Those taking part in tomorrow's London Marathon are actually getting a bit more than they bargained for, at least when it comes to the distance involved.
According to data from TomTom Sports, marathon participants actually tend to run much more than the official 26.2 miles they sign up for.
The formal distance is measured by an official with a measuring wheel over the perfect, shortest possible line.
But, with so many people giving the marathon a go - over 50,000 taking part - runners will need to weave in and out of a lot of foot traffic.
For last year's London Marathon, those taking part in the gruelling race ran, on average, 0.45 miles more than the official distance.
And in other marathons across the globe, TomTom recorded a similar story.
The distance covered by runners in marathons across the world:
|Marathon||Mean finisher distance|
|New York||26.69 miles|
Elsewhere, there's set to be good news for runners on the weather front.
"Runners can look forward to “a mild, but not hot, day with a light breeze," said the Met Office. It will be a dry day and the temperature is expected to be warmest at 4pm reaching highs of 15 degrees.
When and where is the London Marathon?
The 37th annual race is tomorrow Sunday 23 April. The course begins in Blackheath before heading down to Greenwich and then towards the City.
The wheelchair race starts at 9am, followed by the Paralympic runners taking part in the IPC Athletics Marathon World Cup. Then the elite women's group sets off at 9.20am, followed by the elite men's group and thousands of fun runners at 10am.
Traditional coverage will be on BBC One, with highlights on BBC Two.
(Click or tap to view full-sized version of the entire course.)
What travel disruptions will there be?
A detailed list of all expected road closures can be found here.