Skipping, cartwheels and handstands are activities that most 11- year-old girls take for granted, but for Charlotte Bean they have become impossible. "I feel left out of things sometimes," she says. "Sometimes I just have to sit and watch everyone else. But most of my friends understand, and don't get annoyed with me when I can't do things."

Charlotte has suffered intermittently from back pain since she was five years old. The cause has never been definitely identified, although her mother believes it may have sprung from early damage to ligaments in her back, which at the time went undetected.

"She began complaining of low back pain when she was in the infant school," says Mrs Bean. "Initially, I found it hard to take seriously. But after she had complained two or three times, I thought I'd better get it checked out. The GP got her to bend forwards and backwards, and looked at her spine, but felt it was nothing to worry about."

Despite this, Charlotte continued to complain occasionally that her back hurt. At nine, she tripped on a tree root and fell over backwards, which left her in severe pain. She had to stop PE at school, and give up the gym classes she used to enjoy. "Six months later, she bent to pick up the cat and said she felt as if a branch was breaking in her back," says Mrs Bean.

Charlotte was referred to a paediatrician who had her spine X-rayed, and carried out blood tests to check for infections. All the tests were negative, but the pain continued. She saw an orthopaedic surgeon, and was finally referred on to a paediatric physiotherapist.

Charlotte's school, Liss Junior School in Hampshire, have been helpful, allowing her to lie down on the floor in the library when she needs to, and administering drinks and biscuits with the painkilling medicine that she cannot take on an empty stomach.

Charlotte has been able to continue to swim over the past two years, but the almost constant back pain has put a damper on many activities. "I'm not allowed to wear heels," she says regretfully. Since March, she has had intensive physiotherapy, which appears to be working. "The physio seems to think that if she can keep up the gym and the games and the exercises, she'll be able to achieve a level of fitness to keep the pain away," says Mrs Bean.