The numb feet are worth it to highlight those who don't have a choice
John McBride once said he decided to run the Great North Run barefoot because he wanted to show solidarity with people who didn't have a choice about whether to wear shoes or not.
In 2008, with 12 of the half marathons already under his belt, this council worker from Consett in County Durham took his trainers off for the last mile.
He did it again in 2009.
Now, ahead of his third shoeless run, he's off to Kenya to do two things.
First, he hopes to meet a woman who spent many of her formative years running barefoot out of necessity.
Second, he'll be seeing where some of money he helps raise is being spent.
John, who runs for the Catholic aid agency CAFOD, is going to Nairobi to visit three of their projects in the area.
One, in Kajiado, is trying to put the Masai people on the road to self sufficiency.
CAFOD has built a 500,000 litre dam and provided livestock
Another, in Thika, works with people who are HIV+, helping them make a living and making sure they're fed so their drugs have a chance to work.
Barefoot in the hills
Then John is going to do some running.
Barefoot, in the Ngong hills, not far from Nairobi.
Who better to offer training advice than a group of reformed Masai warriors? Where better than somewhere hilly, steep and scenic?
It'll come in useful on that last stretch, Redwell Lane, going down to the sea at South Shields, as the ground drops away from the runner's foot.
He also has plans to meet Tegla Loroupe, who won the Great North Run in 1993 and is a world marathon and half-marathon champion many times over.
She's one of those people John was talking about, who had no choice about footwear: "She started out as a barefoot runner, she used to run to school every day, which was, I think, about six or seven miles each way.
Tegla Loroupe won the Great North Run in 1993
"Always barefoot because they just had no shoes."
Loroupe now has her own foundation and campaigns for peace via sport, similar to CAFOD's work in the slums of Korogocho.
John says the aid agency's St John's Sports Society is based in one of the worst slums in Nairobi and he's impressed with their success.
He's heard about one man in particular: "You knew he was possibly going towards gang fighting and all this kind of thing and he went there and he took up karate and he's now in the national team.
"He's come from a very deprived background indeed and he's making something really good out of himself with the help from the club."
The last mile
Some of those living here have the chance to change their lives
John didn't train for his first shoeless run; he was worried he might injure himself and not be able to do it at all.
And now he still thinks, despite any tips he might get in Kenya, he'll keep his shoes on until the last mile: "The problem is at about 11 miles there's a drink station and, of course, all the bottle tops go on the ground which makes it really tricky to run through.
"I think until you get past the last one of those it would be really difficult to run barefoot."
The visit has benefits on both sides. John sees and learns and, in return, he can tell people how their money is being spent: "I'll be able to go out and say, actually, when you give a pound to CAFOD, this is where the pound goes."
These days, with so many people running the Great North Run, available sponsors are chased by more and more forms and office emails.
John says it can be difficult to get people to donate for it: "Because there's 50,000 sponsor forms floating round the North East, we're all sort of fishing in the same pool, dreadful phrase.
All sort of sports are on offer including football and athletics
"People you know even in your own office, you have three or four people who are doing the Great North Run and they are all trying to get sponsorship for their particular good cause.
"The advantage of CAFOD is that it's got the church behind it so I've put sponsor sheets at the back of the church and hopefully people will say, well it's kind of our charity, and so you can get quite a bit of sponsorship that way."