You put them down on the rug and they set off. Not on all fours: seated, one leg bent underneath and the other stretched out in front, pushing with one heel and one hand, bottom sliding over the parquet, and in three seconds they were on the other side of the room. Then someone pointed it out to you. At the park, at the nursery, under a video: "doesn't it crawl?".
Here is the answer straight away. What your child is doing has a name in the scientific literature, going back more than fifty years, in English bottom shuffling. It affects between 7% and 22% of healthy children depending on how it is counted, it is the second most frequent way of moving after crawling, it has often already happened in the family, and these children walk on average less than a month later than the others.
What is worth looking at is not the mode. It is symmetry, muscle tone and, above all, the gaze and the first words. I will explain why, with the real numbers and their limits.
How to recognise it
The picture is fairly recognisable. The child sits steadily, which is how they move, but not necessarily earlier than the others: in the 2026 Japanese survey the age at which children sat without support did not differ between those who moved seated and those who did not. From sitting, they move by pushing with their hands and heels, keeping their bottom on the floor. They often dislike lying on their tummy and protest when you put them there. And when you lift them under the arms, instead of planting their feet they often keep their legs bent and raised, as if they were still sitting in mid-air.
The first systematic description dates to 1970, in Developmental Medicine and Child Neurology: a series of 30 children who were "otherwise normal" who moved seated, by shuffling, scooting or sliding. It must be taken for what it is: a case series, the lowest rung on the ladder of evidence, with no comparison group. But that is where everything starts.
How common it really is
There is one thing that almost no article in Italian explains, and it is needed to understand why you find such different figures: it depends on the question you ask. If you count the children for whom moving seated is the main way of getting from one place to another, you get one figure. If you ask parents whether the child has ever done it, you get a figure about three times larger.
| Study | What it measured | Share |
|---|---|---|
| Robson, 1984 (UK) | predominant strategy before walking | 9% |
| Størvold, 2013 (Norway) | strategy before walking | 7.1% |
| Fox, 2002 (UK) | seated movement reported by parents | 21.4% |
| Kalmar, 2026 (Japan) | seated movement observed between 6 and 18 months | 21.6% |
Robson's 1984 study remains the clearest on the full distribution: 82% crawled on all fours as the main means of moving before standing up, 9% moved seated, 1% shuffled on the belly, 1% rolled, and 7% had no form of movement before standing and walking. Yes: there is a 7% of children who one day simply stand up and walk, and they are the first to do so.
The Japanese 2026 survey of 241 children without developmental disorders found that 52 (21.6%) moved seated between 6 and 18 months, with a mean age of onset of 8.3 months (standard deviation 2.0).
The 21.4% comes from the most entertaining study in this literature: in 2002, in Archives of Disease in Childhood, three researchers tested the legend that the surname "Shufflebottom" derives from a dominant hereditary trait, by questionnaire comparing people who carry that surname with people called "Walker". No difference, either in frequency or in age at first step. The useful figure is that overall 21.4%, which the authors comment is higher than previously described.
Do they walk later? Yes, but less than you were told
That these children walk later is an old observation: as early as 1984, Robson was writing that those who move seated tend to walk much later than crawlers. But "much later" is a judgement, not a measurement.
The measurement came from Norway. Størvold's 2013 study used two sources: the large national MoBa cohort (47,515 children) and a regional sample collected specifically (636 children). This is what came out:
- half of the Norwegian children were walking alone at 13 months, a quarter at 12, three quarters at 14; the mean age was 13.1 months (standard deviation 1.91);
- the 84.5% used crawling on all fours as their strategy before walking, 7.1% moved seated;
- crawlers started walking 0.9 months before those who moved seated (95% CI: 0.32-1.49; p < 0.05).
Stop on that number. Zero point nine months: twenty-seven days. It is a statistically significant difference, meaning real rather than noise, but it is less than a month out of a milestone that in healthy children is spread over nine full months: the World Health Organization window for independent walking runs from 8.2 to 17.6 months. Twenty-seven days inside a nine-month window is not a delay. It is a nuance.
Two limitations, stated in full. The Norwegian study drew on two different sources, one enormous and one small, and the published percentages are not broken down by one or the other: the comparison is solid in direction, less so in the decimal detail. And there is no reliable estimate of the absolute mean age of walking in children who move seated alone. Where the data is missing, we prefer to tell you so.
The complete windows, milestone by milestone, are in Not crawling and not walking: the real windows for motor milestones.
Crawling is not a required step
Here the hidden premise of the question "doesn't it crawl?" falls apart. The premise is that crawling is a required step. It is not.
In the World Health Organization study of 816 healthy children followed in Ghana, India, Norway, Oman and the United States, about 90% reached five of the six motor milestones following a common sequence, and 4.3% never showed crawling on all fours. Not late: never. It is the only one of the six milestones that a share of perfectly normal children skip entirely.
