Why do we get cramp?

It's that time of the year where more and more of us seem to suffer with unexplained cramp.

Scientists in labs have been trying to work out the exact cause for cramps and whilst the general consensus is that it might be due to ‘dehydration’ or ‘electrolyte imbalance’ the evidence in research is still not clear.

Our muscles rely on a chemical balance of 4 basic minerals:

+calcium

+sodium

+magnesium

+potassium

These are termed electrolytes a word which has been pounced on by many marketing executives helping them sell specialised sports drinks full of these wonderful ‘super special ingredients’.

It is important to note that these minerals are commonly found in water, and in various foods although in varying quantities. It stands to reason that if these chemicals are out of sync it might cause problems with our muscles and therefore has been a traditional approach to understanding cramp.

Research however, has not been able to demonstrate this, for example, in one study published in the Journal of Athletic Training, 13 men with history of cramp were asked to undertake vigorous activity in hot and humid conditions (increasing the likelihood of dehydration). The study had 2 conditions:

(1) men were given sports drinks with added salts and

(2) no liquid was ingested.

Interestingly in first condition all 13 men experienced cramps (even though they were MORE hydrated with higher levels of electrolytes). In the second condition however, 9 of the men reported episodes of cramps. This suggests that hydration and electrolyte content is not the cause of cramp.

Other studies have found similar results. For example in 2011 another study was published. This analysed the blood electrolyte levels of 200 Iron man triathletes. The levels bore no correlation to the incidence of cramp in the participants, again suggesting that electrolyte balance is not a cause of cramp.

A popular theory that is receiving more interest in science is The Neuromuscular Theory. This looks at the way that muscles are activated and inhibited in the body.  Muscles tend to work in pairs (I.e. bicep/tricep) when one muscles contracts the other lengthens or relaxes this happens via sensors in the muscle that send signals to the spinal cord and back. They are there to ensure that the muscles don’t over stretch or over-contract. For example when the bicep contracts the sensors in the tricep muscle notice that their muscle is getting super long, at a certain point they send a message across to the bicep to make it relax a bit.

The theory  suggests that when a cramp occurs essentially the sensors and signals get confused, this means the correct message does not get sent and one muscle will ‘over fire’ contracting constantly (this is what cramp is, continuous over contraction of a muscle). Often cramp occurs when the muscle is already in a ‘short’ position.

Let’s take an example of the underneath of the foot;

The muscles of the underfoot are paired up with the muscles on top of the foot. When we are on all fours and the top of the feet are on the floor these top-of-the-foot muscles (or 'dorsiflexion' muscles to be posh) are in a long position and are stretched. The under-the-foot muscles (or plantarflexion muscles) are now in a ‘short’ position.

When we start to move in this position sometimes we contract these under-the-foot muscles… now because they are already in a short position the sensors don’t register the contraction as it would normally leading to confusion… they then do not send the signals to the opposite muscle to contract and to their own muscle to relax. This leads to these under-foot-muscles to ‘fire on all cylinders’ as it were and leads to the painful cramp.

This also explains why the best way to deal with a cramp is to stretch the muscle out.

This is all well and good but now we’ve waffled through the sciency theory stuff what does that mean in practice?

Well firstly, we need to ensure that our muscles are balanced, research suggests that the muscles prone to cramping are the ones that often overwork (i.e. under the feet, calf muscles) and that the opposing muscle generally enjoys having more of a holiday. This makes sense how often do you flex your foot (curling the toes up towards you)? My guess by the moans and groans I get in class when we do that in a stretch is not often!! Try it now. Stand on your feet and try lifting the sole of your right foot up, then the left.

Secondly, stretch the area out. If you are prone to cramp in a certain muscle take time to stretch it regularly. For example if you suffer with cramp under the foot, stretching the foot back the opposite way can help. A good way to do this is to place the toes on the wall with the heel on the floor and bring your body weight onto it and towards the wall.

If you have cramp in your calf try placing the ball of your foot on a step (or rolled up towel or book) and drop your heel down towards the floor. If you’re on a towel or book, move the other foot forwards until you feel a stretch in the back of the lower leg.

If it’s your hamstring that cramps a lot, try putting your foot up on a stool/chair and lean in towards it to get a stretch into the back of the thigh.

Lastly, when in our example on all fours, for example, we need to try and keep the foot relaxed. Initially when learning a movement we tense all the muscles up until our body can work out which muscles it really needs to use. So you have 2 options,

1. Try and keep the muscle relaxed if it is not essential to the movement or

2. Don’t push so hard, perhaps move to the point BEFORE the cramp sets in, over time you can build that up so that the nervous system has time to keep up with you.