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Ri-Hub Junior

What Trainers to Buy for a Child: What Really Matters

Team Ri-Hub15 min lettura

Revisione clinica: Daniele Carretto, Fisioterapista (Albo 2019) · Pubblicato il 29 giugno 2026

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It happens in a shop or in front of a website, and it always ends the same way. Your child's foot goes onto a platform that photographs it, a coloured diagram of pressures appears, and someone explains that they roll inwards a little: they need a shoe with arch support and good cushioning. It costs 90 euros, and you will buy another two or three times a year because the foot keeps growing.

Here is the honest version straight away. The three things being sold to you (arch support, cushioning, a shoe chosen from the footprint) are the three things the evidence is weakest on. The three that really decide matters (length, width and the point where it bends) cost nothing, and nobody checks them for you. For a child who walks well and goes to school, the shoe does not cure anything: it protects and contains, and it should be chosen like clothing, that is, by size.

Here we are talking about children who already walk and go to school: for first steps the discussion is different, and it is in shoes for first steps: when they are really needed; the opposite route, that of thin soles, is in barefoot shoes for children: what the studies really say.

The shop's promises, and how well they hold up

Arch support and corrective shoes

This is the oldest promise and the most refuted. The study that counts dates from 1989 and nobody has yet overturned it: 129 children with flat feet documented on X-ray, randomised into four groups (no treatment, corrective orthopaedic shoes, a heel cup, custom insoles), and those assigned to a treatment wore it for at least three years. In the end all the groups had improved in a statistically significant way, including the children who had done nothing, and there was no difference at all between treated and untreated children.

The 2022 Cochrane review, covering 16 randomised studies and 1,058 children from 11 months to 19 years, reaches the same point in unusually blunt terms: in the absence of pain, expensive custom insoles for healthy children with flexible flat feet have no supporting evidence, and research on asymptomatic flat feet should be shelved.

This promise works because flat feet in children are very common and frightening. The German guideline sets it out like this: under six years, flexible flat feet are almost always physiological, present in 97% of 19-month-old children; at ten years, the persistent or progressive form affects about 4%, and fewer than 2% develop pain. And on prevention it does not recommend a technical shoe: it recommends informing parents, daily movement, a healthy weight, soft shoes that are long and wide enough as protection, and walking barefoot on uneven ground. The topic is covered in full in flat feet in children: when you really need to worry.

A word of caution on the opposite claim too: the 2022 meta-analysis on risk factors, which pooled 3,602 children with flat feet from 15 studies, links flat feet with the use of sports shoes (odds ratio 2.97), but these are cross-sectional studies, which do not demonstrate any causal relationship.

Cushioning and the shoe chosen from the footprint

One uncomfortable point needs to be made straight away: children are not in the cushioning studies. The evidence comes from adults who run, and even there it does not support the promises.

The 2022 Cochrane review on running shoes pooled 12 controlled studies and 11,240 adults. Neutral and cushioned shoes make little or no difference to injuries compared with minimalist ones (5 studies, 766 participants; relative risk 0.77, interval 0.59-1.01), and a soft sole compared with a hard sole (2 studies, 1,095 participants; 0.82, interval 0.61-1.10): in both cases the evidence is of low certainty.

The part that concerns the shop's platform is the other one. In the 3 studies of 7,203 participants in which the shoe was prescribed on the basis of static foot posture, the injury rate was the same as for those who received a shoe chosen without looking at the footprint (rate ratio 1.03, interval 0.94-1.13). This is the only comparison in the review with moderate certainty, that is, the most reliable one, even though it was done on military recruits, so it cannot be transferred automatically to an eight-year-old.

Finally, there is a trial that does find an effect, and it overturns the shop's slogan. 848 recreational runners were randomly given one of two prototypes identical except for the cushioning, followed for six months: those with the hard shoe were injured more often (hazard ratio 1.52, interval 1.07-2.16). But when stratified by body weight, the protective effect was seen in the lighter runners (1.80) and not in the heavier ones (1.23, not significant). Exactly the opposite of "they are robust, so they need more cushioning".

What really matters: the size

Here the data are abundant, consistent and embarrassing.

