AUTISM and ADHD are neurodevelopmental conditions that affect people’s communication, attention and behaviour.
But scientists claim the conditions may also affect someone’s appearance – for example in the shape of their backside.
A more prominent bum may be common in people who have autism or attention deficit hyperactivity disorder (ADHD).
This usually doesn’t have anything to do with genetics or body shape.
Instead, it’s often linked to a common postural issue called an anterior pelvic tilt.
It means the pelvis is tilted forward instead of staying neutral, causing the lower back to arch and the stomach to protrude.
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This sort of posture can also cause someone’s bum to stick out, creating what some people might refer to as a “duck butt.”
While anyone can have an anterior pelvic tilt, it’s common in children with autism or ADHD.
Autism affects how people socialise, communicate and interact with the world. It’s not a condition that needs to be ‘cured’.
Autistic people may find socialising confusing or tiring, become overwhelmed in loud or crowded places and crave order and routine.
Meanwhile, ADHD affects people’s behaviour and concentration, causing inattention, hyperactivity and problems with impulse control.
We tend to think about these conditions affecting how people behave – and in most cases, this is where traits of autism and ADHD show up.
But some studies have sought to find clues in the conditions in the appearance of people’s bodies and how they move.
Previous research has suggested some children with autism may have an “odd gait” – meaning they walk on the balls of their feet, or with their feet turned inwards or outwards.
A study published by scientists at the Poznan University of Medical Sciences in Poland in 2025 suggested children with autism had “a tendency to deviate more from normative body posture”.
Researchers observed 28 boys aged six to 17 with the condition, observing “shoulder protraction” and an anterior pelvic tilt in many.
It should be noted that this is an observational study, so we can’t draw any conclusions about autism causing changes in someone’s posture – only that the two are linked.
The study sample is also quite small.
In 2018, researchers from the Scientific Institute for Research, Hospitalisation and Healthcare in Italy – lead by Emilia Biffi – observed the gaits of children with autism.
Their study – published in the journal Frontiers in Psychology – used 3D motion analysis while children walked on a treadmill in a virtual reality simulator to compare how youngsters with and without autism moved.
What is autism?
Autism spectrum disorder (ASD) is an incurable, lifelong developmental condition that affects how people perceive the world and interact with others.
It affects around one in 100 people in the UK and is three to four times more common in boys than in girls.
Many people with ASD find it hard to understand other people’s feelings and emotions, and they may have difficulty holding conversations.
When they are young, their language development may take longer and they can struggle to use facial expressions, using gestures to communicate instead.
They may also find it hard to connect with other people and to hold eye contact with unfamiliar individuals.
Many children with ASD like to follow a routine, and changes to this can cause distress.
High functioning autism is an informal term some people use to describe those on the autism spectrum disorder.
This allowed the team to measure the joint angles of their pelvis, hip, knees, and ankles as they walked normally, as well as when sudden speed changes were introduced.
Researchers compared their observations to the gait of school-aged children without the condition.
They found that children with autism tended to walk with a more forward-tilted pelvis.
They also didn’t push off with their ankles as strongly when walking, and their hips were bent more forward than usual.
Researchers said these unusual walking patterns could lead to physical problems like lower back, hip, or knee pain, and make activities involving balance or quick movements harder.
The 9 ‘hidden’ signs of ADHD in adults
ADHD has long been associated with naughty schoolkids who cannot sit still in class.
And that is part of it. Fidgeting, daydreaming and getting easily distracted are all symptoms of the behavioural condition, which is why it is often spotted in children.
However, attention deficit hyperactivity disorder is far more complex than simply having trouble focusing.
Henry Shelford, CEO and co-founder of ADHD UK, says: “If it isn’t debilitating, it isn’t ADHD.”
In recent years, social media has given rise to trends which conflate specific personality traits or single behaviours with ADHD.
You might be thinking, ‘I’m always losing my keys, forgetting birthdays and I can never concentrate at work — I must have ADHD’. But it’s not as simple as that.
Though these may all point to the condition, Dr Elena Touroni, a consultant psychologist and co-founder of The Chelsea Psychology Clinic, says: “The key distinction lies in how much a behaviour impacts a person’s daily life.
