Cramps can interrupt an otherwise perfect yoga session. They are distracting to say the least. I've been trying to come up with some ideas as to what one might do to reduce foot cramps, which is the type of cramp I see most often in a yoga class. This article outlines some possible causes and suggests some possible remedies. It was difficult to find any large scale science on this question. It might be out there but I didn't find it, so take this article with a pinch of salt. That said the below may be of interest, especially if you suffer from foot cramps in bed at night, while swimming or in yoga classes.
1. What is "cramp"?
Cramp is a sudden, uncontrolled muscle contraction that sharply tightens and shortens a muscle. It's usually temporary and non-damaging, but can be very painful, and brings on a paralysis-like immobility of the affected muscle. It'll stop you in your tracks while practising yoga and make you come out of a posture (āsana) or disrupt the peace that arises while working with your breath (prāṇāyāma).
There is generally no warning that you're about to suffer cramp. Onset is usually sudden, and it resolves itself on its own over a period of several seconds, or minutes.
The most common type of cramp I see by far in my yoga classes are foot cramps.
2. When do we get cramp in the foot?
Cramps in the foot during yogāsana [yoga postural practice] can happen at any time, but especially during the cold months of the year. Certain āsana-s set them off more than others. In particular, any pose where the foot is in strong plantar flexion - where the foot points away in the same direction as the lower leg. For instance, in Vajrāsana (a version of which is pictured) or in cakravākāsana [ruddy goose or cat pose].
Or, foot cramps can be triggered when the foot comes into dorsi flexion - where the foot comes towards you, for example, when doing paścimatānāsana (a form of which is pictured).
We can also experience cramping when the foot turns inward. This can happen in cross-legged positions like siddhāsana [pose of accomplishment].
What is common to all of these movements is that the foot is being moved or stretched into positions it is not used to.
If we take the view that yoga practices, in this case yogāsana, teach us something about ourselves, then we might move beyond saying something like: J'accuse ... yoga for causing my cramp! Instead, we might start looking more objectively for better explanations for our foot cramps.
3. Why might we get foot cramps?
Why we get foot cramps depends on a range of factors. This is, of course, another way of saying "it depends" or that "no body really knows why" we would be getting them.
It might be that:
Your feet are cold. In fact, wearing socks while practising does appear to reduce the risk of getting cramps, especially in winter or while practising on cold floors. Socks need to come off for a few āsana-s, but generally, socks can be worn throughout most yoga classes
Your muscles are fatigued. This is not a major issue for those exercising on a yoga mat unless your yogāsana session is very long and strenuous. Long distant runners, for example, are more likely to suffer cramp during or after a run than yogi-s during or after a yoga session
There are medical reason such as:
An electrolyte abnormality like potassium (too little) , calcium (too much) or magnesium (too little)
Vitamin B1 deficiency
Poor blood circulation (intermittent claudication), particularly in the calf muscle
Medication side effect, e.g. medication for high blood pressure or high cholesterol can increase the chance of cramp
4. The most common cause of foot cramp
However, the most common reason is probably to do with the plantar intrinsic muscles, which are found in the sole of the foot between the heel and the toes. These are a complex array of muscles in four layers under the foot.
Now it may be that the propensity for cramps has something to do with the Western habit of wearing shoes, and in particular shoes with heels and toe springs.
Shoes with heels have the effect of shortening the muscles of the back of the leg.
The design of many shoes, including athletic shoes, incorporates a "toe spring" which can be a toe-deforming shoe feature. The toe spring in your shoe raises your shoe's toe box above the ground by as much as 15 degrees. The effect of this feature is to shorted the muscles in the front of the foot and leg.
Modern shoes have both raised heels and a toe spring: a double whammy.
4. Muscle imbalance
So, if we go along with the idea that our shoes have been busy shortening the muscles in the front and / or back of our feet and legs, then we can imagine that some āsana-s, like the ones mentioned above, will result in cramp. Some āsana-s have the effect of overstretching the muscle in the foot and or lower leg and this can produce foot cramp.
In fact, anything that pulls down on our toes, when we have these shortened muscles as a result of wearing popular western shoe designs, can cause cramping. For instance, swimming can pull down the front of our feet and toes as can sliding ones feet between the bed sheets.
In order for your foot muscles to function efficiently, they need to be in their proper length to tension relationship and that might mean shoes without heels or toe spring.
Shortened muscles have to be lengthened slowly and carefully over a long period of time. Therefore, we must proceed intelligently - step by step - with any remedy we might try applying under appropriate advice. We should give time to bring about the changes we need to avoid future cramps.
5. Towards Fewer cramps
I'd like to suggest that the way to reduce foot cramps is a simple matter, but it probably isn't. If the cause is muscle imbalance, then some ideas, however, might be worth considering:
flatter or flat footwear
introduce carefully and intelligently some barefoot walking
introduce carefully and intelligently toe extensor excercises. For instance, alternately curl your toes under and lift them up. Add some toe pointing. Start gently and build up. These movements could be added to āsana-s like ūrdhva-prasārita-pādāsana [upward raised leg posture] or apānāsana [knees to chest posture]
You might also want to review your intake of electrolytes. One cause of cramping is an imbalance between calcium (too much) and magnesium (too little). Calcium and magnesium work together and the Western diet tends to be low in magnesium: we don't eat enough leafy green vegetables! Leaves are green because of chlorophyll and chlorophyll is a great source of magnesium. Magnesium is a muscle relaxant, among other things.
The Western diet is also low in potassium and potassium, among other things, has an important role in muscle function. Potassium comes from vegetables and fruits too and unless we are eating 7 or more portions of plants a day we probably are not getting enough potassium. In addition to not getting enough potassium in our diet, stress or sugary food deplete our potassium levels.
Yoga, of course, is widely recognised as a stress buster. And it is a great way to learn about yourself. When we foot cramp during our yoga practice we can take that as a clue that something is going on in the body and if it happens often we can investigate further and decide upon a suitable course of action.