It is half past two in the morning. A scream, the kind that pulls you out of bed before you are even awake. You find him sitting up, rigid, holding his leg, unable even to tell you what is happening. You touch his calf: it is hard as a stone, and under your fingers you feel the muscle pulled tight like a rope. The foot is turned with the toes pointing down. It lasts a minute, perhaps two. Then it lets go, he cries a little more and falls back asleep. You do not.
The short answer: that is a muscle cramp, and the only thing that stops it is to stretch the calf: knee straight, tip of the foot pulled towards the shin.
The long answer is more interesting, because on this subject there is much more confidence than the data allow.
What a cramp is, exactly
A cramp is an involuntary, sustained and painful contraction of a muscle. Three features define it, and you can recognise them in the dark: it lasts from a few seconds to a few minutes, the muscle is visibly deformed and to the touch hard like a knot, and the pain is out of proportion to how briefly it lasts.
The detail that almost nobody explains is where it starts. Not in the muscle: the cramp originates from dysregulated signals of the nervous system, which order the contraction and do not say to stop. The muscle is the executor, not the culprit. And this is why the only manoeuvre that works is mechanical, stretching it, and not chemical.
This also explains why the sequence is always the same: contraction, sharp pain, release, and then a residual soreness that stays for a while. In the largest paediatric series we have, soreness after the episode affected 30.8% of the children who had had cramps (57 out of 185) and lasted on average 33 minutes (with an extreme case of a whole day).
The difference from growing pains, which is what you need
The two conditions are constantly confused, and they change both what you do at night and what you need to look at.
The cramp: a single muscle, almost always one leg only (in the paediatric series it was one leg in 98.9% of cases), with the foot involved in 18.9%. The muscle can be seen and felt to be hard. The pain is violent and brief: an average duration of 1.7 minutes. The child is clearly awake and knows where it hurts.
Growing pains: a deep, dull pain that the child cannot locate well, almost always in both legs (in an Italian series of 30 children followed for a year they were bilateral in 80% of cases), and with no contraction to feel. The literature says little about how long the episode lasts; what is described is that it calms with massage (in the same series in 95% of cases) and that, in the classic picture, nothing remains by the morning. If this is the picture you recognise, the right place is the dedicated article: growing pains, what they really are.
And then there is the strongest discriminator: age. In the series of 2,527 children, night cramps were not recorded in any child under 8 years old, while growing pains are very common much earlier: in an Australian sample of 1,445 children aged 4 to 6, 36.9% had suffered from them. It is not a law of nature (a 5-year-old can have a cramp), but if your child is 4 and wakes screaming because of his legs, you are probably looking at something else.
How common they are (and how little we know)
Here I have to be honest, because this is the point where almost all the pages you find online pretend not to notice.
The reference figure is a 1999 study: the records of 2,527 healthy children followed in a clinic were reviewed, looking for night cramps in the previous twelve months. 185 had them, that is 7.3%. None under 8 years old. The incidence increased at 12 years and peaked between 16 and 18. The frequency, for those who had them, was very low: 81.6% had one to four episodes a year.
That series is, in practice, the backbone of everything read about night cramps in children: a retrospective review of records, from a single centre, more than twenty-five years ago, plus a summary article from the same group. No randomised trial in children, no Italian estimate, no consensus on how the episode is defined.
To give you a sense of the gap: the Cochrane review of 2021 that searched for all the non-drug therapies tested for at least four weeks on lower limb cramps, in any group of people except pregnant women, found in total three studies with 201 participants, all aged 50 and over.
So when someone tells you with certainty what to give your child for cramps, they are telling you something that nobody has ever measured in children.
The relief that really works
This is the only part on which the literature agrees: you stretch the muscle that has contracted. It is the symptomatic treatment indicated for calf cramps in paediatric age, and what the reviews on exercise cramps call gentle static stretching until the symptoms ease.
How to do it, in practice. With the child lying on his back:
- With one hand hold the knee straight, pressing just above the kneecap. This is the step almost everyone skips and it is the one that matters: with the knee bent the calf does not lengthen.
- With the other hand take the foot and push the tip towards the shin, firmly but gradually, without jerks.
- Hold until the muscle releases under your fingers: usually twenty to thirty seconds. If after a minute it is still contracted, release for a moment and start again.
- Then massage with the flat of your hand and, if he is up for it, have him walk a few steps.
If the cramp is in the foot or the toes, the gesture is the same: take the toes and pull them towards the shin.
What the literature indicates to stop the episode is stretching, and that is all: there is nothing studied in children on ice or heat, so do not use them instead of stretching. And kneading the muscle while it is still contracted, hoping it will loosen, only wastes time: what releases the contraction is stretching.