A caveat on how to read that number, because it is easy to misread it: the 4.3% is calculated across all the children in the cohort, not only across those who move seated. How many of them crawl anyway no one has measured. In fact, in the 2026 Japanese survey, the ages at which shuffling, crawling and sitting appeared did not differ between those who moved seated and those who did not.
Even the lists used for developmental surveillance have moved in this direction: in the review published in Pediatrics in 2022, the expert group convened by the American Academy of Pediatrics decided to keep only the milestones that at least 75% of children reach by a given check-up age, cutting the previous lists by 26.4%, to discourage the "let us wait and see" attitude.
And the paths really are many: a 2023 study followed 30 children at home in the two months before their first step, finding enormous variability in the ways they practised, and concluding that children reach walking by many distinct routes, regardless of the age at which they get there.
What crawling is and what it is not is covered in Crawling: when it starts, and what it means if it does not come.
Family: ask the grandparents
There is a question worth asking your mum and your mother-in-law: "how did I move around as a little one?". Very often the answer is the same thing.
It is the most consistent observation in this literature, even though no one has ever quantified it in the general population. In Lundberg's prospective study of 78 children with a marked motor delay but a normal neurological examination, among the factors pointing to a normal outcome were precisely the family history of seated movement, a pregnancy and birth without events, and seated movement itself, present in 51% of the 65 children who were still late walkers at the final check: over-represented, yes, and largely harmless.
The second finding comes from a Japanese study from 2021 of 48 children who moved seated: a family history of seated movement was present in 39% of those who did not subsequently receive a diagnosis of autism spectrum disorder, against 10% of those who did. I come back to that study shortly, because it has to be read carefully.
What these children miss out on
There is one concrete aspect, and it is not walking: it is time on the tummy.
A child who moves seated spends little time prone. The authors of the 2026 Japanese survey put this in their conclusions as a hypothesis, and I report it as such: seated movement could reduce the opportunities for full-body prone activity and therefore overall physical activity. It is a concern of the authors, not a measured result: that study did not compare the physical activity of the two groups.
It is worth knowing, however, what the research says about tummy time, because it is one of the few things you can act on. The systematic review published in Pediatrics in 2020, which gathered 16 studies and 4,237 children in eight countries, found tummy time associated with better gross motor development, a lower BMI-z score, prevention of brachycephaly, and the ability to move from prone, supine, crawling and rolling. But, and this is the honest part, the association with walking, standing and sitting was found to be indeterminate, and the authors point out that almost all the studies were observational, with a high risk of bias.
In plain terms: offer them tummy time because it is a motor experience they are taking away from themselves, not because you were promised it will make them walk sooner. No one can promise you that. If they protest as soon as you turn them over, and many of these children do, the strategies that work are in Tummy time: how to do it for real (and what to do if they cry).
And one thing that is not needed: putting your hands on them to teach them to crawl. None of the studies I have cited measured crawling training, and none shows that it brings walking forward.
When it does need looking at
Now the serious part, and I will write it plainly.
Moving seated is benign in the great majority of cases, but it is not an automatic pass. In 1971 Robson and Mac Keith published a paper whose title says it all: "Shufflers with spastic diplegic cerebral palsy: a confusing clinical picture". Some children with a form of cerebral palsy move seated just like healthy children, and can be mistaken for them. That is why the mode of movement, on its own, is never enough either to reassure or to alarm.
Asymmetry. In the Italian prospective study by Bottos of 424 children (270 survivors of neonatal intensive care and 154 controls without perinatal complications), asymmetry was found to be one of the most important factors in determining the movement strategy. And in an Italian study of 50 children videorecorded in the first weeks of walking, asymmetries of gait were correlated with asymmetries already observable in the earlier movement. Watch whether they always use only the same hand to push, whether one leg stays behind, whether they always turn the same way, whether one hand stays clenched in a fist.
Muscle tone. The 2013 clinical report of the American Academy of Pediatrics on motor delays focuses precisely on tone, and distinguishes two directions: with increased tone the suggested investigation is brain MRI; with reduced tone, a blood test for creatine kinase. The same document suggests formal developmental screening at the 9, 18, 30 and 48 month visits. And in a study of 43 children with benign congenital hypotonia, all referred for a motor delay in the first year, seated movement was present in 19%: hypotonia and seated movement can coexist, and it is the hypotonia that needs assessing.
Gaze and words. I return to the Japanese study of 48 children, and I ask you to read it with me, because it is very easy to be frightened by it. In that group, 20 children out of 48 (42%) received a diagnosis of autism spectrum disorder at follow-up. That 42% is not the probability for your child: those children had already been taken to a developmental centre, which means someone had already asked a question about them. It is a selected sample, and generalising it to the population would be wrong.
The really useful part is something else: gross motor development in the first year did not distinguish the two groups. What separated them was poor eye contact at the first consultation and delayed first words, both significantly more frequent in those who later received the diagnosis. The authors' conclusion is the same as the one we give you: in a child who moves seated, attention goes to social and communicative functions, not to the legs.