Study Who What emerged
Austria, 2009 858 preschool children, 1,579 feet Indoor shoes too short in 88.8% (of 808 assessed) and outdoor shoes in 69.4% (of 812); only 23.9% of the feet had a straight big toe
Spain, 2019 505 children aged 3-12 Shoe shorter than the foot in 33.3%; with the reference allowance, too short in 72.5% and too narrow in 66.7%
Review, 2018 18 studies on children, adults and older people Between 63% and 72% wore shoes that did not accommodate the length or width of the foot

In the Austrian study the link goes in one direction only: the shorter the shoe, the more the big toe was deviated sideways, with a significantly increased risk of a deviation of at least 4 degrees, and in 14.2% of the feet the deviation was already 10 degrees or more, in children who had not yet started school.

But beware of the wrong remedy. In a study of 100 six-year-olds, shoes that were too long and too wide were more common than those that were too short, and the longer and wider they were, the lower the arch. It is a cross-sectional association in a small sample, but it takes the force out of the idea of buying two sizes up "so they last".

Measuring the foot at home, in three minutes

You need an A4 sheet, a pencil and a ruler.

  1. Do it in the evening, after they have been playing: by the end of the day the foot is larger.
  2. Put the sheet against the wall. Your child stands on it, standing, weight on both feet, heel against the wall.
  3. With the pencil perpendicular to the sheet, mark in front of the longest toe, which is not always the big toe.
  4. Repeat with the other foot: they are almost never the same, and only the longer one counts from here on.
  5. Measure from the edge of the sheet to the mark and add 10 mm (the reference range is 5-15).

That number is the internal length the shoe needs to have, not the number on the box: from brand to brand the same number varies quite a lot. To check it, if the insole is removable, take it out and put the foot on top of it; if it is not, slide a piece of card of the calculated length all the way to the end, and it should lie flat without bending. The worst method is the one everybody uses, pressing a thumb on the toe with the shoe on: a child pulls their toes back as soon as you touch the shoe, and will never tell you it is too tight.

Width, which nobody checks

It is the forgotten parameter: the 2018 review calls for more attention to width in particular, and in the Spanish study 66.7% of the shoes were too narrow. The reference is about 10 mm more than the width of the forefoot, and the check is visual: the upper must not overhang the sole at the sides, and the big toe must not be pushed towards the other toes. Pointed, tapered trainers are a problem of shape, not size: you can go up a size as much as you like, the toe box stays triangular.

Bambina che pratica yoga in un ambiente interno sereno, focalizzandosi sul benessere e sulla consapevolezza.

Where it bends, and how much it weighs

Flexibility. Hold the shoe by the toe and the heel and bend it: it should bend under the toes, where the foot bends when it pushes off, not in the middle of the sole. Honesty about the evidence: the 2019 systematic review on sole flexibility, 4 studies, 262 participants aged 15 to 79 months, classes the evidence on individual characteristics as limited, and found peak plantar pressure generally lower with a stiff sole and higher with an ultra-flexible shoe. More flexible does not mean better on everything: the rule of bending under the toes is a sensible starting point, not a dogma.

Weight. Nobody has compared children in light shoes with children in heavy ones. There is, however, one interesting measure: 25 children of about 9.7 years walked at a free pace on a treadmill, barefoot and in a running shoe, and in the shoe their oxygen consumption was higher: 17.6 against 16.3 ml/kg/min, about 8% more. It does not isolate weight from the other effects of footwear, but it shows that wearing shoes costs energy: between two shoes that work equally well, choose the lighter one.

Finally, look at the heel counter: squeezed between two fingers it should resist. It does not need to be high above the ankle, however: there is no evidence that the ankle of a healthy child needs supporting.

Gym and everyday use: two shoes, not five

The international consensus built with 121 participants from among parents, healthcare professionals, researchers and industry players, which produced a shared classification of 14 types of footwear for children under six, reaches a sentence that holds afterwards too: one shoe is not right for every use. And the difference is practical more than biomechanical. The everyday shoe is worn for six to eight hours, gets rain and mud, has to be put on alone (with a strap or elastic until the child can tie laces) and should be bought roomy because by the end of the day the foot swells. The gym shoe lives in a bag, dry, and is used for one hour of jumping and changes of direction on a smooth floor: there the sole must not leave marks, and the fit needs to be more precise, because in a shoe that moves the foot slides around. A useful side effect: worn one hour a week, it lasts much longer.