“Genuine ADHD symptoms affect multiple areas of life – work, relationships and emotional wellbeing – whereas personality traits are typically context-dependent and less disruptive.”
ADHD UK’s Henry, who has the condition himself, adds: “Having ADHD is hard. One in ten men with ADHD and one in four women with ADHD will at some point try to take their own lives.”
So how can ADHD manifest in someone’s life? While hyperactivity is a common indicator, here are nine other subtle signs:
- Time blindness – losing track of time, underestimating how long tasks will take, regularly being late or excessively early
- Lack of organisation – a messy home, frequently misplacing items, forgetting deadlines
- Hyperfocus – becoming deeply engrossed in activities for hours
- Procrastination – feeling overwhelmed by to-do lists and struggling to determine what needs your attention first so focusing on less important tasks
- Heightened emotions – emotional struggles can manifest in angry outbursts, feeling flooded with joy or shutting down because you feel too much at once
- Being a ‘yes man’ – agreeing to new projects at work or dinner dates with friends when you’re already busy (a desire to please)
- Impatience – interrupting people mid-conversation, finding it painful to stand in a queue, being overly-chatty
- Restlessness – tapping, pacing, fidgeting or feeling restless on the inside
- Easily distracted – by external things, like noises, or internal things like thoughts
A forward pelvic tilt can throw off the body’s alignment, putting extra strain on the lower back, hips, and knees, causing pain or balance issues over time.
Research has also looked into the link between gait differences and ADHD.
A 2017 study from Japan looked at how nine and ten-year-old boys with ADHD walked compared to boys without it, using cameras that measured body movements in detail.
The researchers found that boys with ADHD had a more forward-tilted pelvis – about 4.5 degrees more on average – along with faster steps.
The tilt of their pelvis was strongly linked to their hyperactive and impulsive symptoms, they added.
“Our kinematic findings could have potential implications for evaluating the body movement in boys with ADHD,” the Japanese team wrote in the journal PLoS One.
Do gait differences need to be treated?
One reason children with autism and ADHD could develop an anterior pelvic tilt is because they may have low muscle tone, which can leave the core and glutes too weak to keep the pelvis properly aligned.
Sitting for long periods or repeating movements like toe walking can also tighten their hip flexors and lower back, pushing the pelvis even further out of position.
On top of that, many children with autism or ADHD can struggle with balance, coordination and body awareness, making it harder to maintain proper posture while standing or moving.
Nicole Rinehart, a Professor of clinical psychology and director of the neurodevelopment program at Monash University, explained that gait differences in autistic people might be caused by “differences in brain development”.
Areas such as the basal ganglia – which is responsible for making walking effortless, smooth and automatic – and the cerebellum, which controls and coordinates movement, may develop differently in people with autism, the expert said.
Writing in The Conversation, Prof Rinehart said: “While some researchers have suggested that autistic gait occurs due to delayed development, we now know gait differences persist across the lifespan.
“Some differences actually become clearer with age.”
Some people with gait differences may also have more difficulties with language and cognition.
In some cases, these signs can indicate that an autistic person is experiencing “sensory or cognitive overload” and might need some “extra support or a break” in that moment, the expert said.
Differences in the way autistic people walk don’t necessarily need to be treated, she added.
Prof Rinehart noted: “Some autistic people might have subtle gait differences that are observable during testing.
“But if these differences don’t impact a person’s ability to participate in everyday life, they don’t require support.”
But some may be at increased risk of falls, have difficulty participating in sports or other physical activities, or may get pain in their legs or back from the way they walk.
In these cases, children may benefit from some additional support, whether that be from a clinic, at school, or in their local communities.
“Our community-based intervention studies show autistic children’s movement abilities can improve after engaging in community-based interventions, such as sports or dance,” Prof Rinehart said.
“Community-based support models empower autistic children to have agency in how they move, rather than seeing different ways of moving as a problem to be fixed.”
The key characteristics of autism – and why they go unnoticed
MODEL Christine McGuinness was a “recluse” for eight years and only left the house at 3am.
Springwatch presenter Chris Packham says it makes him a “task-centric workaholic who sees problems in everything he does”.
