David Weir said he is feeling "confident" as he prepares to defend his London Marathon title while competing in the race for the 20th time.
The 39-year-old, who has won eight elite men's wheelchair titles in his home city, said he feels "in good shape" despite a "frustrating" few months.
His preparation has been hampered by a car crash in December, illness and an infection in his foot which forced him to drop out of the Boston Marathon earlier this month, partly because he did not want to risk missing the London race, and he also missed the Tokyo Marathon in March.
"I have had a bit of a stop-start winter. It's been frustrating but I'm in good shape," he told the Press Association.
"The last few weeks the training's been great."
Weir said being forced to rest while his foot was infected may have been "a blessing in disguise" after a block of hard training when he was doing 140 miles per week.
He added: "I feel confident. You don't want to be too confident because you know the guys who raced in Boston pushed really well and they did well in Tokyo as well.
"I'm happy to be here, and I'm competing with the best in the world. I'm more relaxed than I have been."
The London Marathon is special for Weir who is from Wallington, in the London borough of Sutton.
As a youngster he was keen to do a sport like his three older brothers who boxed. Weir started wheelchair racing with the help of a grant from his local council towards a racing chair.
"I remember seeing the marathon on TV. It was the only time you saw people in wheelchairs doing anything," he said.
"It's the first time I ever saw disabled people on TV."
He credits the race with inspiring him to take up wheelchair racing.
"It's the best race for wheelchair racers in the world," he said. "I never get tired of the London Marathon. You never get bored of winning.
"They have improved it, coming up with ideas, putting the prize money up, making sure the best people are there.
"They look after us, we are treated like professional athletes. They are just doing everything right."
The Flying 400 sprint competition has been introduced to this year's race.
Wheelchair racers will complete a 400-metre time trial just after 20 kilometres (12.5 miles), with the fastest man and woman each receiving 10,000 US dollars.
Weir said the time trial section, which has also been introduced in other marathons, is "fun" and a good idea for racers and the crowd but will not affect his race plan.
"I forget it's coming," he said. "I'm more focused on the finish. In New York I completely forgot.
"I'm more interested in the end but if I see they are sprinting I will make an effort.
"It's innovation. It's good for the other racers."