How often to change them, and the myth of "they are still good"

The criterion is not wear. Children's shoes come to the end of their life because they become short, not because they break: in none of the studies seen was the problem worn soles; everywhere, it was length. When a shoe still looks new, it is usually because it is, and it is becoming small.

A checking interval backed by a study does not exist, and anyone who gives you a figure of once a month is giving it without evidence. What has been measured is that in the large majority of children the shoe is too short, and not through parental carelessness: the foot grows quietly and a child does not complain until it really hurts. The authors of the Spanish study indeed call for parents and teachers to be made aware of the periodic replacement of footwear. The remedy is to put the tape measure in the calendar: every two or three months for the youngest, every three or four at school age. This is prudence, not a finding.

On genuine wear, the sole that always wears down on the same side, there is a dedicated page: shoes worn down on one side: what sole wear really tells you.

Second-hand shoes

The honest answer is less drastic than what is heard around. Let us start with what we do not know: nobody has ever compared children in new shoes with children in used shoes. There is no study, so anyone who answers with certainty, in either direction, goes beyond the evidence.

We can, however, reason consistently. The classic argument against is that the shoe takes the shape of the foot of the person who wore it before and then imposes it on yours. But if three years of orthopaedic shoes built precisely to correct a foot did not change it more than it changed on its own, it is hardly credible that a few months of another child would deform the shoe enough to harm your child's foot. The footwear has less power than it is credited with, and this holds in both directions: it does not correct, and so it does not harm.

The real risk is banal: you inherit the size that is there, not the one that is needed. A shoe arrives, it fits "more or less", and it stays on the feet for three months, which is the same reason a new shoe bought in a hurry is risky. In practice, a used shoe is fine if it passes four checks:

  • The size, with the card or the insole. If it does not pass this, stop here.
  • The heel counter: if it has collapsed, the foot slides backwards.
  • The upper: it must not come out beyond the edge of the sole, a sign that the previous foot was already pushing it out.
  • The sole: even wear from left to right, no heel worn away on one side only.

On hygiene none of the studies cited here says anything: out of caution, choose a washable shoe, and do not share socks. This is not a reason to give up on second-hand shoes: it is a reason to wash them first.

Red flags: when the shoe is not the problem

Changing footwear will not solve these: you need the paediatrician. The thresholds are set out deliberately.

  • Pain in the foot or leg that lasts more than two weeks, wakes them at night, or is present at rest.
  • Limping that lasts more than three or four days.
  • Rigid flat foot: the arch does not appear when they rise onto their toes or sit down.
  • Clear asymmetry between the two feet: one flat and one not.
  • Walks consistently on their toes beyond the age of three.
  • Swelling, redness or heat in one spot on the foot, with or without fever.
  • They have lost something they used to do: no longer run, want to be carried.
  • Blisters or calluses always in the same place despite shoes of a verified size.

A flexible, symmetrical, painless flat foot at six is not on this list: it is statistical normality.

Getting followed, if needed

If your child has pain in their feet or calves after school, tires before the others, or you have bought three different pairs and the problem has stayed, the question is not which shoe to buy: it is where the problem comes from.

With Ri-Hub Junior you 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: they watch how the child walks and runs, test strength, ankle mobility and balance, and establish whether there is something to train. Up to age 10 sessions last 50 minutes and cost 59,90 €; from 11 to 18 the standard session applies at 29,90 €.

Two limits, stated before rather than after. If the red flags in the list above are present, the right place is the paediatrician, straight away. And complex neurological and neuromuscular conditions require in-person assessments and specialised centres: we do not follow those online.

In three lines

The features that cost the most (arch support, cushioning, a shoe chosen from the footprint) are the ones the evidence is weakest on, and in the healthy child they have never shown anything. The ones that matter cost nothing: ten millimetres in front of the longest toe, enough width, bending under the toes, low weight, with the tape measure in hand every two or three months. And second-hand shoes are not a problem in themselves: they become one only if they lead you to accept a size that is not your child's.

