So important in fact that in 2011 O'Reilly registered Trinity Comprehensive -- the first school from the Republic to do so - with EDEXCEL, a British Examinations Authority. Having been approved by the authority, Trinity now offers its fifth and sixth year students the opportunity to take the British GCSE exam in physical education.
O'Reilly had decided to take a look at what Britain had in place after being left frustrated by the fact that physical education is still not an examinable subject here at second level.
"I thought it was really, really good. There's a short course and a long course and I thought the short course was doable in a year. With the short course you pick two sports and you assess those, you then analyse a sports game plus you do an exam paper," says O'Reilly.
At the end of its inaugural year in 2011/2012, eight students had passed the course with flying colours.
"I think it's fantastic. I think you have a ready-made brilliant course there. With a small bit of initial administration you can get a whole bunch of youngsters excited about the theory content of what is a very important subject," he said.
Both the students, O'Reilly and fellow PE teacher Gerry McDonnell volunteer to do the course in their free time, approximately two hours a week, with Ballymun Regeneration Limited helping to fund the programme.
"The students are obviously interested in sport while their self-esteem and their mental and physical wellbeing grows by their decision to do an extra subject," says O'Reilly.
Fifth year student Keith Mills, who is on a rugby scholarship, sees the course as "a great opportunity" to learn the theory aspect alongside the practical and physical fitness side of PE.
Having kick-started the course other schools are now following in the footsteps of the northside school.
"At Trinity Comprehensive we're delighted to have started the GCSE physical education course and we're also delighted other schools like Sutton Park, Ashbourne Community College, St Mary's, Dundalk and Loreto College, Mullingar have picked up on it," concludes O'Reilly.
Trinity Comprehensive School, Ballymun is holding a workshop on 'Delivering a GCSE Physical Education Course in Ireland' on January 12.
Contact: Paddy O'Reilly, 086 174 3836, email: firstname.lastname@example.org