Muscle cramp ‘teasers’. . .

19 Nov 2007 Posted by
Apologies for the absence…and some muscle cramp ‘teasers’…

Ah, the joys of the University calendar! We must apologize for our somewhat lengthy absence – it has been 5 days since we last did a post, which I think is the longest break we’ve had since we began The Science of Sport in April earlier this year!

But we have good reason, for both Jonathan and I are both deep into marking and examination of undergraduate and post-graduate exams and theses at our respective universities. Though Jonathan and I both enjoy lecturing and find it very rewarding, when we reach mid to late-November, our disposition towards teaching changes somewhat, as hundreds of exam scripts and thesis work suddenly land on our desks for us to plough through! And funnily enough, the other work doesn’t seem to realise it and let up!

So we do apologize for the break, but we’re back now, hopefully with a bang, as we get stuck into a new series, this one on Muscle Cramps – Science and Fiction.

A follow on from fluids and dehydration

The series on muscle cramps is really an extension of our last series – Fluid Intake and Dehydration. In that series, we tried to explode some of the myths around drinking during exercise, describing how the prevalent “scientific” advice was in fact flawed (sadly, it’s often fatally flawed). We looked at the claims and counter-claims and ultimately encouraged everyone to do the wise thing – listen to your body, and when it says you’re thirsty, drink! But only then…don’t let the fluid companies tell you that you’re the only mammal too stupid to know when to drink by itself!

Introducing muscle cramps – some points to ponder

The muscle cramp story is similar, sadly. In South Africa, we have a host of companies who produce cures, preventative tablets, creams and liquids to help you avoid cramp. The premise, as was the case with fluids and dehydration, is that a cramp is caused by a depletion of some electrolyte – sodium, potassium, calcium or magnesium. All have been mentioned, and most often, it’s sodium and magnesium that take the brunt of the blame.

We’ll take a step by step journey through muscle cramps in the series. We’ll tackle it in three parts:

  1. What is a cramp? Very brief history and overview of what we know, and how we know it.
  2. The electrolyte-dehydration-heat theory for muscle cramps
  3. An alternative view – evaluating the gaps in the theory

So that is what you can look forward to (or with dread, as the case may be!) over the next week.

Until then, here are some issues to ponder:

  • Despite the theory that muscle cramps are caused by electrolyte and fluid depletion, it has yet to be shown that people who cramp have lower electrolyte levels or are more dehydrated than those who do not. In fact, the studies have found that “Crampers” and “Non-crampers” have similar electrolyte and dehydration levels. Something wrong with that picture…
  • If cramps are caused by electrolyte and fluid depletion, which muscles would be most likely to cramp? Would it not be ALL the muscles, because you’re losing electrolytes and fluid through sweat, so then all the muscle groups should be vulnerable…yet for some reason, we cramp in the muscles we actually USE. Again, something out of place there.

(Some of you may already have a counter to these points, saying that what is happening in the muscle is not necessarily what is happening in the blood – we’ll tackle that one for sure)

And then finally, if you are reading this before heading off to bed, we hope that you don’t experience the dreaded “Night cramp”, which we’re sure most of you have had at some stage. You wake up in the night, and feel a slight twinge, usually in the calf. Your first impulse is to point your toe, and when you do that, what happens? You may know that if you do this, you’ll be writhing in agony instantly! Instead, what should you have done? The answer is you should stretch the muscle – stretching is the quickest way to get rid of cramp. Now, how do we explain that one according to a heat-electrolyte theory?

The answers to follow, so join us then!

Ross

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