Muscle Leg Cramps While Running: Causes, Prevention, Treatment

Leg muscle cramps, those painful muscle spasms, plague many a runner—especially during the summer and/or hard training sessions.

Regardless of the frequency of the cramps, these painful muscle spasms are total bombs.

Therefore, today I’m going to share with you some of the best treatment and prevention strategies to help you keep muscle cramps at bay so you stay pain-free and run your best for the long haul.

So are you excited? Then here we go…

Racers Vs. Muscle Cramps

Cramps hurt, and they will slow you down and compromise months of hard training by messing with your precious time (and body and mind) in a race.

In fact, according to research, roughly 40 percent of distance runners may suffer from a leg cramp—whether in their quadriceps, hamstrings, or more commonly in the calves —before crossing the finish line.

Well, before I delve into the practical stuff, let me first share with you what science has to say about muscles cramps while exercising.

So are you ready? Well, don’t cramp on yet, no pun intended 😉

Muscle Leg Cramps While Running: Causes, Prevention, Treatment

Muscle cramps are involuntary contractions of muscles.

Ideally, muscle fibers shorten and lengthen back up when they contract. But in the case of a cramp, the muscle fibers remain shortened, causing tension along with that painful sensation.

Why do they happen?

Muscle cramps usually occur as a result of repeated or extended loading of a particular muscle group that’s in shortened position.

In fact, the muscles that stay in the shortened position while running are the most susceptible to cramps. For runners, it’s, mainly, the calves, also known as the gastrocnemius-soleus muscle, that get hit the most with cramps.

And the only thing that can bring relief is lengthening the muscles to resolve the spasm.

The When

Cramps may occur during or after a run.

In some cases, these cramps can go off up to six hours after running, creeping in when you least expect them. Some runners experience these cramps at night when they are just sitting around or watching TV, doing apparently no physical exercise.

Talk about a sneak attack…

Cramps are not created equal

Muscle cramps tend to vary in severity from one person to the next. The majority is mild, but some cramps can be so painful that they shut down the muscles and cause immense pain when they seize up.

Causes of Leg Muscle Cramps

Despite modern physiology science, the exact root cause of running-induced cramps is not entirely understood. They are still a medical mystery. But that don’t mean that there aren’t theories trying to explain this condition.

There thought to be numerous of possible causes including:


According to popular belief, lack of fluid intake may lead to muscle spasms while running.

Dehydration can shorten the blood volume flowing to the muscles, which can severely impact the muscle. This is the best-known theory, but with the least scientific evidence to back it up.


The primary cause of leg muscle cramps when running is overuse—running farther or faster than your body—and muscles—can handle, or when pushing yourself outside of your comfort zone, especially when running under hot weather conditions.

As a runner, if you had too many intense workouts in a row, or have increased your running mileage too quickly, then expect muscle cramps. If you’ve never suffered from muscle cramps during your running career, then you are one of the lucky ones (or you really know how to keep them at bay, then chances you don’t need finish reading this blog post).

How to Stop a Leg Muscle Cramp While Running

The best tactic for stopping a leg muscle cramp while running can be put into three simple statements: “Slow it down, stop, and stretch the cramped muscle.”

2 stretches for treating and stopping muscle cramps

Stretch the cramped leg by doing the classical standing calf stretch.

Start by leaning into a sturdy object, like a tree or a wall with your heels flat on the ground and feet two to three feet from the object.

If your leg muscle cramps are severe, then do this: lie on your back and straighten your cramped leg in the air, while pulling your toes toward your head. Use an assistance band or a towel to help you with the stretch.

Massage it

For instant relief, you can gently stretch the spot to boost blood flow to the area and undo the spasm, helping realign the muscle tissue and restore normal function.

You can rehydrate as well. A sports drink with electrolytes can help you replace the electrolytes and fluid loss more efficiently.

After that, start running again slowly and build your speed up gradually.

Stop in Case…

…the cramping persists, then it’s more likely caused by the muscle fatiguing.

In this extreme case, you may need to call it a day, stop running and hit the showers. You can always run the next time.

In some cases, if you persist on exercising on a cramped leg, you can damage the muscle.

Prevention of Leg Muscle Cramps While Running

Sorry for saying this but there no bullet-proof method for preventing these knots from tying up your runs.

Nevertheless, here are some helpful strategies and tips that can help you prevent—or even stop—a leg muscle cramp from plaguing your next run.

Warm up and Cool down Properly

The proper warm-up is the backbone of efficient and cramp-free running.

According to the limited science on the subject, muscle fatigue—or pushing your muscles too much—is one of the main causes of muscle cramping.

