She went from running up to five miles, to only being able to walk the length of around three city blocks.
Her body lost mobility and she began the long, slow process of exercise and physiotherapy to try and regain her body function.
It was at this point she spotted actress Selma Blair announcing on Instagram she had the nervous system-damaging disease multiple sclerosis.
The 47-year-old star of films including Cruel Intentions, Hellboy and The Sweetest Thing, posted images of herself using a mobility bike. The two began private messaging and Blair bought Main one of the bikes. Main says it has changed her life.