The remedies that circulate: what the evidence says
Magnesium
It is the first thing you will be advised to try, by anyone. And the evidence, in adults, is disappointing.
The Cochrane review of 2020 gathered eleven randomised trials involving 735 people. In adults with idiopathic cramps (average age between 61.6 and 69.3 years) the differences from placebo were small and not statistically significant: the difference in the number of cramps per week after four weeks was -0.18 (95% confidence interval: from -0.84 to 0.49). The percentage of people with at least a 25% reduction in episodes was identical in the two groups (risk ratio 1.04; from 0.84 to 1.29), and on this point the certainty of the evidence is high. The authors' conclusion: magnesium is unlikely to offer clinically significant prophylaxis to older people with cramps.
The other side, for honesty: a double-blind randomised trial from 2021, conducted in Ukraine on adults with night cramps (175 completed the 60-day protocol), found a real but small difference in favour of a magnesium oxide formulation (3.4 fewer episodes compared with 2.6 on placebo, p = 0.01). Look carefully at those two numbers: even those who took the sham capsule improved almost as much.
And in children? Among the populations of the eleven Cochrane studies (pregnancy, older people with idiopathic cramps, liver cirrhosis), there is no paediatric group. Oral magnesium, moreover, is not harmless: in the studies analysed, minor adverse events, mainly gastrointestinal such as diarrhoea, affected from 11% to 37% of those taking it. Before giving it to a child, the question should go to the paediatrician.
Hydration and mineral salts
The idea that a cramp is the sign of a dehydrated child is the most entrenched, and it is the one with the most fragile foundations.
The most cited review on the topic weighed, with explicit criteria, the evidence for the "dehydration" and "electrolyte depletion" hypotheses. The result: they rest on anecdotal observations, on case series totalling 18 cases and on a single small case-control study with 10 people. On the other side of the scale, four prospective cohort studies do not support them. The hypothesis that gathers the most data is another one: a temporary alteration of neuromuscular control, that is the disorder of signals discussed above.
The limit to declare: that literature concerns exercise cramps, not idiopathic night cramps. But it is the best that exists on the hypothesis "drinks too little", and a 2022 review draws the practical consequence: generic advice such as drink more is probably less useful than looking at the individual case.
This does not mean your child should drink less. It means that if he already drinks normally and the cramps continue, it is not your failure.
Evening stretching
It is the remedy with the most theoretical sense, and the results are contradictory even in adults.
In favour: a randomised trial on 80 adults over 55 who stretched their calves and hamstrings every evening before sleeping, for six weeks, measured 1.2 fewer cramps per night (from 0.6 to 1.8) and a pain level lower by 1.3 centimetres on a scale of 10.
Against: an English randomised trial on 191 adults who were taking quinine for night cramps, in 28 general practices, found no difference in either the number or the severity of cramps at twelve weeks, and concludes that calf stretches are not effective.
The Cochrane review of 2021 weighs those studies and remains cautious: calf and hamstring stretching for six weeks may reduce the intensity of night cramps from age 55 upwards (mean difference -1.30 out of 10; low certainty), but that figure comes entirely from the single study of 80 people mentioned above, and on frequency the uncertainty is very high; calf stretching alone for twelve weeks, against a sham stretch, made no difference.
In short: in children it has never been tested, and in those over 55 the benefit is at most modest. But in the three Cochrane studies nobody reported side effects, and it costs nothing. Do it, if it is not a burden, without expecting a switch to flip.
When it is not a cramp
Before getting to the red flags, two look-alikes worth knowing.
Restless legs syndrome is not pain: it is an irresistible urge to move the legs, which appears when sitting still in the evening and passes when you move. It is the opposite of a cramp, which does not pass by moving but by stretching. In a population study of 10,523 families in the United States and the United Kingdom, the defined form affected 1.9% of children aged 8 to 11 and 2.0% of those aged 12 to 17. One detail says it all: the questions in that study were built precisely to exclude cramps from the count.
And growing pains, discussed above: a label much more fragile than it seems, since a 2022 review in Pediatrics went through 145 studies and found "extremely poor" consensus on what this diagnosis is. A Turkish study of 4,565 boys and girls aged 9 to 18 measured both conditions in the same population: restless legs in 4.2% per year, growing pains in 3.1%, and a true overlap in just 12 young people out of 4,565.
⚠️ The red flags: when not to wait
A cramp has a precise course: a few minutes, then it is over, and on average another half hour of soreness. Anything that falls outside this course is not a cramp and needs checking.
Today, with the paediatrician or in the emergency room:
- Fever together with the leg pain, even mild.
- Swelling, heat or redness of the calf or of a joint.
- The child does not put the foot down or refuses to bear weight.
Within a few days, with the paediatrician:
- The pain is still there the next morning. The practical threshold: soreness after a cramp lasts on average 33 minutes; if twelve hours later the leg still hurts, tonight's episode was not (only) a cramp.