If you don’t prepare yourself right for the run, then chances that you are gonna run into trouble—whether it’s muscle spasms, stomach cramps, premature fatigue, or even injury. In fact, one of the fastest ways to induce muscle fatigue when running is by skipping the warm-up.

So before you break into your usual running pace, invest in a 5- to 10-minute warm-up.

Start your run session by jogging slowly for 5-minute while taking deep breaths and releasing any muscle tension you feel in your body so you can get your muscles and cardiovascular system ready for the running ahead.

You can also perform some quick and ballistic stretches before your workout, but never over-stretch a cold muscle. Doing this can lead to injury and holding a stretch for too long before running can reduce performance.

Do the intense stretching after your runs. For that, here are three Yoga post-run stretching routines that can help.

Plus, make sure also to pace yourself right.

Therefore, if you are pushing the pace beyond your fitness level, then you are more likely to suffer from these painful spasms. Start your running session at comfortable and easy pace.

Make sure to run your first mile slower than your plan to run the last one.

And never stop running on the spot.

Instead, invest in a proper cool-down by taking the time to gradually reduce your running pace into an effortless jog, then walk slowly for 5-minute while breathing deeply before you do your post-run ritual, whether it’s foam rolling, yoga, ice therapy or taking a shower’.

For a comprehensive post-run ritual, check my post on proper recovery practices for runners here.


When you run you sweat and lose fluids, making you more likely to get leg cramps.

Of course, the link between dehydration and cramps is still hard to prove, but when in doubt, drink water. It’s good for you.

Research shows no link between dehydration and leg cramps, but what’s the worst case scenario? Staying hydrated.

That’s good thing in my book. In fact, staying well hydrated—before, during, and after running—is vital for maximum performance and pain-free running.

So you shouldn’t just rehydrate to avoid cramps, you should rehydrate because that’s what you are supposed to do when running.

When dehydrated, your body cannot cool itself, and it’s also unable to process waste or transfer oxygen to the working muscles.

If you are dehydrated, then you are heading (and running) into the wrong turn buddy.

Make sure that you are well-hydrated before, during and after your runs by doing the following:

  • Drink at least 4 to 8 ounces of water before you head out of the door.
  • During your long run drink at least 6 to 8 ounces of fluid every 15 to 20-minute.
  • If you want more, then during your longer runs—90 minutes or more—use a sports drink to replace fluid and electrolytes, as well as sodium, loss lost through sweating. Runners training for long distance races—such as marathons and beyond that—can encounter leg muscle cramps towards the end of long runs.
  • Weigh yourself before and after each run, and aim to gulp down at least 20 ounces of water for every pound lost during running.
  • Don’t run during the hottest part of the day—especially during summer.
  • Don’t use thirst as a sign of needing water. The bad news is: if you feel thirsty, you are already dehydrated.

Of course, the amount of water you need will vary depending on your weight, training intensity, weather conditions and so on. But if you abide by the above running hydration rules, you will be okay.

Replace Electrolytes

Leg cramps may be induced by excessive sweating, which leads to a significant loss in  electrolytes.

So the longer (and intense) you run, the more electrolytes deficient you become.

Why electrolytes matter?

Electrolytes, such as calcium, potassium, sodium, chloride, and magnesium, help in proper muscle contraction and the transmission of muscle impulses. Nonetheless, these vital elements are lost through sweat.

Following a well-balanced diet can keep your electrolytes stores adequate, nevertheless, if you are running for an extended period—especially under hot weather conditions—then your diet will only get you so far. You will definitely be sweating a lot, thus losing electrolytes left and right.

The most efficient way to replace electrolyte loss when running is by using sports drinks. Unlike water, sports drinks are full of carbohydrates, potassium, sodium, and other minerals.

Sports drinks, such as Nuun or other sports drinks, may be essential to rehydrate and to restore lost electrolytes during and after running. In case you can’t afford (or just don’t want to) to use a sports drink, you can always replenish your lost potassium and sodium by eating a banana or a salty snack, such as pretzels.

Racing Right

If you are racing, then you really need to pace yourself here. A muscle cramp can put a stop to your competitive spirit, so don’t get freaked out if a lot of runners pass you in the first mile.

The best strategy for coming up with a proof way for dealing with muscle cramps on race day is to train at the pace you plan to race, by doing plenty of race pace workouts, progression workouts and fast finish runs.

You may get some cramps, but you will also get fitter and be better equipped to handle those issues in a race.

In other words, you are better off cramping in training. The more you get used to pushing yourself, the better prepared you will be on race day for dealing with muscle cramps issues.

Featured Image Credit – Micolmansana Through Flickr

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David Dack


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