Why Do I Get Leg Cramps at Night? What Actually Stops Them (and What Does Not)

Night leg cramps are a nerve event, not a sign you are lacking magnesium, potassium or water. The nerves supplying one muscle fire in a sudden, runaway burst, usually in a calf that has been shortened for hours. Stretching the muscle will help to ease the cramp. Supplements rarely do.

In this blog, you’ll discover:

• What a cramp actually is, and whether you are lacking anything
• How to stop a leg cramp immediately
• Why pickle juice works, why a bar of soap might, and why to avoid tonic water
• When you need to take leg cramps at night seriously
• How we work with cramp-prone clients at Clinical Massage MK in Milton Keynes

It is three in the morning, and a sudden pain in your calf wakes you; it feels hard and solid. You can’t move your foot. Two minutes later it settles down, and you lie there thinking, how do I stop this?

“Am I not drinking enough?”

“Should I take some more magnesium?”

Some of the questions people ask me about the cramps. For years, my answer was usually yes. Drink more water. Take magnesium. Get some electrolytes. I said it with confidence because it was what I had been taught and what everyone around me said.

Then clients started coming back, telling me it hadn’t worked. Not just one or two. Enough that I started to get suspicious and look for answers about what actually happened in muscles when they cramped.

So I went back to the research and found two unexpected things. Magnesium and extra water have been tested repeatedly and keep failing. After roughly a century of study, nobody has fully worked out what a cramp actually is.

We do have a direction, and it changed how I think about this. A cramp isn’t a muscle problem. It’s a nervous system glitch.

What causes a muscle cramp?

A cramp is a sudden, involuntary, painful muscle contraction caused by your nerves, not something happening inside the muscle itself. It happens fast, lasts from a few seconds to a few minutes, and the muscle stays visibly knotted the whole time.

Put electrodes on a cramping muscle, and you see a storm of electrical activity coming from the nerves supplying it, well beyond anything you could produce on purpose. The muscle is not running out of anything. It is being told to contract, and the message will not switch off.

No one has identified the cause. The main theory suggests a control issue in the nerves and spinal cord, triggered by fatigue and muscle positioning. Tests keep disproving the old belief that cramps result from dehydration or low salt intake, except for one case I will mention.

The main thing to remember: increasing your chemistry won’t stop a cramp, but changing the signal will.

Do I need more magnesium, potassium or water?

Nearly everyone asks me about this, and diet deficiency doesn’t explain typical night cramps.

Let’s go through them one by one:

• A Cochrane review of eleven trials involving 735 participants found that in older adults with typical cramps, magnesium reduced weekly cramps by roughly 20% compared to a placebo. This small difference is likely negligible. The review concluded that magnesium is “unlikely to provide clinically meaningful” benefits (Garrison and colleagues, 2020). Many people claim they used the wrong type of magnesium, but I haven’t seen any trial evidence that one form is effective while another isn’t.
• Potassium and bananas: There’s limited evidence that consuming potassium helps with cramps. It only matters if your potassium levels are low, which is a medical concern on its own and needs a blood test, not just eating fruit.
• Calcium and vitamin D. Both are often blamed online. I haven’t found strong trial evidence for either for ordinary cramps.
• Studies comparing crampers and non-crampers in the same race show no difference in hydration levels. Even intentionally dehydrating participants in laboratory settings, even to a serious extent, did not increase cramp frequency. Maintain good hydration for overall health, but do not rely on it to prevent cramps.
• Helpful for one group: heavy sweaters doing long sessions in the heat. Not for general or night-time cramps.

Blood tests often appear normal in people experiencing night cramps, as the connection to low levels of potassium, sodium, calcium, and magnesium has not been conclusively proven.

A diagnosed deficiency is different, so consult your GP for management. For others, here’s my main message: I used to recommend magnesium when clients asked what might help, as it was a common suggestion. But no more. Many people still spend money on it every month, despite the lack of supporting evidence.

Why do I get leg cramps at night?

Most night cramps don’t have a specific cause, but we know which factors increase their likelihood.

You can improve your foot position while sleeping tonight at no cost. A muscle is more prone to cramping when it is shortened. Your calf muscle is at its shortest when your toes are pointed. Sleeping on your stomach or with tightly tucked bedclothes at the foot of the bed can keep your toes pointed for hours, leaving your calf muscle consistently shortened overnight. Researchers demonstrated this by having participants tighten a muscle at its normal length, which did not cause cramps. However, when they kept the same muscle short and exerted the same effort, seven out of ten experienced cramps (Bertolasi and colleagues, 1993).

