It is billed as the ‘safest most dangerous event in the world’.
It consists of an eight-mile run in freezing cold conditions, including a gruelling mud run.
if that is not enough, it will be followed by the Killing Fields assault course - which includes barbed wire and threatens ‘cuts, scrapes, burns, dehydration, hypothermia, acrophobia, claustrophobia, electric shocks, sprains, twists, joint dislocation and broken bones’.
Sunday’s Tough Guy challenge doesn’t sound like a barrel of laughs at the best of times... especially not in January.
Some people spend all year training for the eventr, but for Boston’s Nick Maddison, it is just number 19 of an action-packed year.
Maddison, of Albert Street, is taking on 28 challenges in 14 months to raise cash for the Alzheimer’s Society, in honour of his grandad Norman Sculthorpe.
And the Tough Guy event is his introduction back into action after a break from competing over the festive period.
An injury also curtailed Maddison’s training over Christmas, while the bad weather put paid to his hopes of competing in the Gloucester Marathon this weekend.
He is currently looking for another event to replace the marathon, so he can fulfil is 28-event schedule.
Marathons (he has done three already), ultra marathons and more await him before his April deadline... if he makes it through the Tough Guy challenge, that is.