I often hear from folks asking about tight hamstrings. But the anatomy of the hamstring means that a short muscle can sometimes be mistaken for a “tight” muscle. Shortening of the muscle fibers can be caused by lack of movement or immobilization – this can be seen in people who have made a point to be non-weight bearing on one side following some kind of injury.
True tightness in the hamstring relates to the neuromusculoskeletal system. If your brain detects instability somewhere in your body, it will send a message via the nervous system to increase tone in your hamstrings. It’s a natural protective measure, but it can make us feel like we need to stretch out that muscle – even though the tightness is related to a need for stability.
To test the flexibility of your hamstring at the knee takes just minutes.
- Start by lying on your back with one leg extended straight on the ground.
- On the other leg, bend your knee to a 90 degree angle with the foot relaxed.
- Slowly extend the leg of the knee that is bent. It should extend completely, or reach about 10 degrees shy of extension. Normal hamstring flexibility at the knee joint is 170 to 180 degrees.
A simple way to stretch this if your test comes out positive is to use a luggage strap or towel around the foot, and then repeat the test steps. Effectively stretching your hamstrings can assist in injury prevention.