When performing a straight-legged hamstring stretch, prone or standing, all I feel is a burning sensation through the calves and up into the lower back. It feels like I'm stretching the sciatic nerve but getting no stretch through the hamstrings. My question is twofold: why do I not feel the hamstring stretch in this straight-legged position? Also, given that many of my clients experience the same sensations during hamstring stretching, why are we taught to perform hamstring stretches with a straight leg?
Great questions! A few thoughts:
You mentioned standing or prone hamstring stretches. I am thinking you meant supine (i.e., lying on your back and lifting the leg straight up). The reason we have been taught to stretch the hamstrings with a straight leg is because the muscle crosses the knee, and so to lengthen at that joint, the leg needs to be straight.
First, regarding your question about why you don't feel a stretch. Check the range of motion you have with hip flexion. If your leg can come up to 90 degrees or more without moving your pelvis, losing neutral spine or without the other leg moving, then your hamstrings are not short and tight. I don't think it makes sense to stretch if there is no need to increase the range of motion.
A hamstring stretch should be felt along the muscle tissue, depending on where you have more "knots" or adhesions. If you feel a nervy, tingly kind of feeling as you describe, you might indeed be feeling symptoms of a nerve issue (it is getting stretched instead of gliding through the vertebrae). A straight leg raise is part of clinical assessments to elicit symptoms when something is wrong. When you do the straight leg hamstring stretch and feel that discomfort, and you feel more discomfort when you dorsiflex your ankle or flex your spine as well, you should think about seeking the advice of a medical professional.
In Stuart McGill's book "Low Back Disorders: Evidence-Based Prevention and Rehabilitation," he references this straight leg assessment called the Fajersztajn test. He also suggests the slumping test, meant to elicit sciatic symptoms. This test is performed by doing the following:
- The client sits on a table or chair and slumps forward. This essentially flexes the spine and the hip, increasing the nerve tension.
- If there is no discomfort, cue the client to straighten out one knee.
- The next progression would be to dorsiflex the ankle and flex the cervical spine.
- If there is no discomfort, you can feel better as a trainer that there is less of a chance of nerve involvement.
If you or a client has a tendency for this discomfort, a technique you might want to try is called "flossing." It is meant to help the nerves glide back in the appropriate movement pattern through the lateral foramenae of the vertebrae. You essentially pull the nerves from one end, releasing from the other and then switching the direction. This can be done by following these guidelines:
- Sit at the end of a table, so your legs can swing freely off of it.
- Flex the cervical spine, pulling the nerve at that end.
- Extend the cervical spine, and at the same time, extend one knee. This pulls at the lower end and releases at the cervical spine. This action allows the nerves to floss through the vertebral tissues.
- ONLY move through pain free ranges of motion.
I hope that helps!