This weekend at Tough Mudder London South I am attempting something that does not officially exist.
A Tough Mudder Trifecta weekend.
Well, sort of.
The official Tough Mudder Trifecta is earned by completing all three of the main Tough Mudder formats during the season: a 5K, a 15K and an Infinity.
Infinity is the endurance version. You start with the 15K course and then keep going, choosing additional 15K or 5K laps as the clock continues to tick. To be classed as an official Infinity finisher, you need to complete at least 20km.
So, at its most basic level, the distances involved in a Tough Mudder Trifecta are:
Infinity: minimum 20km
Tough Mudder 15K: 15km
Tough Mudder 5K: 5km
Total: 40km.
And that number suddenly looks rather familiar.
Because at London South this weekend I am booked to run the 15K and 5K on Saturday.
Then, because apparently finishing them and going home would be far too sensible, I am coming back on Sunday and doing exactly the same thing again.
That gives me approximately 40km of Tough Mudder in one weekend.
It isn’t an official Trifecta. I am not pretending it is. There is no Infinity entry, no eight-hour clock and certainly no Trifecta medal waiting for me at the end.
But in terms of the minimum distance?
It is basically a Trifecta.
Hence:
The Non-Official Tough Mudder Trifecta Weekend – Take 1.
Actually, I’ve Already Done Part of This
There is another reason I like looking at the weekend this way.
At Tough Mudder South West I completed the 15K followed by the 5K.
Twenty kilometres.
That happens to be the minimum distance required to finish an Infinity.
Again, absolutely not claiming that I completed an Infinity at South West. Infinity is a very different event, with timing, repeated laps, different rules and eight hours in which to keep going.
But I now know that I can cover that minimum distance over Tough Mudder terrain.
London South takes things another step forward.
Can I do 20km on Saturday, recover, get up the following morning and do another 20km?
I am fairly confident the answer is yes.
But that isn’t really the interesting question.
The interesting bit is how I cope with it.
What do my legs feel like on Saturday evening?
How quickly do I recover?
What do they feel like when I start again on Sunday?
How much slower am I?
What hurts?
What doesn’t?
What do I eat?
What works?
What turns out to be a really stupid idea?
These are becoming much more important questions than simply whether I can cross another finish line.
Because Eight Hours Is Coming
The real target sits a little further down the road.
Tough Mudder London West in May 2027.
That is where I intend to take on my first proper Tough Mudder Infinity, followed by the 15K and 5K on Sunday.
Infinity.
15K.
5K.
One weekend.
A genuine Tough Mudder Trifecta, assuming the current format continues into 2027, but with my own added requirement of doing the whole lot at the same event.
And London West is only part of the journey.
Seven weeks later comes World’s Toughest Mudder.
Twenty-four hours.
Which makes these slightly ridiculous 40km weekends rather useful training.
So How Far Could I Actually Go in Eight Hours?
This is one of the things I really want to learn from London South.
The minimum Infinity target is 20km.
I know I can cover 20km at a Tough Mudder because I’ve already done it.
But completing 20km and completing as much distance as possible within an eight-hour event are two rather different things.
For 2026, Tough Mudder’s first additional Infinity distance award comes at 30km.
Then there are awards at 35km, 40km and 45km.
Reach 50km and things get considerably shinier, with a 50km Hex and belt buckle.
My current plan for London West is deliberately conservative.
First job: become an Infinity finisher.
Get beyond 20km.
Get the medal.
Learn how Infinity actually works.
Then at later Infinity events during 2027 I can start chasing the bigger distances.
Thirty kilometres.
Eventually fifty.
But there is an obvious question.
Could I already manage 30km?
Maybe.
With another eight months of training between London South and London West?
Potentially, yes.
And that is where this weekend becomes particularly useful.
If the technology behaves itself and I can get decent timing and distance information from both runs, I should start getting an idea of what my current pace actually looks like across 20km of Tough Mudder.
It won’t translate perfectly to Infinity. Normal event waves, obstacle queues, breaks between the 15K and 5K and all the other differences mean this isn’t an eight-hour simulation.
But it gives me a baseline.
If I know how long 20km takes me now, how I feel afterwards and how much I deteriorate when I go again the following day, I can start answering a much more interesting question:
If somebody gave me eight hours, how far could I keep going?
And Then We Do It Again
Because London South isn’t the end of this experiment.
Tough Mudder Manchester is coming in October.
And I have somehow booked exactly the same arrangement.
15K and 5K on Saturday.
15K and 5K on Sunday.
Another approximately 40km weekend.
The Non-Official Tough Mudder Trifecta Weekend – Take 2.
That gives me two opportunities before the end of 2026 to test the distance, recovery, fuelling, kit and increasingly questionable decision-making involved in putting repeated Tough Mudder runs together.
Then the winter training starts.
And when I arrive at Culden Faw for London West in May, the numbers on the tickets finally change.
Saturday won’t say 15K and 5K.
It will say:
INFINITY.
And on Sunday?
15K.
5K.
That one counts.
Probably.
First, however, I need to survive Take 1.
London South awaits.
40km. Two days. Four Tough Mudder runs.
Time to find out what happens when Tough Smudge stops treating each finish line as the end and starts treating it as preparation for the next start line.
Endure. Overcome. Make It Count.