Age and sitting. Night cramps tend to increase with age. A study in a general practice found that roughly one-third of people over sixty experienced nighttime cramps in the past two months, and this number rises to half among those over eighty. Sedentary individuals are much more likely to suffer from these cramps than active ones because prolonged sitting shortens and tightens the calf muscles.

Your medication list. Some medications can increase the likelihood of nighttime cramps. Many people blame statins, the cholesterol-lowering drugs, but research analysing prescribing data for millions of people shows they are not usually the cause. Instead, the research pointed to long-acting inhalers for asthma and COPD, and water pills prescribed to reduce fluid or lower blood pressure, as common triggers (Garrison and colleagues, 2012). If your cramps begin within a few months of starting a new medication, inform the prescribing doctor. Do not stop any medication on your own.

What it is not: A cramp differs from restless legs. Restless legs involve an urge to move, are uncomfortable rather than painful, lack a visible knot, and improve with movement. In contrast, a cramp is a sudden, painful lock that relaxes with stretching.

Why do I experience cramps during running or sports?

While playing football, I experienced a hamstring cramp at the 80-minute mark. My teammates helped me stretch it, which relieved the pain after a few seconds and let me finish the game;  although different from the 3 am cramp, the underlying mechanics were the same.

Exercise cramps come from fatigue and pace, not from what is in your water bottle.

The most comprehensive study on this tracked 210 Ironman triathletes during a race. It found that two factors predicted cramping: racing faster than usual and having a history of cramping. Hydration status and changes in blood sodium levels were not predictive. (Schwellnus and colleagues, 2011)

Does that mean you’re out of shape? No. It simply indicates you chose a pace you haven’t trained for, which is a different but solvable issue. Even many fit individuals experience cramping.

The pattern is consistent:

• Occurs late in the event, when fatigue sets in
• Affects muscles crossing two joints and becoming shortened, such as the calf, hamstrings, and quads
• Happens after pushing harder, longer, or on hillier terrain than your training
• More frequently in hot and humid conditions

One group differs from the others. Heavy sweaters, especially in hot conditions, might benefit from a specific sodium intake. A lab study showed that a carbohydrate and electrolyte drink more than doubled the time before cramping occurred, yet 69% still experienced cramps eventually (Jung and colleagues, 2005). For this group, fluids and salt can delay cramps, but they don’t entirely prevent them, and they aren’t effective for everyone.

Ways to instantly relieve a leg cramp

Gently stretch the cramped muscle slowly and hold it until the spasm relaxes. This method is the most dependable approach and is recommended as first-line advice in all the clinical guidelines I’ve reviewed. The research doesn’t specify exactly how quickly it works, but in my practice, a sustained stretch usually relieves most cramps within one or two minutes.

Stretches by muscle:

• Keep your knee straight and lift the top of your foot toward your shin. Alternatively, stand on that leg, shift your weight onto it, and press the heel down.
• Hamstring (back of thigh). Extend your knee, keep your heel on the ground, and lean forward over the straight leg.
• Quad (front of thigh). Hold onto a support for balance and pull your foot toward your backside.
• Foot arch or toes. Draw your toes back toward your shin, then stand and press the sole flat into the floor.

Pulling your toes upward serves two functions: it stretches the calf muscle and stimulates the front shin muscles, which then signal the calf to relax. This explains why the instruction to “pull your toes towards you” is so effective.

A few other things that help:

• Stand up and load the leg. Your body weight helps you stretch, making it useful at 3 am when bending forward feels impossible.
• A heat pad or a warm shower can help ease a tense muscle.
• Rub it gently. Stretch gradually and carefully. Stay relaxed during a spasm, and do self-massage only after it has subsided.

Painkillers do not directly relieve the cramp itself. Paracetamol and ibuprofen work too slowly and mainly help with soreness afterwards.

How can I relieve a cramp in the arch of my foot?

Hold your toes and gently pull them toward your shin until you feel a stretch. If reaching your toes is difficult, wrap a towel or dressing gown belt around the ball of your foot and pull. Alternatively, stand and press the sole firmly into the floor to help lengthen the arch with your body weight.

Foot and toe cramps are particularly difficult to alleviate because it’s hard to reach the muscle. The same basic principle applies as with calf cramps, but it requires a different approach.

Why it happens there: The small muscles in your arch behave like your calf muscles: they lock when they contract from a shortened position. Pointing your toes shortens these muscles, which is why you often get arch and toe cramps when you stretch your legs out in bed or point your foot while turning over.

