Many adults believe that modern children spend too much time glued to television and computer screens when they should be out climbing trees - but is this really true? The Children of the 90s are going to help researchers find out!

Thousands of children in this world-renowned research project will be asked to wear a tiny activity monitor - the size of a matchbox - which will record every move they make for a week.

This is one of the largest studies ever undertaken of children's activity levels, and it will provide invaluable information for research into child health.

The activity survey forms part of new Focus 11+ sessions to which all the Children of the 90s will be invited when they are eleven and a half. Amongst many other activities, the children will be able to see how their skeletons have changed, discover if they can believe what they see, and explore their feelings about friendships.

14,000 Children of the 90s have been helping researchers at ALSPAC (Avon Longitudinal Study of Parents and Children) since before they were born. They generously give their time to improve life for future generations and the ALSPAC team make sure Focus sessions are fun for everyone.

Focus 11+ sessions start on Wednesday 29 January at the Focus Centre in Bristol and will continue for nearly two years.