What to Do When a Leg Shakes During Hamstring Stretches

Rory Foster
Louisville, Kentucky

The shaking might indeed be coming from the hamstring, actually a shortened hamstring. If so, the culprit is probably the Psoas or Iliopsoas Muscle, which plays such a primary role in posture and in connecting the torso to the pelvis and legs. One of its primary functions is hip flexion and that affects the engagement of the hamstring. I suspect that her hamstring is in a shortened position due to the pelvis not being in a neutral position.

During Supta Padanghustasana, look to see if she is "tucking under to an extreme" in the pelvis with the small of her back strongly imprinted on the floor. If so, the Psoas is probably over-stretched thereby impeding the hip flexor and shortening the hamstring. Have her hold her foot with a strap or towel so she can keep her pelvis in neutral while extending her leg, or even slightly tilted forward, creating a slight hollow in the small of her back--this will cause the Psoas to be in a neutral to moderately stretched position, thus giving more release to the hip flexor and allowing lengthening in the hamstring.

Since this has been going on for some time, there might be a muscle memory (habit) postural problem with the Psoas and accompanying internal scar tissue (resistance/stiffness). Doing a parallel lunge against the wall with the spine in neutral (straight),and "kapotasana", single pigeon pose, are very beneficial stretches for the Psoas.

Susan Hayes
Meadow Vista, California

Here's what it says in the May 2003 issue of Fitness magazine about shaking:

Q: My muscles start to shake when I'm strength-training. What's causing this?

A: It could be muscle fatigue, says John Jakicic, an assistant professor of health, physical and recreation education at the University of Pittsburgh. When you're tired, the chemicals that transmit information from nerves to muscles become depleted. The result: The muscle starts to spasm. Try going a little lighter with your weights, and lift only until you feel the muscles beginning to fatigue. 'It could also be an indication of low blood glucose, calcium or potassium levels,' adds Jakicic. Eat a light snack a couple of hours before exercising. If the shaking continues or appears early in a workout, consult your doctor."

I'd refer her to her doctor. This is because I just completed a workshop for teaching yoga to people with multiple sclerosis. Some of the symptoms of MS [Multiple Sclerosis] are spasticity and tremors. Of course, you don't want to freak out your student; MS is not diagnosed unless the individual displays at least three symptoms that characterize the disease (the most common ones are fatigue and heat intolerance). But an MD should look into it, just in case.