It is not every day that you walk into a primary school to find the teachers kitted out in tracksuits ready to play games in the PE hall.

Thankfully, the sign on the front door of Marley Grange National School in Rathfarnham, Dublin, offers an immediate explanation. "The school will be closed for in-service training," it says.

On a typical Monday morning, The 20 or so teachers at the school are being taught the revised physical education curriculum for primary level, and are throwing themselves into it with gusto.

After a session in the classroom where they go through some of the finer details of the curriculum - including aquatics and the importance of hygiene and water safety - they proceed to the school's PE hall to put theory into practice.

Things can get competitive here - one game, known as "Shamrocks and Leprechauns" - illustrates that no matter how old you get, winning during PE time is still important to some. The game requires two (adult) participants wearing luminous yellow bibs to chase the others for their pots of gold.

But the days of simply throwing a ball at children and getting them to play a game of soccer are long gone. The instructor for the day, Sean Gallagher, is constantly asking questions of his class, and explains the meaning of the various exercises throughout.

Afterwards, the teachers at the school will consider how to apply the different lessons to their own classes. For example, some exercises may need to be adapted to meet the specific requirements of students with special needs.

All this does not stop Gallagher from sounding a word of caution to his charges, however. "I just want you to remember one thing: you're adults," he says with a smile.

While the teachers' enthusiasm for the day is clear - the best way to learn is through direct experience, John Williams, the school principal, later explains - today's training also has a more serious undertone.

According to recent reports, obesity rates among Irish children have tripled over the last 10 years. Other studies suggest that the number of overweight people and incidence of diabetes in the State are near those of the US.

Eating larger portions, too much bread and fast-food meals, as well as the demise of the traditional "three meals a day" are all contributing factors to the increase in obesity rates here.

But while the exercises that students learn during PE class can be interlinked with other aspects of the primary curriculum, efforts made by schools will not be the only answer to the problem of childhood obesity.

Gallagher, who is assistant national co-ordinator for the primary curriculum support programme, underlines the importance of parental involvement.

"I don't think it is fair to say teachers have the cure to high levels of obesity . . . Parents have a huge role to play as well," he explains.

"Obesity is primarily down to two things: a lack of physical activity and eating too much. So we're saying to the child that their lifestyle is very important. This includes athletics and games, but healthy eating is important as well."

Differences in the quality of facilities available to primary schools here is something Gallagher is only too aware of as a result of his frequent visits to schools.

For example, teachers are being taught about aquatics - which can be particularly useful for children with special needs - but many do not have access to a local swimming pool to put their theory into practice.

"Every teacher we've encountered wants the best facilities for their students," he says. "The big picture is that we are going to have to have a joint effort to provide facilities."

This is something with which Williams, the school principal, wholeheartedly agrees.

Marley Grange has introduced a healthy-lunch policy at the school, he says, which encourages children not to have fizzy drinks and sweets for their lunch. Students at the school can also avail of an extra five-minute fruit break if they bring in a piece of fruit for their lunch.

"We are also getting children to examine their own exercise routine. It's amazing the number of children being driven to school every morning, even if they only live a few hundred yards away," he says. "Hopefully by the time they leave sixth class they will see exercise as important and healthy eating as important."

But without the necessary funding to get his students to the nearest swimming pool in Stillorgan, aquatics will have to remain an extra-curricular activity paid for by parents, Williams says.

"It is frustrating. Children with special needs - especially kids with a physical disability - thrive in a swimming pool. It improves their holistic development."

For their part, teachers are only too aware of the importance of physical education, and emphasise participation by all children in all activities, says John Carr, general secretary of the Irish National Teachers' Organisation.

When it comes to tackling childhood obesity, the revised curriculum is also "badly needed", he adds.

"Physical education has a vital contribution to make to the full development of the child and also in developing healthy attitudes to exercise and participation in sport which persist into adulthood," he believes. "Life-time attitudes to sport are formed at a very young age and it is essential that every child is encouraged to enjoy physical education."

But the ultimate success of programmes aimed at tackling childhood obesity may be put at risk unless the amount of funding available to primary schools here is increased, Carr warns.

This is despite the best efforts of teachers such as those at Marley Grange National School and others in schools throughout the State.

As a first step, the Government should reintroduce the grant for PE equipment which was abolished by the previous minister for education and science, Noel Dempsey, Carr says. This should in turn be accompanied by a significant rise in the capital inverstment in sports infrastructure here.

"The net result of under-funding of schools is that exposure to different sports and even participation in sports is dictated by the size of wallets and purses of parents," he explains.

"Every school should have indoor physical-education facilities so that schools are not dependent on the weather to run their programmes . . . Failure to resource physical education among the young is storing up a problem for the future."

Irish children are following global trends. They are getting fatter and taking less exercise. But are we doing enough? Teachers are getting to grips with the new physical education curriculum, but do we have the facilities for them to implement it? And should the health of our nation be the sole responsibility of schools?