Olympian Lee Merrien is challenging Guernsey children to move more using fitness trackers to monitor their activity.

The Health Improvement Commission has 200 of the activity trackers for use by schools, young and sports groups.

Runner Lee Merrien has launched a challenge at La Houguette primary school to promote them.

He put a class of 20 seven and eight year olds to the test to see if they could clock up more physical activity then him in 30 minutes.

La Houguette is monitoring the activities of all pupils in year 3 to 6 over three days this week.

Alun Williams from the Health Improvement Commission says it will provide meaningful data:

"In the La Hougette study that we are doing the children will be wearing them for two or three days, we then go back into the school and we report back class by class and we look at their levels of activity. What we normally see is that boys are a bit more active that girls and as they become older they become less active. That's what we would expect.

What we need to have is an accurate, objective measure of how active they are so then we can see if we introduce some interventions or initiatives they have a positive impact. So that is why we are doing the measurements.

It's important because we want to encourage the levels of activity both at school and outside school, and until we know accurately what the evidence base is, we need to know that so we see how that can impact on what schools do and what we can suggest to families that they might do to help people be more active"