What helps day to day: moving your feet through their full range, and rolling the sole over a ball or a rolling pin.

When it comes to footwear, be cautious about what you read. Common online advice suggests that arch support prevents foot cramps, but no studies have specifically tested any shoe for night cramps. That advice rests on opinion rather than solid evidence. Research has focused on how different shoes affect the muscles inside your foot. A 2022 systematic review found that minimal, flexible footwear with space for the toes to spread out can increase the size and strength of these muscles. However, no research has established whether stronger foot muscles lead to fewer cramps.

I prefer to let my feet work naturally, give my toes space, and seek support only when necessary. This preference comes from foot anatomy, not cramp research. No trials have validated this approach. If you experience nightly arch cramps and foot pain upon waking, consult a professional instead of trying to handle it on your own.

Wondering what you can drink to help with a leg cramp?

Researchers tested approximately 74ml of pickle juice. In a controlled trial, participants who drank this amount experienced cramp relief in about 85 seconds, which is roughly 37% faster than those who drank water (Miller and colleagues, 2010). Their blood chemistry remained unchanged; levels of sodium, potassium, and other chemicals showed no difference five minutes later. The small volume and slow absorption make it unlikely to reach the muscle within 85 seconds. Instead, the sharp taste likely triggers a reflex in the mouth and throat that helps calm the nerves overfiring during a cramp.

Nothing reached the muscle, and the cramp still subsided.

This strongly suggests that nerve activity rather than chemical factors causes the cramp. Chemistry isn’t the issue here.

Yellow mustard is another popular remedy; it likely works like pickle juice by triggering a reflex through its sharp, pungent flavour. A 2017 study tested drinks with ingredients like ginger, cinnamon, chilli, and mustard, and found they helped reduce exercise cramps (Craighead and colleagues, 2017). It was a small study, and no one has tested just a spoonful straight from the fridge. It’s harmless and inexpensive.

Tonic water, however, is not effective. You’d need about ten glasses to get a dose of quinine that might work, but quinine is now discouraged in the UK and US because it can cause serious side effects. Tonic water simply exposes you to those risks without delivering a therapeutic amount.

The studies used lab-induced cramps, and one independent group failed to reproduce the pickle juice result. Even so, if you are standing in the kitchen at 3 am, a swig of pickle juice is free, safe, and better supported than the supplement in your bathroom cabinet.

What is the old wives’ tale about a bar of soap?

Place a bar of soap under the bottom sheet near your feet. Many online claim it works. However, no one has tested this, and soap beneath a sheet doesn’t affect your nerves. To put the soap under a fitted sheet, you need to loosen the bedding at the foot of the bed. Loose bedding keeps your foot from staying in one position all night, which often causes calf cramps. My conclusion: the soap isn’t responsible; it’s the loose sheet that makes the difference. You can skip the soap and still enjoy the benefit.

Can massage help with leg cramps?

Massage can help ease cramps but doesn’t eliminate them. The supporting evidence is limited. It can relieve sore muscles after a cramp and reduce the tightness that triggered it. However, it doesn’t prevent cramps from recurring on its own. Combined with stretching and movement, it can help prevent tightness from returning, and many clients report feeling looser and more comfortable overall.

One common myth is that massage helps with cramps by removing lactic acid from muscles. In fact, cramps result from nerve activity, not waste buildup, so there’s nothing to flush out. Hands-on techniques can help with cramps in certain situations.

The aftermath. A muscle that has cramped hard stays sore for hours or days. Simple soft-tissue work eases the soreness, and it helps.

• The setup. The client who sits at a desk with short, tight calves and the runner with an overloaded hamstring both adopt sitting positions that increase cramp risk. That’s our focus.
• Assisted stretching on the massage table provides greater range than doing it yourself at home. My profession traditionally believed that contract-relax stretching switches muscles off, but research doesn’t support that. Instead, repeated exposure to new ranges teaches your system they’re safe. Assisted stretching doesn’t prevent cramps, but it helps loosen tight muscles and restore lost movement.
• Teaching you the routine. Which stretch, how long, when? Most people do a version of it wrong or give up after a week.

The offer isn’t ‘I will cure your cramps.’ Instead, it’s ‘Here’s what works, what to avoid spending money on, and when to see a doctor.”

What has the research actually examined: a single session or an entire course?

