There's cold water to drudge through, fences to scale, cargo nets to clamber over, tubes to squirm along and lots and lots of mud.
And if that doesn’t sound gruesome enough, you’ll be taking all this on in the dark.
Reaper Events is one of the latest organisations to join a growing army of obstacle races springing up across the UK.
Based in south Warwickshire, the biannual runs are held in Meriden, where plucky contenders don head torches before pelting off into pitch black woods to contend with a mud-smothered assault course.
The idea was dreamed up by a dentist who spends his spare time planning his next challenge.
“I had done mud runs in the past,” says Chris Nicoll, of Stratford’s Evesham Place Dental Practice, “and Colin, a good friend of mine, came to me and said ‘I need to get fit and I need a training goal’.
“He wanted to sign up for Tough Guy but was put off by how much it cost, so I said to him ‘Let’s do our own’.
“We started thinking about it and asked ourselves ‘What’s our unique selling point?’ That’s when we decided to do it in the dark.
“We are the only people in this country, as far as we know, to do an unlit obstacle race, fully in the dark.”
Chris, 46, and his friend Colin Spafford, 47, set up Reaper Events, charging each competitor £44 to undercut most of their rivals, and joining a swell of obstacle racing and mud running organisations that are catering to surging demand.
The biggest of the pack, Tough Mudder, was started four years ago by a pair of young Brits in New York and has since swept across the US and UK.
More than a million people have now taken part in a Tough Mudder events which can include icy water, fire runs, barbed wire and – believe it or not – live electric cables.
Their prize for surviving all this? An orange headband.
Other options for athletic sadists include Tough Guy, Mud Runner, Spartan Challenge and Wolf Run.
Even Cancer Research’s popular pink Race for Life 5k run has now launched a women-only splinter event with obstacles, Pretty Muddy.
Mud running has become a multi-million pound industry with its own niche websites and magazines, and the fact that competitors have to sign a waiver beforehand, accepting the risks of the race, doesn’t put them off.
Chris, a seasoned skydiver and thrill-seeker, says: “We do everything we can to make sure it’s safe, with stringent health and safety assessments of each obstacle.
“We have public liability insurance, employers liability insurance and accident insurance.
“We also have paramedics on site. We don’t want anybody to get hurt but if anybody does we want to make sure they’re looked after.
“I honestly think if there was no risk whatsoever people wouldn’t do it.
“But we make it seem more risky than it is.
“Before every event we walk every inch of the course as it goes through the woods and any twigs or branches that could poke somebody in the eye we take away.
“People wouldn’t realise that when they’re running through the woods with a headtorch on, but we reduce the risks as far as possible and anything we can’t get rid of we manage.
“At the end of the day, though, people could trip over a tree root or anything.
“We get quite a lot of grazes with people crawling around and climbing over things. The paramedics will do four to six minor treatments at most events.
“And we had one person that needed assistance off site after jumping off an obstacle and landing badly on their ankle.”
The six-mile (10km) races are held at Meriden’s Heart of England Conference Centre, with daytime races as well as the unlit night course.
For the daylight event competitors set off in groups of 50 but at night the headtorch-wearing teams are reduced down to between 10 and 15 runners, leaving in timed slots to preserve the darkness.
Each course challenges runners with 25 to 30 obstacles, which could take longer than two hours to clear for a team that isn’t used to running or isn’t feeling competitive.
But why are so many people choosing to ditch standard running in favour of facing hurdles and obstructions?
“People do it because it’s a great training goal,” says Chris, “that’s why we got into it in the first place.
“Every time you put on your running shoes or go to the gym you’re doing it with a purpose.
“Most people do the course with friends as an excuse to get out together and have a laugh. Our biggest team to date was 60 people.
“And, believe it or not, people like wading through mud!
“Sure, you can just go for a run in the park or through the woods, but you won’t have the extra challenge of these obstacles, the support of your mates and the camaraderie that so many people have taking on something like this in a group.”
He adds: “I think running-based sports are going through a cycle. The people who traditionally did road running are bored now and taking up cross country.
“The next thing to come along is triathlons, but that takes a lot of training and people tend to do that with the very focused target of beating a time.
“Our sort of event is more accessible. Most people, with a bit of training, can do six miles.
“We’ve had people who’ve walked the whole way and done it in over two hours, while the quickest team did it in 45 minutes.”
Chris has found new challenges himself in designing and building the obstacle course and putting it to the test before the runners arrive.
He says: “When you get to the end and you’re caked in mud, with bruises and scratches, your adrenaline is really going.
“It’s fun scrambling over obstacles. It’s fun getting covered in mud and helping your mates out.
“When I tell people I do this they look at me strangely and say ‘You must be crazy’.
“But that gives me quite a buzz.
“I think it’s great being able to say ‘I don’t just jog along the road I run through mud and take on obstacles’.
“It’s certainly very different to my nine-to-five job. It’s a complete release.”
* The next Reaper run will take place on October 18. See www.reaperevents.co.uk