretches, which will help prevent injuries from occurring.
- Good Mornings: Maintaining a good position in the back and creating more stretch within the hamstring will also help the body control itself and have more range of motion.
- Strengthening Your Lower Back, Glutes, Quads, Hip Flexors, and Core: Strengthening these will have a huge impact because your hamstrings are attached to your pelvis, so being able to control your pelvis will take some pressure off the hamstrings. Also, these muscles have a direct relationship with the hamstring, so having them be strong will help you resist hamstring injuries.
- Deceleration Drills, Sprint Variations, Spring Cycle Drills: You want to prepare your body for the physical exertion that will be replicated during the different types of stretching and deceleration actions.