Checking out the stair climbers are Ashburton volunteer firefighters Warren Maslin (left) and Nathan Speedy, with EA Networks Centre gym staff member Amy Ferguson (left) and gym and fitness manager Jenny Soal.
Gym staff are taking on Ashburton firefighters for the fitness title and the gloves are off.
All gym users and supporters are invited to get along on Saturday from 10am to show their support.
There will also be a special Les Mills Mashup activity programme running in the stadium between 10am and noon, with participants asked to give a donation to the bushfire appeal.
The programme includes 20-minute sessions each of toning, cardio, Bodyattack, CX Worx, Bodycombat and Bodybalance.
The two stair-climbers from the gym will be moved into the stadium for the special Gym versus Firefighters challenge.
