Why is my child so flexible? Hypermobility in children

Children are naturally more flexible than adults, and some are much more flexible than others. Being "double-jointed" is usually nothing to worry about, and it can even be an advantage. For a small number of children, though, very flexible joints come with pain, tiredness or frequent sprains. Here's how to tell the difference, and what helps.

What is hypermobility?

Joint hypermobility means some joints move further than normal.¹ When many joints are affected, it's called generalised joint hypermobility.¹,² It's not an illness, just the way someone is put together.³

It's very common in young children. Girls, younger children and some ethnic groups tend to be more flexible, and it often runs in families.¹,² Most children become less flexible as they get older.²,³

Many hypermobile children have no symptoms at all.³,⁴ Extra flexibility can help in activities like dance and gymnastics.¹,² When flexibility does cause ongoing problems, such as pain, fatigue or repeated injuries, doctors may call it joint hypermobility syndrome or a hypermobility spectrum disorder.⁴

What causes it?

Ligaments are the tough bands that hold joints together. They're made partly of a protein called collagen. In children with hypermobility, the collagen is slightly different, so the ligaments are looser and let the joints move more.²,³,⁴

Problems seem to come less from the flexibility itself and more from weaker muscles, low muscle stamina and less control of joint movement.³ That's good news, because muscle strength and control can be trained.

Signs and symptoms

Your child may be able to bend their thumbs, elbows or knees further back than other children. Some reach milestones like sitting and crawling a little later.¹

If hypermobility is causing problems, you might notice:

• aches in the muscles and joints, often during or after activity¹,³
• getting tired easily, for example after a long walk¹,³
• clumsiness or falling over more than other children³
• frequent sprains, especially of the ankles²,³
• flat feet, where the feet roll in³
• poor balance or co-ordination⁴

Some children also have tummy or bladder problems, such as constipation.¹,⁴

What can help?

Keep active. Exercise is one of the most important things for a hypermobile child. Not moving enough leads to weak muscles and more injuries.¹ Normal activities like PE, play and dance should continue.³ Low-impact activities such as swimming and cycling are often more comfortable if your child has pain.²,³

You don't need to stop your child doing what they love. Instead, talk with your podiatrist or physiotherapist about which activities suit your child. Children with hypermobility are generally advised to avoid contact sports and activities where they can't control their body well, such as trampolining.¹

Build strength. Exercises that strengthen the muscles around the joints make them more stable and can ease pain.²,³ Yoga and Pilates can help build core strength.³

Pace activity. Avoid "boom and bust", where your child does a lot one day and then nothing for days because of pain. Spread activity across the day and the week, and build up gradually.¹,³

Supportive shoes. Shoes that are firm around the heel, with a sturdy, cushioned sole and laces or buckles, give the foot more support. Thin, floppy shoes such as thongs and slip-ons give little support.³

Orthoses. Some children benefit from orthoses (shoe inserts) recommended by a podiatrist.⁴

Easing aches. Warm baths or a wrapped hot water bottle can help, especially in the evening.³ Muscle aches for a day or two after activity are normal and usually ease as muscles get stronger.³ Ask your pharmacist or GP before giving pain relief medicine.

When to see a podiatrist

Most flexible children don't need treatment. It's worth getting your child checked if they:

• often complain of pain in their legs, feet or joints
• get tired much more quickly than other children
• keep spraining their ankles or falling over
• have flat feet that hurt, or wear their shoes unevenly
• are avoiding activities, or missing school, because of pain.¹

See your GP as well if many joints are affected or your child has other symptoms, such as ongoing tummy problems, so they can check for related conditions.¹

At Foot Ankle Lower Limb, we look at how your child stands, walks and balances, and check their footwear. We can suggest strengthening exercises, shoes and, where needed, orthoses, and refer to a physiotherapist or GP if that would help. To have your child's feet checked, book an appointment.

References

1. Sydney Children's Hospitals Network (2026). Joint hypermobility factsheet. https://www.schn.health.nsw.gov.au/fact-sheets/joint-hypermobility
2. The Royal Children's Hospital Melbourne (2007). Generalised joint hypermobility (Orthopaedic fact sheet 13). https://www.rch.org.au/uploadedFiles/Main/Content/ortho/factsheets/JOINT-HYPERMOBILITY.pdf
3. Cambridge University Hospitals NHS Foundation Trust (2024). Joint hypermobility: information for children and young people. https://www.cuh.nhs.uk/patient-information/joint-hypermobility-information-for-children-and-young-people/
4. NHS (2023). Joint hypermobility syndrome. https://www.nhs.uk/conditions/joint-hypermobility/

Reviewed by Andrew Schox, Podiatrist, BSc(Hons) PGradDipPod MPod. Last reviewed October 2026.