Great Britain's Greg Rutherford will compete for the last time before his retirement at Saturday's Great North City Games in Newcastle.
"Of course, there is some sadness in that. But I'm ready to retire," the 2012 Olympic champion told the BBC.
"How I react to that, I'm not too sure yet - we'll see."
Rutherford took the long jump title on 'Super Saturday' at London 2012 - when he, Jessica Ennis-Hill and Mo Farah all won golds in the space of 46 minutes.
It was the first time three gold medals had been won by British athletes in one Olympic athletics session.
Rutherford competed at the London Anniversary Games in July, where he bowed out with 7.55m after two no-jumps.
"I've had a lot of time to get my head around this. London was very, very emotional for me," the 31-year-old said.
"My body is most certainly ready for me to retire and move on to new things. Getting out of bed in the mornings nowadays is quite difficult. I need to let it recover properly and move on to something new.
"I'm old enough now, I've done this long enough - it's time to let the youngsters takeover and push it on to a new level."
Rutherford is one of only five British athletes - the others being Linford Christie, Sally Gunnell, Jonathan Edwards and Daley Thompson - who have won Olympic, world, Commonwealth and European gold medals.
Rutherford suggested in June that he would switch to track cycling after his retirement from athletics, and says that is "absolutely still in the pipeline".
"I think I'm going to give it a go. I'm just about young enough to do it. I'm powerful enough, definitely," he added.
Great North City Games
Saturday, 8 September
Double Paralympic gold medallist Jonnie Peacock marks the end of his year-long break by returning to competitive action in the T44 100m.
Reece Prescod and Harry Aikines-Aryeetey will lead British hopes in the men's 150m and Jodie Williams and Daryll Neita go in the women's version.
European champion Laura Muir will compete in the 1500m events, which take place in Stockton from 09:30 before live BBC TV coverage.
Britain's four-time Olympic champion Mo Farah will race in Sunday's Great North Run - a 13.1-mile course from Newcastle's city centre to the coast in South Shields. A win for Farah would make it his fifth consecutive victory in the men's race.