The Scot claimed her first outdoor world medal after sealing third in the 1500m at Hayward Field on Monday night.
She clocked a season’s best of three minutes 55.28 seconds to finish behind Kenya’s Olympic champion Faith Kipyegon and Ethiopia’s Gudaf Tsegay.
Yet Muir was on crutches in February after a stress reaction to her femur in her right leg and admitted it was touch and go she would even make it to Eugene.
“It was the most significant injury I’ve ever had in my running career. For two months I couldn’t run,” she said, after adding to her Olympic silver medal from last year. “That was very, very frustrating, especially as I was going so well in January.
“With the champs being almost a month earlier than normal as well it meant I had about three months less time to prepare than normal. So not ideal. I just knew I had to have a lot of confidence in myself and my team that we would be able to get back that. We did it and we got that medal.
“I was diagnosed with a stress reaction of the femur start of February, that was two weeks on crutches. Then another six weeks of just in the pool, in the gym, alt-Gs, anti gravity treadmills, tiny runs on grass, slightly longer runs. We gradually got there.
“We were lucky we caught it early. We knew something wasn’t right. We got some advanced imaging. We found out what it was quite quickly. Had it been a fracture it would have been me out for a long, long time.
“It was lucky it was a stress response. Even so it was in an area of the bone where you do have to offload it a lot.”
In Oregon, Muir was involved in a breakaway with Kipyegon, Tsegay and Hirut Meshesha almost immediately as the race went out hard.
Meshesha was then dropped with over two laps to go as the medal-winning trio fought it out for their podium spots with Kipyegon taking the title.
“I’ve been fourth, fifth twice and sixth at the World Championships, I was so scared being third and someone was going to pass me,” said Muir.
“That’s what happened in London 2017, I was second and came fourth. I was like ‘this isn’t happening again’. I was going to give absolutely everything until I got to that line.
“Everything hurt. That last 100m my legs were just on fire. I felt like I couldn’t lift them, I was running in treacle. Everything was burning.
“But I knew if I got to the finish line it was going to stop. I was very, very tired when I did get to the line but that’s what you want to be, knowing you’ve given absolutely everything. If I’d got to the finish line, not given absolutely everything and lost I’d have been absolutely devastated.”
Muir, 29, now turns her attention to the Commonwealth Games in Birmingham as she aims to complete her medal collection.
She said: “One more, I’ve got the Commonwealths to get. I started in my running career wanted to run all six champs, I’ve done that, then make the final of all six, I’ve done that.
“Now I want to win a medal at all six. It’s five down one to go.”