Sources

Sources last checked: September 2026.

Domande frequenti

What is the most important thing in a child's trainer?

The internal length, and it is not even a contest. In a study of 505 Spanish children aged 3 to 12, the shoe was internally shorter than the foot in 33.3% of cases, and using an adequate allowance of 5-15 mm in length as the reference it was too short in 72.5% and too narrow in 66.7%: only a third of the children had shoes in the right size. In an Austrian study of 858 preschool children, indoor shoes were too short in 88.8% of the 808 cases assessed and outdoor shoes in 69.4% of 812, and the shorter the shoe, the more the big toe was deviated sideways. Before the model, the brand and the technology, comes the centimetre in front of the toes.

Are shoes with arch support needed?

In a healthy child without pain, no: there is no evidence to support them. The clearest study dates from 1989 and it is still the one that holds: 129 children with flat feet randomised into four groups (no treatment, corrective orthopaedic shoes, a heel cup, custom insoles), and those assigned to a treatment wore it for at least three years. In the end all the groups had improved, including the children who had done nothing, and there was no difference between treated and untreated children. The 2022 Cochrane review, covering 16 studies and 1,058 children, reaches the same conclusion: in the absence of pain, custom insoles for healthy children with flexible flat feet have no supporting evidence.

How much space should there be in front of the toes?

The range used in the literature is 5-15 mm of extra length over the longer foot, and about 10 mm of width. In practice ten millimetres is a good rule: under five the margin disappears straight away, over fifteen the foot slides inside. Take care not to overdo it in the opposite direction: in a study of 100 six-year-olds, shoes that were too long and too wide were more common than shoes that were too short and tight, and the longer and wider the shoes, the lower the arch. It is a cross-sectional association, not proof of cause, but it takes the force out of the idea of buying two sizes up so that they last.

How often should a child's shoes be changed?

The criterion is not wear, it is the internal length: children's shoes become unusable because they are short, not because they are broken. No study has shown a checking interval, and anyone who gives you a precise figure is giving it without evidence: what has been measured is that most children in every published study wear shoes that are too short. Checking with a tape measure every two or three months is a prudent choice, not a finding. The authors of the Spanish study of 505 children explicitly conclude that parents and teachers need to be made aware of the need to replace school-age children's footwear periodically.

Does cushioning protect a child from injury?

There is no evidence that it does in children, and in adults the picture is weaker than advertising suggests. The 2022 Cochrane review of 12 controlled studies and 11,240 adults found that neutral and cushioned shoes make little or no difference to injuries compared with minimalist ones (5 studies, 766 participants), and that a soft sole makes little or no difference compared with a hard sole (2 studies, 1,095 participants), with low-certainty evidence. A trial of 848 recreational runners found a higher risk with hard shoes, but with a counterintuitive result: the protective effect of cushioning was seen in the lighter runners, not in the heavier ones. All of this concerns adults who run, not children who go to school.

Are second-hand shoes bad for the feet?

No study has ever compared children in new shoes with children in used shoes, so anyone who answers with certainty in either direction is going beyond the evidence. The argument one hears, that a shoe takes the shape of the foot of the person who wore it before, is however hard to reconcile with what we know: if three years of corrective orthopaedic shoes do not change a child's foot, it is hardly credible that a few months of another child would shape the shoe enough to harm yours. The real risk of second-hand shoes is a different and banal one: you inherit the size that is there, not the one that is needed. A shoe that has been worn little, is the right size, with a heel counter still firm and the sole worn evenly, is a reasonable choice.

Does one need a different shoe for the gym and for everyday use?

Yes, but for practical reasons more than biomechanical ones. An everyday shoe is worn for six to eight hours, is put on and taken off alone, and gets rain and mud; a gym shoe lives in a bag, stays dry and clean, and is needed for an hour of jumping and changes of direction on a wooden floor. The international consensus reached by 121 parents, healthcare professionals and industry players on 14 types of footwear reaches this conclusion: one shoe is not right for every use. That does not mean you need five pairs: two are enough, and the second lasts longer precisely because it is used less.

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