What do you hate most about your work out? Hauling yourself off the sofa? The pain? Venturing outside in Lycra?

The worst part for me is hitting that wall of boredom. While training for a 10k last year I spent hours preparing iPod playlists to keep me entertained, but still found running, especially on a treadmill, tedious. How you marathon runners do it I don't know. So this year I decided to switch things up.

Which is how I found myself entering Tough Mudder - a 12 mile obstacle course which will see me crawl through muddy water under army-style nets, run through electric wires, plunge myself into ice-cold water and drag myself over Everest - a 15 foot curved wall, amongst other things.

The name says it all; it’s going to be terribly tough and mega muddy. And wet. And cold. And painful. But I definitely won’t be bored. And pain is temporary, right?

Up until Christmas my training consisted of a few long runs a week. I started a few light weights at the gym but that would not be enough to pull myself over the Berlin Wall obstacle. So when I was invited to a new outdoor fitness class at Hillingdon Athletic Track where members are training for the event, I went along. And dragged my fellow reporter and friend, Zoe, with me. I don’t think we’re friends anymore.

The class consists of rounds of exercises, with a new one added each time. Instructors Murray Williamson and Dean Leow - personal trainers at Hillingdon Sports and Leisure Centre in Gatting Way - call it The Gauntlet. Ominous.

The Gauntlet started with 10 squats then we added an agility ladder, bicep curls with a resistance band, squat jumps, sit ups, hill sprints, squats while holding tyres, flipping tractor-size tyres, bunny hops over bars (they sound cute - they’re not) and bar rows, running back to the start after each set.

After eight rounds I thought (prayed) the class was over, but we were only half way though. Next up was 20 metres of walking lunges, then 50, then 100, running backwards to the start line after each set.

As my legs turned to jelly, Murray announced it was time for more squats. If an exercise can be en vogue, 2014 is the year of the squat. The move works your quads and glutes... Beyoncé and her buns of steel have a lot to answer for.

With the help of Moby’s Bring Sally Up, we squatted up, down and held them as the lyrics demanded.

Then it was ab time. At least we got to lie on the floor for this bit.

After 12 reps of five different exercises it was the grand finale - The Plank. Sixty seconds of holding yourself up on your forearms and toes keeping your body as low and straight as possible.

Finally, we were done. Was that really just an hour?

Exhausted as I was, my endorphins were flowing and I finished sore but smiling, and the other girls agreed.

“The first time I ever did the class, the next day, the only thing that didn’t hurt was my eyebrows,” said Stacey Reid, who is also running Tough Mudder on April 26 with seven of her friends who have also been attending the class.

“The variety of exercises and high intensity training keeps you on your toes.

“But no two weeks are ever the same and it’s personally challenging as well as fun - if this is your idea of fun.

“You can really see a change in your fitness levels and your body shape and everyone is so encouraging.

“The whole team very much look forward to it every week.”

Hill sprints at Women's Outdoor Fitness, Hillingdon Athletics Track. Zoe Drewett and Hannah Raven get shouted up the hill.

As if the physical challenge is not enough, Stacey and her team of ‘Buff Mudders’ have also set themselves a fundraising goal for Brain Tumour Action UK.

“One of the team member’s mum has unfortunately been diagnosed with a brain tumour and we all wanted to pick a charity where our money will really make a difference with support, counselling, education and research,” she explained.

If they raise their £3,000 target, they will keep the charity going for another year.

“Us girls have a very ‘work hard, play hard’ lifestyle, but to get our bums into shape we had to give ourselves a reason.

“Tough Mudder, which is for a great cause, seemed the best one to actually get us on the treadmill.”

They each paid an entrance fee of around £90, which goes to Help the Heroes.

Sit up time at Women's Outdoor Fitness, Hillingdon Athletics Track

Along the gruelling route, there is one thing that will keep the Buff Mudders going.

“I can safely say we’re most looking forward to the Strongbow at the finish line,” said Stacey.

“No, seriously, we’re actually really looking forward to laughing at each other going through the electric shock obstacles.

“We all cannot wait to help each other through and really pull together as a team.

“We are such a close group of friends and Tough Mudder is all about the team work. And of course we’re also looking forward to the strong men lifting us through the majority of the course!”

Stacey says they are most worried about an obstacle called Arctic Enema - and now I am too.

“The name speaks for itself. It’s a huge dump truck full of ice and water, set at about a degree above freezing all day, and you have to jump in, get your head under, and get at the other end as quickly as possible before muscle paralysis starts kicking in,” she said.

“Oh my goodness. Talking about this has made it seem all the more real. I’m now really nervous.”

GULP.

Even if you are not training for an event, I would recommend the class to anyone who is looking for a challenging full-body workout and is sick of staring at the gym walls.

“Do it. It’s 100 per cent worth every ache of the muscles that you’d forgotten were there or didn’t even know you had,” said Stacey.

“If you want to feel like you’ve worked hard, this is definitely for you. You will sweat, you will hurt, it will rain and it will be cold. But you will definitely go back for more.”

As I sit typing at my desk my muscles are gradually seizing up. I’m not looking forward to tomorrow when the real pain kicks in, but it’s definitely worth it. Thank goodness we have lifts at Gazette House.

The classes run every Wednesday at Hillingdon Athletics Track, come rain or shine, and cost just £6. The men’s class is from 6-7pm and women’s 7-8pm. It is open to everyone - just turn up.

The Buff Mudders are hosting a fundraising event on March 29 at Uxbridge Golf Club to raise more money. Tickets are £10 and there will be live entertainment from StaceySings, DJs, a raffle with designer clothing, beauty treatments and an event DJ package worth £1,370. For more information contact Stacey at reidst30@gmail.com.