Physio Phriday introduces… ‘Exercise-induced cramps. What are they?’

We’ve all experienced the excruciating pain of  muscle cramps before. They can hit us at any given time…whether we’re exercising, just after we’ve exercised, whilst we’re relaxing with our feet up or asleep in bed. Although we all know what they feel like, very few of us know what causes them and how we can prevent them. In order to understand the background to cramps, you’ll have to don your junior cert biology hat….just for a moment.
What causes cramps?
Research has found that exercise induced cramps are caused by an imbalance in the central nervous system and the musculoskeletal system. The muscle spindles and golgi tendon organ (sensory receptors in the belly of the muscle, which detect changes in the muscle length) play a fundamental role in the maintenance of muscle length and congruity. Disturbance in the activity of these may be caused by dehydration, muscle shortening, over exercising, fatigue and poor posture/biomechanics. Any of the above contributors can lead to over activity of the motor neurons (cells located in the spinal cord which control muscle movement), resulting in over recruitment of the muscle itself. In an over-worked fatigued muscle, the relaxation phase is somewhat compromised leading to the potential of over activation of the motor neurons resulting in a high firing frequency. Hey presto… You’ve now got yourself a cramp.

Treatment of cramp aims reduce muscle spindle and motor neuron activity by inhibiting the reflex movement and forcing the muscle into an extended position. There are no actual proven strategies for the prevention of exercise-induced muscle cramp, however there are PLENTY of well known top tips.

1. Muscle stretching– by keeping the length of the muscle in tow and cooling down following activity, you will reduce the risk of cramping.
2. Keep hydrated– sweating during exercise can lead to salt and water loss which results in poor muscle function, leading to cramping.
3. Electrolytes and potassium– research suggests that low levels of potassium and electrolytes can result in cramping. Stock up on bananas and dioralyte sachets as part of your diet.
4. Don’t skip rest day– exactly what it says on the tin. Don’t over train as this will over-exert your muscles.

From a physiotherapy point of view, cramps are part and parcel of our weekly case load. It is almost impossible to completely avoid cramps whilst training, however you can absolutely reduce the risk of occurrence. Exploring different training regimes such as ….plyometrics (jump style training) or eccentric muscle strengthening (weight training) alongside a healthy diet (don’t forget the carbs!) will undoubtedly help to keep cramps at bay.
Hands-on physiotherapy such as trigger point release and dry needling have been shown to aid muscle lengthening and inhibit over activation in addiction to speeding up recovery.

So there you have it. Cramps aren’t fun. Take into account all of the above tips and keep your training cramp free.


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