What causes leg cramp? Most of us are familiar with the agonising, toe-curling twinge of a muscle going into intense spasm, like a knot trying to twist itself apart.
The pain is excruciating enough to take your breath away, bar the occasional stifled expletive. And then, as quickly as it comes on, the cramp disappears, and you’re left shell-shocked and sore – but mostly remorseful you ever took your tormented calf muscles (or quads, or hamstrings, or feet…) for granted. The question is: why?
A cramp is where a muscle contracts or ‘shortens’ vigorously and involuntarily, explains Dr Dane Vishnubala, chief medical adviser at Active IQ. The muscle contracts with force – often at night – and usually doesn’t relax again for a while. There are a few different things that can cause cramp, but it can also come on for absolutely no reason.
“Cramps are thought to be due to the nerves that stimulate a muscle becoming hyper-excitable – where the neurons fire off rapidly – causing a sudden onset of pain,” he continues. “The research and evidence for causes of cramp is weak, but it’s likely to be caused by a range of factors, some of which we do not fully understand.”
What Causes Leg Cramps?
Most of the time cramp strikes your legs, specifically your calves, quads, hamstrings or feet – but it can occur anywhere in the body, advises Rebecca Bossick, founder and specialist physiotherapist at PhysioLDN. While there’s no way to pinpoint precisely what’s triggering a spasm in your extremities, there could be a few underlying causes. For the most part, cramp isn’t anything to worry about and will usually disappear on its own.
Water helps your muscles contract and relax, so drinking enough before, during and after your workout is an easy way to avoid cramp. Not sure how much water you should be drinking when exercising? Here's what you need to know.
Tired muscles are a minefield for cramps – as are tight muscles. Regularly skip stretching? Don’t. This beginner's guide to stretching will set you straight.
Training too often or too hard can make cramps more likely. It’s called rest day because you’re supposed to rest. Don't believe us? Here's five things that happen when you overtrain.
Low levels of potassium, calcium or magnesium can invite cramps – oil them up by replenishing your stocks after a long workout.
How to Prevent Cramp
You can’t avoid cramp completely, but there are a few things you can do to keep calf contractions at bay. “Firstly, keeping hydrated, drinking approximately two and a half to three litres of water per day,” says Bossick – maybe more, depending on how hard you’re training.
“Use a foam roller or trigger point ball daily for five minutes to increase blood flow to your muscles,” she continues. “Post-training, you can try taking ice baths or magnesium salt baths. Regular sports massages or assisted stretching treatments can help prevent cramps.”
Hydration and replacing salts are important too, adds Dr Vishnubala, so electrolytes on board during endurance exercise could help. Make sure you’re getting enough sodium – cheese and beetroot are hardy sources; ready meals, less so. Keep your potassium levels topped with bananas, melon and avocado and load up on calcium with tinned fish and dark leafy greens.
Magnesium supplements can help transport calcium and potassium for nerve impulse conduction and, therefore, muscle contraction, says Bossick. Try oral pills, bathe in epsom salts or focus on magnesium-rich foods like nuts, seeds, kale and spinach. “However, the best supplement I have found to work for my athletes is taurine,” she adds, “one gram during or before training.”
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For many people, stretching and flexibility training is either non-existent or a five-minute afterthought at best, says Triyoga teacher Chris Miller, who specialises in yoga for sport – but the benefits of a regular practice are twofold.
“Yoga uses a combination of isometric muscle resistance holds, dynamic and held stretches for strength and flexibility, balancing poses to activate our stabilisers,” he explains. “Not only do these poses and transitions provide often overlooked stretching, they can also strengthen muscles through a full range of motion.”
Why opt for yoga over a series of static stretches? “Yoga encourages us to slow down and actually notice the details – to really feel everything that’s going on – and gain a heightened level of body awareness,” explains Miller.
“Yoga can identify imbalances from regular and repetitive training and tell us what we need: poses that inform us those tight quads need rolling, poses that tell us our calves would benefit from a massage, poses that tell us that our gluteus medius is under-active,” he continues. “Yoga shows us when we need to train harder, take an extra rest day, get a massage, or see a physio.”
Your body knows best, after all. Don’t wait for cramp to catch you out – add the following stretches to the end of your regular workout routine.
If the Problem Area Is Your Hamstrings...
Stand with your feet shoulder-width apart, bend your knees slightly, and fold forward from the hips. With your hands on your calves, pull your chest towards your right thigh. Keeping both feet flat, start to straighten your left leg as you exhale slowly. On your next inhale, re-bend the knee. Repeat this five times and then repeat on the other side.
If the Problem Area Is Your Calves...
Find yourself in downward facing dog, with a long stance between your hands and feet, knees slightly bent and heels lifted. As you inhale, lift your heels higher, and on your exhale, straighten your right leg, pressing your heel towards the ground. Repeat for five breaths on each leg, then switch legs. Repeat both legs three times.
If the Problem Area Is Your Quads...
Kneel on your left knee, stepping your right foot forward. Bringing your right hand to the floor so it’s level with your front foot. Grab your left foot with your left hand – use a strap if you need to – rotating your chest away from your right leg and pelvis. Press forwards towards your right foot and pull your left foot towards your glute, before easing off both. Alternate between pressing forwards and backwards for 10 breaths. Then repeat with your other leg.
How to Stop Cramp
Since cramp is involuntary and maintained shortening of a muscle, the sensible solution is to attempt to lengthen it, says Dr Vishnubala. In the throes of cramp, moving might be the last thing you feel like doing – but try these on-the-spot stretches by Bossick and you’ll see the spasm off quicker.
Stand in a lunge position with your affected leg behind you. Keeping your knee straight, push your heel towards the floor. Hold for 30 seconds and repeat five times.
Standing upright, grab the foot of your affected leg and pull your heel towards your glues. Hold for 30 seconds and repeat five times
Lift your affected leg onto a chair. Relax the knee of your standing leg slightly and lean forwards. Hold for 30 seconds and repeat five times.
Holding your toes, gently pull them backwards towards your shin. You could also try walking around to stretch the foot.