Runner Stephen Edwards, originally from Llanberis, thrives on competing in challenging running competitions and is the organiser of the annual Snowdon Race.
But during this weekend's Lloyds TSB Cardiff Half Marathon, Stephen won't be among the 15,000 runners. Instead, he has temporarily hung up his running boots and replaced them with a microphone to become an S4C commentator.
The Cardiff Half Marathon has fast become the biggest and most popular race in Wales, and to mark the occasion of the event, S4C's cameras will be there to broadcast extensive highlights.
Sarra Elgan presents the highlights programme with Dot Davies among the runners throughout the race. Stephen, who now lives in Llanfairpwll and divides his time as a graphic designer and broadcaster, joins John Hardy in the commentary box.
Stephen says, "For the duration of the race, I'll be analysing and commenting with John Hardy. To be honest, it's quite nice to be the other side of the microphone but I will be a bit jealous of the runners when they're making their final preparations. I'm going to run the course before the race to get a feel of the challenge that lies ahead for the runners."
Elite racers and fun runners will all face the flat and fast course and the great atmosphere of the event that is becoming known as the Great Welsh Run.
Stephen knows the Cardiff Half Marathon quite well having experienced it on three occasions. Last year saw him complete the race in 1 hour and 42 minutes - a personal best - but why does he think the race is becoming increasingly popular?
"The Cardiff Half Marathon is the only time of the year when you have the freedom to run around our capital city, passing the landmarks and notable scenes along the way. It's a great feeling when you're running down to Cardiff Bay - passing the Millennium Centre and the National Assembly for Wales - and back up through the city centre whilst passing the Millennium Stadium."
After his stint in the commentary box, Stephen will don his running shoes as he takes on his first ever marathon - the brutal Snowdonia Marathon. Viewers can follow his progress on S4C's Marathon Eryri at the end of the month.
© 2012 S4C
O Gymru / Made in Wales