- Limping, even slight, even only in the first hour of the morning. On limping the rule is stricter: you will find it here, the child who limps.
- The same leg, always the same spot, night after night for more than two or three weeks, with pain that passes well with ibuprofen. This is the classic picture of osteoid osteoma, a benign bone lesion: in a series of 50 children and adolescents with osteoid osteoma of the hip the night pain was present in 90% of cases and relief with anti-inflammatories in 88%, but the diagnosis came more than six months late in 43%. It is benign and resolves, but it has to be found.
- Under 8 years old. It is not impossible, but it falls outside the picture described in the literature: in that age range the alternatives are more likely than a cramp.
- Frequent episodes: more than a couple a week for several weeks. In paediatric age the norm is one to four episodes a year.
- Cramps that also affect arms, hands or abdomen, or come with weakness, difficulty climbing stairs, or dark urine after exertion. Most leg cramps are benign and self-limiting, but occasionally they signal a general disorder: this is where the paediatrician orders tests.
- The child has recently started a new medicine.
Outside these cases, blood tests and X-rays are not needed: investigations are carried out only when the history or the examination points to something specific.
What you can do, in practice
For the night: learn the stretching sequence now, not at half past two.
For the weeks: keep a minimal diary: date, which leg, how long it lasted, what he had done that day. Three lines on the phone. In a disorder where the normal frequency is a few episodes a year, knowing whether there have been two in six months or four in a week changes the whole conversation with the paediatrician. And it is the one thing no article can do for you.
If he plays football, basketball or volleyball, watch the loads: weeks of training suddenly doubled, new shoes, different pitches. It is not a proven explanation, but it is the only lever you can act on without risk.
When it makes sense to talk to a physiotherapist
Not for the cramp itself: that is resolved in two minutes with your own hands.
It makes sense when there is something else around the cramp: a boy who trains a lot and always has stiff calves, a pain that appears after the same sporting gesture, a load that has grown too fast, or simply the fact that you cannot tell whether what you see at night is a cramp, growing pains or something else. Watching him move, walk and rise onto his toes adds information that a description on the phone does not give.
What a physiotherapist does not do is replace the paediatrician when the red flags in this article are present: in those cases the first step is the medical visit, and we tell you that straight away.
With Ri-Hub Junior you can start with a free twenty-minute introductory consultation by video call with a physiotherapist on the Italian professional register who works with children and teenagers: you tell them what happens at night, the assessment is done together, and if the right place is not us, they tell you that during the call. For children up to 10 years old sessions last 50 minutes and cost 59,90 €; from 11 to 18 they are standard sessions at 29,90 €.
If the night cramps are yours and not your child's, the picture changes quite a lot (and the evidence is a little richer): night leg cramps in adults.
Sources
- Leg cramps in children: Clinical Pediatrics, 1997
- Nocturnal leg cramps in children: incidence and clinical characteristics: Journal of the National Medical Association, 1999
- Muscle Cramps: StatPearls, updated 2025
- Magnesium for skeletal muscle cramps: Cochrane Database of Systematic Reviews, 2020
- A randomized, double-blind, placebo-controlled, multicenter study assessing the efficacy of magnesium oxide monohydrate in the treatment of nocturnal leg cramps: Nutrition Journal, 2021
- Non-drug therapies for the secondary prevention of lower limb muscle cramps: Cochrane Database of Systematic Reviews, 2021
- Stretching before sleep reduces the frequency and severity of nocturnal leg cramps in older adults: a randomised trial: Journal of Physiotherapy, 2012
- Managing nocturnal leg cramps: calf-stretching exercises and cessation of quinine treatment: a factorial randomised controlled trial: British Journal of General Practice, 2005
- Cause of exercise associated muscle cramps (EAMC): altered neuromuscular control, dehydration or electrolyte depletion?: British Journal of Sports Medicine, 2009
- An Evidence-Based Review of the Pathophysiology, Treatment, and Prevention of Exercise-Associated Muscle Cramps: Journal of Athletic Training, 2022
- Restless legs syndrome: prevalence and impact in children and adolescents: the Peds REST study: Pediatrics, 2007
- Overlapping features of restless legs syndrome and growing pains in Turkish children and adolescents: Brain & Development, 2022
- Defining Growing Pains: A Scoping Review: Pediatrics, 2022
- Growing pains: a study of 30 cases and a review of the literature: Journal of Pediatric Orthopaedics, 2011
- Prevalence of "growing pains" in young children: The Journal of Pediatrics, 2004
- Osteoid Osteoma About the Hip in Children and Adolescents: Journal of Bone and Joint Surgery (Am), 2019
Last source check: September 2026.
