Hamstring Injuries Are On The Rise, But Why?

by Dr. Brett L. Lukert, DC

The incidence of hamstring injuries is growing; especially in individuals aged 16-25 where it is responsible for 33% of all lower extremity injuries. The hamstrings are a group of three muscles (semimembranosus, semitendinosus, and biceps femoris) located on the posterior thigh (back of the upper leg). They are responsible for bending the knee and moving the thigh backwards.

These large muscles are not very active during normal walking or standing. However, they are extremely important in power activities such as running, jumping, and kicking. This is why sedentary individuals can get by with weak and deconditioned hamstrings, whereas athletes and very physically active people are absolutely dependent on healthy, well-conditioned hamstring muscles.

The onset of pain is usually sudden and often occurs during an explosive movement such as sprinting, lunging, or jumping. During sprinting, the hamstring muscles work extremely hard to decelerate the tibia (shin bone) as it swings forward. It is at this point just before the foot hits the ground that the hamstrings are vulnerable, and usually become injured due to maximal activation and maximum muscle length.

Some of the most common causes of hamstring injuries include decreased flexibility, a lack of proper warm-up, tight hip flexors, increased age, fatigue, improper training, and a hamstring-to-quadriceps ratio of less than 50 percent. If the hamstrings are too weak, or the quadriceps (large muscles on the front of the thigh) are too strong, the quadriceps muscles will overpower the hamstrings resulting in hamstring injury during explosive exercise.

It is important to determine which of these factors are involved so that an appropriate rehabilitation program can be developed. This allows the individual to correct the necessary strength and/or flexibility deficits and restore proper muscle balance. The hamstrings are very susceptible to re-injury so once the hamstring is rehabilitated, it is equally important to stay consistent with adequate warm up prior to future activity. Additionally, performing sport specific training drills, core stability exercises, and plyometric work in the pre-season gives the individual the best chance to begin the season in optimal shape and prevent future recurrence.

Applying these principles of muscle strength and flexibility will help you be healthy, live healthy, and stay healthy!