He spent a term at an inner-city school working with a class of 12-year-olds to try and improve their health and fitness in time for an end-of-term competition.

Here, he explains the major hurdles he overcame and how an increase in exercise had a positive effect on the class.

You can listen to the programmes on Radio 4 on 26, 27 and 28 February 2007 at 1100 GMT. Or you can listen again on the radio 4 website.

By Roger Black Former 400m Olympic and world silver medallist

I couldn't believe it when I was told that five years ago only a quarter of schools offered pupils two hours of PE a week.

It's easy to stand on the outside and say kids aren't as fit nowadays, but I wanted to go and see what was going on.

So I spent a term with a class of 12-13 year olds from Hurlingham and Chelsea school and changed their curriculum so they got to do more PE.

We also gave them a clear goal: to compete at an indoor athletics competition against two other schools in their area.

And we got some amazing results - but it was tough.

HOW YOU CAN GET INVOLVED The Youth Sport Trust says one of the biggest challenges in school sport is a shortage of adult volunteers By signing up, volunteers can help achieve the ambition of getting all young people participating in 4-5 hours of exercise a week Click here for more details

Hurlingham and Chelsea school is a typical inner city school. The kids are a pretty rowdy bunch.

The facilities were meagre too. They had two small gyms which were pretty old but more importantly they had no outdoor facilities. No grass, no playing fields at all.

However we managed to get the local council to cordon off an area in the park across the road. It seemed madness that they had this park so close and they weren't officially allowed to use it.

Before we went into the school the kids were getting one double lesson of PE a week on a Friday which was one hour 40 minutes.

We then added another half hour on Monday and Wednesday mornings, so they were doing physical exercise every other day and the benefits were seen by the whole school.

Teachers were saying they were much more attentive as a class and much more of a unit that term.

606 DEBATE: Is enough sport played at schools?

It was great to get some of the girls pushing themselves when they usually wouldn't even take part.

Hopefully the headmaster will change it now for the whole school. He felt that the class benefitted enormously.

What I wanted to teach them was it is not about winning and losing, it is about winning and learning.

It's not about creating Olympic champions for 2012. It's just about getting people doing some exercise Roger Black

They weren't going to win this competition that we organised for the end of term. They were up against one private school and one very sporty school.

But what I taught them was to give me 100%, walk away from the competition knowing that you gave it your best and then everything's fine.

They actually did that and I was really proud of them. That sort of thing is a lesson for life and hopefully I've got that through to them. More so than just getting fit.

Overall I would say school sport is undervalued.

The biggest impression that I have is that there are some kids who, if they don't any exercise at school, will never do any exercise throughout their lives. That's worrying.

It should be compulsory at school; you need to be creative and you need to have different forms of exercise but you need to get kids moving.

Let them experience team work and let them have a challenge. Let them learn to win and learn to lose. Not just playing games but giving them physical challenges.

Like Hurlingham and Chelsea school, I think physical exercise needs to be changed so that kids are doing it every other day.

That needs to come from the government and the schools and hopefully the Radio 4 campaign will encourage volunteers to come forward and help out too.

It's not about creating Olympic champions for 2012. It's just about getting people doing some exercise.

But the Olympics being hosted in London does provide an opportunity for kids to get excited about it and therefore get excited sport.