Exercise-induced calf cramps are usually caused by “neuromuscular fatigue”, a combination of tired muscles and misfiring nerves.
“Nocturnal” calf cramps, leg cramps at night, may be caused by fatigue but can also happen if your hydration/electrolyte balance is out (known as homeostasis).
This article will deal with exercise-induced calf cramps. Nocturnal cramps will be the subject of another post at a later date.
What causes calf cramps?
The calf muscles are two very powerful muscles located on the back of the lower leg.
The upper muscle, Gastrocnemius (or “Gastrocs” to his friends), sits closest to the surface and is responsible for powerful movements such as jumping and sprinting.
The deeper muscle, Soleus, runs the full length of the calf and is responsible for fixing or bracing the ankle in a position, such as in steep hill running or efficient flat running.
In normal muscle function, electrical impulses from the nerve reach a threshold that triggers the muscle firing.
During calf cramps, the electrical impulse needed to trigger the nerve and muscle is reduced and the nerve signals from the spine are altered.
This causes the muscle to fire easily, with a very strong contraction that often sustains for a few seconds (although it feels like eternity!)
The sustained strong activation of the calf that occurs with calf cramps causes muscle damage, in particular to the connective tissue within the muscle.
The connective tissue within the muscle is strained and some muscle fibres are torn.
This causes small amounts of damage throughout the muscle, giving that generalised widespread post-cramp pain the next day.
How can you stop calf cramps?
There are a number of types of calf cramps and each one has a different treatment – this is where most of the confusion about effective calf cramp fixes come from.
For exercise-induced calf cramps like we see in distance running, we’ll cover prevention of calf cramps, relieving calf cramps and recovering from post-cramp muscle damage.
How to prevent calf cramps
Calf cramps during exercise are caused by neuromuscular fatigue, with contributing factors such as heat and restrictive clothing making them easier to trigger.
The trick to preventing cramping is in your prep work.
Fix #1: STRENGTH TRAINING
Strength training will delay neuromuscular fatigue. Simply put, stronger leg and hip muscles will take longer to get tired and be susceptible to cramping.
It may not prevent cramps completely, but you’ll be able to go a lot longer before they start to kick in.
Any strength exercises can help but avoid the temptation to focus on calf strength!
The stronger your calves are relative to the rest of the leg, the more the brain will engage them and the quicker they’ll be overloaded.
Instead, use a balanced mix of exercises for glutes, hamstrings, quads and calves.
Fix #2: Reduce heat exposure
Avoiding excessive heat to the calves specifically and to the body overall will reduce your chance of cramping.
In some situations, you can change your training schedule to avoid the heat of the day.
Another contributor to localised calf heat is inappropriate clothing options.
Wearing thick clothing or compression garments on hot days can increase the skin surface temperature by up to 5 degrees celsius!
Not a preventative fix: Electrolytes!
Importantly, consuming electrolytes or salts does not prevent exercise-induced calf cramps.
You can guzzle all the sports drink you like before a run, even during the run, but it won’t stop cramps from striking.
This myth has been spread widely over the years, perhaps even by sports drink companies…but has no merit.
Side note: there are cramps associated with extremely low electrolyte levels but these cramps affect all muscles simultaneously and are a medical emergency – they don’t cause isolated calf cramps.
How to relieve calf cramps once they’ve happened
Once the cramp takes hold, you’ll need to get it to release as quick as possible.
This can minimise muscle damage caused by the cramp and eases the pain it causes during and after it passes.
Fix #3: Stretching
Stretching is the most common approach to easing cramps – it’s almost an instinct to pull back against a forcefully shortening muscle.
But it’s vital that the stretching should be mild to moderate, not using a very strong force.
While gentle stretching can quickly relieve calf cramps, strong stretches can cause more problems.
With the muscle contracting so violently, forceful stretching back the other way only adds to the damage.
So don’t panic, be patient and hold the stretch until a few seconds after the calf cramps release.
Fix #4: Salty foods and drinks
While salt can’t prevent a cramp from happening, it can be part of the solution ONCE they’ve struck.
This is where is gets a little weird though – you don’t need to ingest it, you only need to taste it!
The salty taste on the tongue is enough to trigger a response from the body and alleviate the cramp.
Swallowing a salt capsule whole, which doesn’t give a salty taste, isn’t as effective as crushing it in your mouth, swirling it around your mouth then spitting it out.
Not a fix: Cramp sprays
Cramp sprays are popular as well, but remarkably ineffective.
They work by rapidly cooling the muscle, but that’s only helpful if heat is the primary cause.
The other danger to rapidly cooling an active muscle is that it can be more prone to injury as you start running again.
Rapidly cooling it slows the blood flow and, much like not warming up before sprinting, an unprepared muscle can lead to muscle tears.
Fix #5: Rest and recovery
Lastly, stop running for a while. Seems simple, and sometimes it’s impossible to continue anyway, but it’s very effective.
Just stopping your activity will help calf cramps ease as it gives the muscle a chance to recover from fatigue.
But avoid taking pressure off the foot completely as a lack of muscle resistance can add to the cramping impulse.
Instead, just walk it out. A casual walk pace will normalise nerve activity and “reset” the system.
Don’t take off to run again as soon as the cramps pass – wait a few minutes and then test the waters with a very low energy shuffle.
Recovering from muscle damage caused by calf & leg cramps
You’ll need several approaches to rapidly recover from post-cramp pain and loss of function.
Firstly, icing the muscle for several days after the cramp is helpful.
Ice can be applied for 10 minutes every few hours, which helps relieve the discomfort and can help get you walking normally again.
Sometimes anti-inflammatory medication or gels can be helpful too, although there are some risks with regular use over large areas (if in doubt, talk to your Pharmacist).
Massage or gentle foam rolling can also ease the pain and help you return to a normal walking action sooner.
Wait for 24 hours after calf cramps before you start rolling or massaging though.
A return to exercise needs to be gradual and can commence from 3 days post-cramping – that’s the time it takes for the body’s acute inflammatory response to pass.
Start with steady walking on flat ground.
Once that’s comfortable, begin to add speed to your walk.
Next you can try walking on inclines before finally trying a return to running (see our guide on safely building your running distance).
Avoid strength exercises for at least two weeks post-incident.
Strength work introduced too early tends to prolong the recovery and can potentially trigger further cramps.
Overall, just remember that you’ve got an injured muscle and you don’t want to push too hard too soon and risk making a bad situation worse.
If you’re not sure, check out our guide to ensuring that calf cramps-induced muscle strains don’t become muscle tears.