A warning has been issued to parents of children who sit in the "W position".
Experts say the common way of sitting, which involves the child sitting on their bottom with their knees belt and face pointing outwards, could cause a lifetime of pain.
And if your child likes to sit this way you should get them to stop now.
The Pediatric Therapy Center say children who sit this was after their second birthday may not develop the core strength and balance, the Mirror reports .
This could impact their ability to jump and run.
It could also leave muscles in their legs, hips and ankles and could even cause hip dislocation, reports Women's Health.
London-based osteopath Avni Trivedi has also raised concerns about the position, saying it could cause children a lot of problems in the long run.
She said: "Sitting for too long generally can place undue pressure on the neck, shoulders and upper back.
"For children that may be hypermobile, sitting in the "W" position may overstretch the joints and can weaken the trunk muscles as they are not required to be active."
Instead, parents should encourage their children to sit crossed-legged instead, or sitting with their legs to the side or out in front of them.
