Q: Why Do My Feet Cramp Up When I Do Cobra?
A: Foot cramps in bhujangasana have any or all of three potential causes:
> the position of your body may get in the way of circulation to the legs and feet (inadequate blood supply)
> lengthening the front of your body may cause a neuromuscular hyper-response (altered neuromuscular control)
> misfiring of muscle groups that are used to firing in a different sequence (coordination)
A cramp is a strong involuntary muscle contraction. When a muscle cramps it usually stays cramped until we stop doing whatever set it off. For quick relief in most situations, you can release the muscle by changing how you’re doing what you’re doing when the cramping begins.
For example, side stitches in running are often helped by deliberately focusing on and changing the foot you are inhaling on in your breathing rhythm. Similarly, in yoga, come out of the posture as much as you need to (or entirely), shake out the limb, do the posture on the opposite side, or do a counterpose. Rubbing the muscle or stretching it will often help the cramping to stop.
Many of us have heard standard advice
about dehydration leading to electrolyte deficiencies as the cause of cramping (low potassium, calcium, or magnesium are the usual cramp suspects), but you might be surprised to hear there’s questionable support for some popular theories about why muscles cramp.
South African researcher Martin Schwellnus, at the University of Cape Town, published a review of the literature in the British Journal of Sports Medicine this year on exercise associated muscle cramps (EAMC) declaring, on the basis of “current scientific evidence” the theory that cramps are caused by low-electrolyte levels is merely unsubstantiated hypothesis as “the quality of experimental methodology varies considerably among studies that are commonly cited.” Case studies supporting the deficiency theory number only 18 and consist of clinical anecdote, Dr. Schwellnus says, the proposed physiology is “implausible,” and the size of the single controlled study is 10 participants.
Even the Mayo Clinic admits, “In many cases, the exact cause of a muscle cramp isn’t identified.”
If you’re dealing with chronic or repeated cramping, definitely ask your physician about it. If you’re finding that you experience cramps only with certain activities or postures,
the cause is potentially more about biomechanics than biochemistry
Let’s explore those possible causes of cramping, beginning with inadequate blood supply. For some of us, cobra, or bhujangasana, may constrain blood circulation to the feet. Depending on the shape of your bones, and the flexibility and body awareness you have, your sacrum may be tilted strongly into the lumbar spine and/or your femur may rotate deeply into the hip joint; and, in any case, the tops of your legs are pressed intently against the floor.
￼In the picture above, red indicates oxygenated blood flowing away from the heart toward the distal points, for our purposes, the feet. Looking at the legs, you can see how blood flow in the common iliac artery could be reduced by the position of the torso in cobra, and that this effect could be further amplified by flow of the femoral artery also being decreased by pressure.
Restriction of the flow of blood is one of the healing mechanisms of posture practice: as the blood flows back into a briefly deprived area, it flushes out toxins and renews the area with nutritious fluids. However, inadequate blood supply is particularly likely to cause cramping if the posture is done before there is sufficient blood flow in the artery. Remember, warming up not only stretches the muscle, it increases circulation to the muscle. Improving circulation by warming up will mean fewer injuries as well as fewer cramps.
“Altered neuro muscular control” is a real mouthful
It covers a lot of ground when it comes to cramping and athletic injuries, and any injury to joints. Throughout your body, thousands of stretch receptors report to your nervous system about the position and activities of your body at any given moment. This is called proprioception and it’s critical to all sorts of life functions from balance to neurotransmitter release. Your habitual patterns of movement and stretch receptor information may be altered by anything from overuse, novelty, and fatigue to trauma.
(By the way, knee pain sufferers: there’s wonderful research on the effects of altered neuro muscular control on the angle of load bearing in the knees of previously injured individuals. Dr. Timothy Hewett, director of the Sports Medicine Biodynamics Center of Cincinnati Children’s Hospital says “proprioception and neuromuscular control of the knee are compromised after ligament injury and must be regained” to repair the nervous system’s body image – something yoga is superb in accomplishing. The down low is that
once you’ve damaged the connective tissue around a joint
you have effectively silenced the stretch receptors in the damaged area. Until and unless you engage in an effective therapy, your joint remains at higher risk because your brain is often guessing about the missing information, and guessing just imprecisely enough to put the already vulnerable joint at continued risk – hence frequent soreness and re-injury.)