And recently, Bella Ramsey revealed they were diagnosed after struggling to wear thermals on the set of The Last of Us.
But what exactly is autism and why does it seem so different in everyone?
Leanne Cooper-Brown, neurodevelopmental lead at Clinical Partners, tells Sun Health: “Autism is considered a spectrum, so not all people share the same traits.
“Whereas we used to think of autism as a linear line, we have come to realise that terms such as ‘high’ and ‘low’ functioning or definitions of ‘mild’, ‘moderate’ or ‘severe’ aren’t helpful and can be misleading.
“Nowadays, we think of autism in terms of the strengths and needs of the individual, which can change over time depending on their environment and support network.”
About 700,000 people in the UK are thought to have autism – that’s one in 100.
But research by University College London suggests that number could be twice as high, as many people remain undiagnosed.
Cases are on the rise though. Figures released last year showed a 175 per cent increase from 2011 to 2022.
Dr Selina Warlow, clinical psychologist and owner of The Nook Neurodevelopmental Clinic, says: “Conversation around neurodiversity is becoming normalised, and that’s so positive to see. But more awareness is needed.
“Receiving a diagnosis can open access to expert resources that support autistic people to thrive in society.”
Autism has long been associated with social difficulties, like problems maintaining conversations and forming relationships.
But research published in the journal Cell Press suggested that repetitive behaviours – like rocking or finger-flicking – and special interests – whether it’s TV shows or specific animals – are more indicative of an autism diagnosis.
Generally though, experts say the core characteristics include…
- Sensitivity – autistic people can be much more or less sensitive to sights, sounds, textures, tastes and smells. For example, they find bright lights or crowded spaces overwhelming, Leanne says. They may also stand too close to others or need to move their whole body to look at something.
- Stimming – to manage this sensory overload, some people use repetitive movements or sounds. “This is called stimming, and includes rocking, tapping and hand-flapping,” Dr Warlow says. “Though it’s something everyone does to some extent, those with autism are likely to engage with it as a form of self-regulation.”
- Masking – this is a strategy used by some autistic people, consciously or not, to match neurotypical people, Dr Warlow says. “It’s a way of hiding your true characteristics, and could involve copying facial expressions, planning conversations in advance, or holding in ‘stimming’ – swapping hand clapping with playing with a pen, for example,” she adds.
- Burnout – this is a state of physical, mental and emotional exhaustion and is a common feature in autism. “Being extremely tired, both mentally and physically, can be associated with the act of masking for a long period of time, or sensory or social overload,” Dr Warlow says. “Symptoms of autistic burnout include social withdrawal, reduced performance and increased sensitivity.”
- Social struggles – socialising can be confusing or tiring for autistic people. They often find it hard to understand what others are thinking or feeling, making it challenging to make friends. Leanne says: “In adults, autism may present as difficulties with interpreting social cues such as understanding body language or sarcasm, struggling to express emotions or preferring to be alone. This can impact relationships and work.”
- Routine – many of us have a fairly regular daily schedule. But for autistic people, this becomes a “very strong preference for routine”, Leanne says. This could be needing a daily timetable to know what is going to happen and when, or having rigid preferences about foods or clothing.
- Literal thinking – some autistic people have a literal view of language – like believing it’s actually “raining cats and dogs” or that someone really wants you to “break a leg”. Dr Warlow says: “This can result in confusion with figures of speech, irony or indirect requests. “For instance, being told to ‘pull your socks up’ might be understood literally, not as a motivational phrase.”
- Hyperfocus – often associated with ADHD, hyperfocusing is also common in autistic people. “It’s where you’re able to focus intensely on an activity and become absorbed to the point of forgetting about time,” Dr Warlow says. “This is useful in work or hobbies but can result in neglect of other aspects of life, such as food or rest.”
- Special interests – we all have hobbies and interests, but for autistic people, these are so compelling they often want to spend all their time learning about, thinking about or doing them. “Special interests could include anything from dinosaurs to superheroes, and gardening to music,” Dr Warlow says. “These usually begin in childhood, but can also form as an adult. “Chris Packham is an example of an autistic person who turned his childhood special interest in animals into a successful career, becoming one of the UK’s best-loved natural world TV presenters.