This is a compilation of all studies I found comparing hands-on treatments to cramps, including their findings and limitations. This is my preliminary review, not a conclusion.

Single sessions, tested four times; nothing found each time.

• Massage lowers the excitability of the nerves feeding a muscle during the treatment, and it returns to baseline as soon as the hands come off (Sullivan and colleagues, 1991; Goldberg and colleagues, 1992).
• One bout of passive static stretching did not change how easily people cramped. Panza and colleagues (2017) tested 17 people, and worded it carefully: acute passive static stretching “did not seem to increase” the cramp threshold.
• One three-minute bout of static or contract-relax stretching did the same thing in 15 people (Miller, Harsen and Long, 2018). Both increased range of movement. Neither changed cramp susceptibility.
• Manual stretching produced no measurable change in the reflex response up to 30 minutes afterwards (Miller and Burne, 2014).

Repeated courses, tested three times, something found each time.

• Nightly calf and hamstring stretching for six weeks: 1.2 fewer cramps per night in 80 adults over 55 (Hallegraeff and colleagues, 2012). This is the strongest single result on this page for prevention.
• Six massage sessions over two weeks reduced cramp frequency and severity in 36 kidney dialysis patients, including at home between sessions (Parlak and colleagues, 2024). A smaller pilot trial pointed the same way (Mastnardo and colleagues, 2016).

The pattern in these seven studies is clear.

No one has run a trial comparing one massage session against a course of them. But those seven studies suggest single sessions showed little promise, while courses of them did. It is a pattern worth knowing, but no trial has tested it directly.

The limitations:

• Both massage trials were in kidney dialysis patients. Their cramps come from fluid shifts during dialysis, which is a different problem from getting calf cramps at 3 am. The results may not be relevant.
• The studies are small, with 15 to 80 people. Small studies often miss the effects. Fifteen people finding nothing does not prove there is nothing.
• You cannot fake a massage. Neither massage trial had a placebo group, so we cannot separate the massage itself from being paid attention to and lying down for an hour.
• The single-session stretching studies triggered cramps with electric shocks in a small muscle in the foot. Not the same as a calf going in your sleep.

Another way to look at this.

The studies that found nothing measured cramps triggered in a lab. The studies that found something asked people to keep a diary at home. So the pattern goes like this: lab studies find nothing, self-reports find something. And when nobody can be fooled about whether they had six weeks of stretching or a course of massage, what people expect influences the self-reports.

Nobody has separated those two explanations. I don’t know which is right, and neither does anyone else.

What I take from this. The only prevention with positive results is repeated exposure over weeks. Every one-off attempt hasn’t deliver longterm results. That is worth knowing, and a reasonable way to think about treatment. It is not a proven rule, and if someone tests it directly, I will update this page.

How we work at Clinical Massage MK

At Clinical Massage MK in Milton Keynes, we start with an assessment, not a massage. I want to know which muscles are overworking, which have switched off, how you move, and what your day looks like. We build a treatment plan around that, using clinical massage, myofascial release, trigger point work, and assisted stretching, with home exercises to keep up between sessions.

For persistent muscle tension, a course of 6 sessions gives us enough time to see how your body responds, make progress, and decide on next steps. Many clients notice a difference within the first 3 to 4. We review as we go and adjust. Everyone is different, and we customise treatment to you.

Why does the stretching advice sound so contradictory?

It only sounds contradictory since the same word answers two different questions. Separate them, and it gets simple.

Question one: How do I stop this cramp, now? Stretch. Reliable, fast, well-documented.

Question two: How do I stop the next one? That depends on how often you stretch.

No study has shown that one stretch, on its own, does anything. Two studies tested exactly that. Panza and colleagues (2017) put 17 people through a single bout of passive static stretching and found no change in how easily they cramped. Miller, Harsen and Long (2018) did the same with 15 people, using static and contract-relax stretching. Both methods increased range of movement. Neither changed cramp susceptibility.

Both studies induced cramps electrically in a small muscle in the foot, in a lab. Not the same as a calf cramping in your sleep.

Stretching every night for six weeks is the only intervention with a positive result. Hallegraeff and colleagues (2012) randomised 80 adults over 55 to nightly calf and hamstring stretches before bed. They ended up with 1.2 fewer cramps per night than the control group, and the cramps they did get were less severe.

One trial, so treat it as one trial.

One trial, so no guarantees. It is free, safe, takes three minutes, and it is the best-supported thing you can do at home—enough for me to recommend it.

Easy actions you can begin implementing at home.