Muscles work in pairs of “antagonists.” The contraction of one muscle causes the extension of another. It’s fairly common to shorten the front of your body, i.e. slouch, when you are fatigued, whether you are emotionally, mentally, or physically tired. You bend over backward when you slouch, you curl forward and inward. In part this is because there are so many short powerful flexors on the front of the body (abdominal muscles, biceps, quadriceps, and your chest muscles, or pectorals) and because of the core body fascia of what Tom Myers names the “deep front line” connective tissue becoming shortened as your habitual range of motion decreases. This means the muscles on the back of the body must tone and shorten to oppose and lengthen the front of the body.
In cobra, then, the cramping can be caused by novelty and fatigue: if you think about it, very little that you do in day-to-day movement resembles a cobra posture. When we supply tone to the back of the body though floor postures with a prone backbend (face down, arching the back), the intense change in the length of the muscle can cause it to spasm and/or cramp when the stretch receptors in the muscles suddenly send unusual information to the nervous system. Your autonomic nervous system (sometimes called “involuntary” because there’s no conscious choice involved) responds rapidly to stabilize your movement. Some of us, as a result, experience cramping in the hamstrings as well as the feet.
Lack of muscular coordination is the third potential cause of cramping in bhujangasana. Yoga postures feature many unique requirements for coordination. This is part ofwhat makes yoga so remarkably effective for addressing everything from depression and anxiety to PMS, autoimmune disorders, physical rehabilitation and insomnia.
The conscious attention we are directing is barely half the story.
Our instinctive, habitual and reflexive responses to physical demands become deeply coordinated over our life times; yoga wakes up the physiology, neurology and anatomy of our day-to-day lives through its many endlessly attuned, specific, and non-habituated movements. As a result, coordination from the most subtle to the gross motor level is refined and improved.
We all do things our own way right down to how we reach out and pick up a jar. Try brushing your teeth or writing your name with your other hand. Muscles coordinate with each other to perform right down to the timing of how closely some muscles contract together or how quickly they contract sequentially. Track stars have very strong muscles as we know, but much of their speed comes from the elite coordination of the simultaneous and sequential contractions.
Lack of coordination in cobra isn’t rare, but it may be hard to notice until a muscle responds to the strangeness of the request to coordinate in a new combination of timing and sequence. Many of us have been taught to focus strongly in the low back (hip and pubic bones pressed strongly into the floor). However, the length in your legs should come from the top of the foot through the shin and quadriceps, hip flexors and pelvic floor before the body begins its upward arc.
Adjust yourself so that you can comfortably extend the ankles out of the tops of your feet when you are lying face down, bringing your feet together so your legs from your big toes to your inner thighs are touching. Press the tops of the feet down and feel your legs begin to lengthen forward in a serpentine way into your hips. You will likely need to pause to adjust the placement of your hip bones a little forward to make space for this new length in your legs, an extension of the front of your body that comes from more efficient contraction along the back of the body. If this action brings on cramping, come out of the posture entirely and repeat warm ups for your legs with special attention to feet, ankles, and calves.
Additionally, come into bhujangasana with more attention to the sacrum.
Distribute the back bend along the spine rather than relying on the sacral joint to accommodate the entire range of motion.
You can do this by pausing to very slightly round in the low back as you place your hands under your shoulders- it’s not a big tucking motion, but a lengthening of the lumbar and a positioning of the pelvic floor to support the low back. With this subtle anchor in place, press gently into your hands so you can lift your abdomen a bit; keep your pubic bone against the floor, then lengthen the belly button forward, away from the pubic bone. In this way you bring some the arc of the backbend into the thoracic spine. Don’t forget to pay attention to your legs! Remain active in the entire back body as you maintain the protective attention to the low back. Bring your rib cage forward along the floor, open your collar bones and keep your shoulders broad as you lift the sternum in your back bend at last bringing the ribs off the floor.
Allow coming into cobra to receive as much inner focus and attention as coming into any posture you personally consider more challenging. Fast sharp cobras are a recipe for straining the back or sacral joint, and they do little to prepare the spine and front of the body for fully expressed virabhadrasa. Take your time with the body awareness of bhujangasana and the rewards of deeply supported heart opening will begin to bear fruit throughout your life.
Quoted and Cited
Muscle cramp: Causes – MayoClinic.com
M P Schwellnus
Faculty of Health Sciences, University of Cape Town, South Africa
Cause of Exercise Associated Muscle Cramps (EAMC) — altered neuromuscular control, dehydration or electrolyte depletion?
Hewett TE, Paterno MV, Myer GD
Cincinnati Children’s Sports Medicine Biodynamics Center, Cincinnati, OH
Strategies for enhancing proprioception and neuromuscular control of the knee.
Tom Myers, Anatomy Trains: Myofascial Meridians for Manual and Movement Therapists. Churchill Livingston, 2001.
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© 2011, The Magazine of Yoga, LLC.