The Scot suffered a torn calf at the Anniversary Games 10 weeks ago, which wrecked her preparation for Doha.
She runs in the 1,500m heats tomorrow bidding for her first global outdoor medal. And the 26-year-old, the reigning European champion who won the 1,500m in London in August despite suffering the injury midway through the race, has eased any fitness fears.
She said: “I’m happy with how things have gone. The calf is 100 per cent so I’m not worried about that at all.
“I can go into the competition being confident in that and my body, but it’s not been the most ideal preparation over these past couple of months.
“To win a medal now, especially gold, would be to be an even bigger achievement than what it was a few months ago. That’s definitely still on the table.
“Going into this year I said I wanted to win a medal in Doha. That’s always been my target and I think I am still capable of doing that.”
Muir has been training in South Africa ahead of the Championships and, when she was unable to run, was swimming to maintain her fitness.
“I did a lot of cross training in the pool,” she added. “It is difficult with the calf because you cannot do that much weight-bearing stuff, so I was in the pool twice a day every day trying to do as much as I can.
“I was at altitude and I kind of forgot swimming at altitude is really, really hard.”
Muir must also negotiate Thursday’s semi-final ahead of Saturday’s final and admitted she is going into the unknown after a disrupted build-up.
“I guess this is the first time I have not raced that period going into a competition, but I’m lucky that it’s not a one-off race like the 10,000m,” she said at Great Britain’s team hotel in Doha.
“I have got the heats, I have got the semi, just to get back to the routine.
“I’m fortunate too that with the training we do the first race of the season for me is usually a big one.
“Our training is so intense so I am used to that intensity. I know I can usually put a good race out there straightaway. I’m not worried.
“When it happened I knew something wasn’t quite right. I have quite a high pain threshold and thought, ‘Well, we’ll see how things go’.
“As I crossed the line I couldn’t walk properly. We knew what it was straight away and we were on it straight away. We got ice on it and MRI the next day.
“We knew what we were doing. Bad things happen but it is how you react that matters.”