• Stretch your calves and hamstrings before bed, every night. Three minutes. One randomised trial in people over 55 found 1.2 fewer cramps per night after six weeks. One session won’t do it.
• Untuck your bedcovers. Don’t let your foot stay pointed for eight hours. If you sleep on your front, let your feet hang over the end of the bed.
• Move during the day. Regular walking counters the calf shortening that comes with sitting.
• Keep a jar of pickles in the fridge. Free, safe, and better supported than most cramp remedies.
• If you exercise, respect your pacing. Going far harder than you have trained is one of the few risk factors you can control.
• Warm the muscle when it is tight. Cool afterwards for the lingering ache.
• Ask your doctor to review your medicines if the cramps started after a new prescription, particularly an inhaler or a water tablet.
• Skip the magnesium and the tonic water. Put the money towards something with evidence behind it.

When should I worry about leg cramps at night?

Most cramps are harmless. Be cautious if a cramp comes with swelling in one leg, muscle weakness, twitching, numbness, or visible loss of muscle bulk; if so, see a doctor. This is not meant to frighten you. Night cramps are usually manageable, and recognising the signs means you can act quickly if something does not feel right.

Go to A&E or call 999 if:

• One leg becomes painful, with swelling, redness, warmth, or a change in skin colour. This can be a deep vein thrombosis (DVT) and is a medical emergency, not a cramp. In pregnancy, sudden, one-sided calf pain with swelling needs urgent review.

Contact your GP or call 111 if you notice:

• Cramps that are frequent, severe, worsening, or wrecking your sleep
• A single cramp lasting more than about ten minutes, or one that stretching will not ease.
• Muscle weakness, twitching, or visible loss of muscle bulk alongside the cramps
• Numbness, pins and needles, or electric-shock pains in the same leg
• Cramping calf pain brought on by walking and relieved by rest (this needs a circulation check)
• Cramps that started after a new medicine
• Known thyroid disease, diabetes, kidney or liver disease alongside new cramps

Key takeaways

• A cramp is an electrical event in your nerves. Dehydration, salt and magnesium do not cause it. Once you know that, the rest of the advice makes sense.
• Stretching the cramping muscle is the fastest way to ease it at the time. For a calf, pull your toes up towards your shin and hold.
• Magnesium, bananas, and tonic water don’t hold up in the research as remedies for cramps. The evidence points to nightly stretching before bed, staying active during the day, loose bedcovers, and a medication review.
• Pickle juice is not folklore. In a controlled trial, it beat water, most likely through a reflex in your throat rather than anything reaching the muscle.
• No study has found that a single stretch changes anything. Nightly stretching for six weeks reduced cramps by 1.2 per night in one randomised trial of 80 adults over 55. One trial, not a body of evidence, and worth doing anyway since it is free and safe.
• Massage does not cure cramps. It helps with the sore, overloaded muscle around it and eases muscle tension.
• If you are in Milton Keynes and cramps are disrupting your sleep or your sport, give us a shout at Clinical Massage MK. Happy to talk about what is driving the pattern.

Frequently asked questions

What deficiency causes leg cramps at night?

For most people, none. Night cramps haven’t been reliably linked to low magnesium, potassium, calcium, or sodium, which is why blood tests usually come back normal. A Cochrane review found magnesium gave older adults roughly a fifth fewer cramps per week than a placebo. A diagnosed deficiency is different, and you need to see your GP to check it. Otherwise, you’re better off spending the money elsewhere.

What can I drink before bed to stop leg cramps?

Nothing you drink before bed reliably prevents cramps. What does work is drinking something sharp during a cramp. In a controlled trial, pickle juice relieved cramps about 37% faster than water, working through a reflex in the mouth and throat rather than anything reaching the muscle. Skip tonic water, which carries quinine’s dangers without a useful dose.

How many sessions will I need?

For persistent muscle tightness driving recurring cramps, a course of 6 sessions gives us time to see how you respond and make real progress. Many clients notice a shift within the first 3 to 4. We review as we go rather than committing you to a fixed block, and if massage is not the right answer for you, we will say so.

Why do I only get cramps at night and never in the day?

Your calf spends the night with the foot pointed, which is the position a muscle cramps from most easily, and sitting has usually shortened it through the day as well. Add in age, or a medication like an inhaler or a water tablet, and the odds tip further. Loose bedcovers, a pre-bed stretch, and more walking during the day all help.

Should I see a GP or a massage therapist first?

