Cramp up the heat


INTENSE PAIN ‘Crying and calling for your mum can be helpful in severe cases’.


Andrew O'Brien

The Australian Open tennis finished last week, with Caroline Wozniacki winning her first singles title and Roger Federer winning a record 20th Grand Slam. And, while I’d love to write another ode to Roger, I’d best not for fear of sounding a little bit obsessive.
There were two recurring themes across the fortnight: heat and cramps. In the first week temperatures reached 40 degrees Celsius, while the roof was closed for the men’s final after Simona Halep, the beaten women’s finalist, had to be taken to hospital with dehydration. There were numerous reports of players struggling with cramp, including a player reportedly needing to be sedated in the locker room, such were the severity of his cramps.  
Cramps are described as painful, involuntary muscle contractions that can be temporarily debilitating. Considering how often they seem to be associated with exercise in hot climates, it’s worth asking whether cramps are caused by heat. And the answer is a resounding, not necessarily!
Cramps were originally described among coal miners, and the assumption was that working in extreme heat caused them to dehydrate, and thus dehydration was blamed as the cause of cramp. Modern research has shed significant doubt on the likelihood of dehydration as the cause though, and although we have no definitive answer, the most likely cause is thought to be changes in nerve activity due to fatigue.
One hypothesis is that cramps result from changes in motor neuron excitability, due to what is known as central fatigue. Another hypothesis is that they result from spontaneous discharges of the motor nerves due to local fatigue in the periphery.
So cramps are just due to fatigue, either central (overall) or local (in the specific muscle). Simple. That’s why footballers are more likely to go down when a match goes to extra-time, and tennis players struggle in the fifth set. But why some and not others? And why is it worse in the heat? And why is it that I can almost set a clock by my own quads starting to cramp after 2 hours and 45 minutes of running?
Well, fatigue, like pain, is a complicated thing. Some of it is physical, some mental, some neurological. I’m sure a big part of my own cramping problems are psychological; I look at the watch and think, ‘Gee, I hope I don’t get a cramp today’. Then bang, there goes the right quad. Not always enough to stop me, but enough to be aware of it. To further prove the point, the moment I turn for home, the cramps ease.
Muscle fatigue is not as simple as muscles just getting tired. If it was, the hardest working muscles would likely go first, but very rarely do we hear of anyone’s glutes cramping. Thank God; could you imagine the pain? Typically the calf muscles are the most likely to be affected. It’s thought this is because the calf has a high percentage of fast twitch muscle fibres, which tend to fatigue quickest. This makes sense using the local fatigue hypothesis, whereas the ‘all over’ cramps sometimes seen at the finish line of endurance events support the central fatigue theory.
Obviously external factors such as heat can play a part, in that if it’s extremely hot, you will fatigue more quickly. Inadequate fuelling, either in the form of hydration or food, can accelerate fatigue, although not as quickly as the sports drink manufacturers might have you believe.
In a cruel twist, it would appear that some people are just more susceptible to cramp. But we can all condition ourselves to reduce the risk. Ensuring an adequate level of fitness for the activity you will be doing is a given. So too, is making sure you get sufficient rest in the lead up to an event; if you’re sleep deprived at the start, you’ll definitely fatigue more quickly during a session.
Incorporating plyometric exercises into training is widely recommended as this creates a neuromuscular strengthening effect that is typically greater than might be achieved in most other training sessions and should reduce the risk of local fatigue. If you are unfortunate enough to suffer with cramps during a session, stretching the affected muscle can provide some relief, as can massage if it’s available. I find crying and calling for your mum can be helpful in severe cases!
As to the heat-related preparation, you have two choices here, warm weather training, or just forget about it. You’re not going to get that hot in February in Ireland now, are you?

Andrew O’Brien is a chartered physiotherapist and the owner of Wannarun Physiotherapy and Running Clinic at Westport Leisure Park. He can be contacted
on 083 1593200 or at