A last note of perspective. In the systematic review published in JAMA Pediatrics in 2017, cerebral palsy affects 1 in 500 births, and the diagnosis, historically made between 12 and 24 months, can now come before 6 months of corrected age. The tools that allow this are clinical assessments, not things to do at home watching the child on the rug: before 5 months of corrected age the most predictive are term-age MRI (sensitivity 86-89%), the assessment of General Movements according to Prechtl (98%) and the Hammersmith neurological examination (90%); after 5 months, MRI, the Hammersmith and the Developmental Assessment of Young Children. These are sensitivities in identifying a risk, not in confirming a diagnosis, and the review itself says to use these tools in combination with each other and with the clinical history, never on their own. The point is not that your child is at risk: it is that the tools to recognise early what needs recognising early already exist, and they do not involve counting how many times they crawl.
The red flags, with thresholds
These call for an assessment, not a wait:
- at 12 months they do not move in any way (not seated, not shuffling, not crawling, not rolling);
- at 9 completed months they cannot sit without support (this is the WHO's narrowest window: it closes at 9.2 months);
- at 18 months they do not walk alone (the WHO's 99th percentile is 17.6 months);
- constant asymmetry: one leg or one hand always behind, a fist always clenched, rotation always in the same direction;
- marked stiffness (legs crossing, toes pointing down when held upright) or marked floppiness (slipping through your hands, head flopping);
- no eye contact, no response to their own name, no words at 18 months;
- today, without waiting for the scheduled check-up: if they lose a skill they had already acquired;
- A&E: if they suddenly lose strength or movement, if a limb stops moving, if they suddenly become floppy and unresponsive.
Outside this list, a child who moves seated, uses both sides in the same way, looks for you with their eyes and tries to talk does not need to be corrected.
What a physiotherapist can do (and what they cannot)
Let us say it plainly: there is nothing to treat in a child who moves seated and is well. Anyone who offers you a course of sessions to "teach them to crawl" is selling a service, not a cure, and none of the studies cited here supports it.
What makes sense is smaller and more useful: watching them move, to answer three questions: do they use both sides in the same way? is their tone within the normal range? are the other areas, gaze and language included, progressing? Three yeses take the worry away; a no points you quickly towards whoever needs to see them.
With Ri-Hub Junior you start with a free 20-minute first consultation by video call with a physiotherapist on the Italian professional register who works with children and teenagers: you show us the child moving on the rug for a few minutes, which is all that is needed, and we tell you what we see. For children up to age 10 sessions last 50 minutes and cost 59,90 €.
Two limits, stated before rather than after. If any of the signs on the list above appears, the route is the paediatrician, straight away. And if there is a complex neurological or neuromuscular condition behind it, those pathways require in-person assessments and specialised centres: we do not follow them online.
In three lines
Moving seated on the bottom is a normal variant, the second most frequent after crawling, reported in between 7% and 22% of healthy children depending on how it is counted. These children walk on average less than a month later than the others, crawling is not a required step for everyone (4.3% of healthy children never do it), and it has often already happened in the family. Look at symmetry, tone, gaze and words: that is where the information lies, not in the way they cross the living room.
Sources
- WHO Motor Development Study: windows of achievement for six gross motor development milestones: Acta Paediatrica Supplement, 2006
- Prewalking locomotor movements and their use in predicting standing and walking: Child: Care, Health and Development, 1984
- Age for onset of walking and prewalking strategies: Early Human Development, 2013
- Locomotor strategies preceding independent walking: prospective study of neurological and language development in 424 cases: Developmental Medicine and Child Neurology, 1989
- Potential environmental factors influencing the occurrence of bottom shuffling in ordinary infants: Pediatrics International, 2026
- Do "Shufflebottoms" bottom shuffle?: Archives of Disease in Childhood, 2002
- Shuffling babies and autism spectrum disorder: Brain and Development, 2021
- Shuffling, hitching, scooting or sliding: some observations in 30 otherwise normal children: Developmental Medicine and Child Neurology, 1970
- Shufflers with spastic diplegic cerebral palsy: a confusing clinical picture: Developmental Medicine and Child Neurology, 1971
- Dissociated motor development: developmental patterns, clinical characteristics, causal factors and outcome, with special reference to late walking children: Neuropädiatrie, 1979
- Benign congenital hypotonia. A clinical study in 43 children: European Journal of Pediatrics, 1987
- Differences and variations in the patterns of early independent walking: Early Human Development, 1993
- Equifinality in infancy: The many paths to walking: Developmental Psychobiology, 2023
- Motor delays: early identification and evaluation: Pediatrics, 2013
- Early, Accurate Diagnosis and Early Intervention in Cerebral Palsy: Advances in Diagnosis and Treatment: JAMA Pediatrics, 2017
- Tummy Time and Infant Health Outcomes: A Systematic Review: Pediatrics, 2020
- Evidence-Informed Milestones for Developmental Surveillance Tools: Pediatrics, 2022
Last source check: September 2026.