If your cramps come with swelling in one leg, weakness, numbness, muscle wasting, or they started soon after a new medicine, see your GP first. If they are ordinary night cramps or exercise cramps and you want help with the tightness and the pain, a massage is a good starting point.

More reading that might help

• – Clinical Massage in Milton Keynes, our main service page: https://www.clinicalmassagemk.co.uk/massage-treatments/
• – What Is Myofascial Release? Your Complete Guide: https://www.clinicalmassagemk.co.uk/what-is-myofascial-release/
• – How Long Does Sciatica Take to Heal?: https://www.clinicalmassagemk.co.uk/how-long-does-sciatica-take-to-heal/

References

1. Miller TM, Layzer RB (2005). Muscle cramps. Muscle & Nerve, 32:431-442.
2. Bertolasi L, De Grandis D, Bongiovanni LG, et al. (1993). The influence of muscular lengthening on cramps. Annals of Neurology, 33(2):176-180.
3. Schwellnus MP, Drew N, Collins M (2011). Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping. British Journal of Sports Medicine, 45(8):650-656.
4. Garrison SR, Korownyk CS, Kolber MR, et al. (2020). Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews, CD009402.
5. Garrison SR, Dormuth CR, Morrow RL, et al. (2012). Nocturnal leg cramps and prescription use that precedes them. Archives of Internal Medicine, 172(2):120-126.
6. Hallegraeff JM, van der Schans CP, de Ruiter R, de Greef MHG (2012). Stretching before sleep reduces the frequency and severity of nocturnal leg cramps in older adults. Journal of Physiotherapy, 58(1):17-22.
7. Miller KC, Mack GW, Knight KL, et al. (2010). Reflex inhibition of electrically induced muscle cramps in hypohydrated humans. Medicine & Science in Sports & Exercise, 42(5):953-961.
8. Miller KC, Burne JA (2014). Golgi tendon organ reflex inhibition following manually applied acute static stretching—Journal of Sports Sciences, 32(15).
9. Panza G, et al. (2017). Acute passive static stretching and cramp threshold frequency. Journal of Athletic Training, 52(10):918-924.
10. Miller KC, Harsen JD, Long BC (2018). Prophylactic stretching does not reduce cramp susceptibility. Muscle & Nerve, 57(3):473-477.
11. Craighead DH, et al. (2017). Ingestion of transient receptor potential channel agonists attenuates exercise-induced muscle cramps. Muscle & Nerve, 56(3):379-385.
12. Parlak S, et al. (2024). The effect of massage on cramp frequency, cramp severity, and sleep quality of hemodialysis patients: a randomised controlled trial. Hemodialysis International.
13. Mastnardo D, et al. (2016). Intradialytic massage for leg cramps among hemodialysis patients: a pilot randomised controlled trial—International Journal of Therapeutic Massage and Bodywork.
14. Xu J, Saliba SA, Jaffri AH (2022). The Effects of Minimalist Shoes on Plantar Intrinsic Foot Muscle Size and Strength: A Systematic Review. International Journal of Sports Medicine, 44(5):320-328. DOI: 10.1055/a-1908-8867.
15. Sullivan SJ, et al. (1991). Effects of massage on alpha motoneuron excitability. Physical Therapy, 71(8):555.
16. Goldberg J, et al. (1992). The effect of two intensities of massage on H-reflex amplitude. Physical Therapy.
17. Jung AP, Bishop PA, Al-Nawwas A, Dale RB (2005). Influence of hydration and electrolyte supplementation on incidence and time to onset of exercise-associated muscle cramps. Journal of Athletic Training, 40(2):71-75.
18. Allen RE, Kirby KA (2012). Nocturnal leg cramps. American Family Physician, 86(4):350-355.

Summary

A muscle cramp is a sudden involuntary contraction caused by motor nerves firing in a runaway burst, not by dehydration or a mineral deficiency. Night leg cramps are linked to age, inactivity, sleeping with the foot pointed, and medications such as inhalers and diuretics rather than statins; exercise cramps are driven by fatigue and racing faster than trained. For prevention, one randomised trial of 80 adults over 55 found that nightly calf and hamstring stretching before bed reduced cramps by 1.2 per night after six weeks. Magnesium, potassium, calcium, tonic water and extra water are not supported, and single bouts of stretching have shown no effect either. At Clinical Massage MK in Milton Keynes, Pavol Fabry treats the muscle tightness and overload patterns behind recurring cramps using clinical massage, myofascial release and assisted stretching, with an outcome-based 6-session approach for persistent problems.