Originally Posted by guadzilla

I had a medical truck-up last year, where the doctor prescribed me a far-too-heavy dose of prednisolone for far too long (for an eye inflammation related to an old MMA injury). I was on this course for about 3 weeks or so before it was changed, but it completely destroyed my fitness. I was waking up at night with cramps in all sorts of places, my running stride went for a toss and from being able to enjoyably run for 90-120 min, i couldnt run for 3-4 min without stopping. Took me an additional 4-5 weeks before i felt well enough to resume training normally - and i had to rebuild my entire running fitness from near-zero. Weirdly, my cycling, while affected, didnt deteriorate as badly.