A "bored" former athlete will be spending his birthday running a marathon in his garden - despite it measuring just 6m (19ft).
James Campbell, 31, has calculated he will have to traverse it 7,000 times to log the required 26.2 miles.
He expects the endurance feat, which he has dubbed "literally the most stupid thing I could think of to do", to take about seven hours.
Mr Campbell, from Cheltenham, hopes to raise £10,000 for the NHS.
Spending the last few weeks at home had driven him "a little bit crazy", he said.
"I'm guessing I won't be able to build any speed up and I've got to contend with a patio, stones and grass," he said.
"I am going to measure out a couple of lines of 6m as the actual length of the garden is just over 7m".
"I will plod up and down for as long as it takes," said Mr Campbell.
Mr Campbell is a former world-class javelinist and was a youth footballer with Cheltenham Town as a teenager.
After injury ended his athletic career, he returned to football and now plays for Hellenic Premier League team Brimscombe and Thrupp.