Yesterday I rode my FG for the first time in almost 3 years...
 

...and today, hoo boy are my quads ever sore.

I guess I'm a bit surprised that there's that much of a difference in how the muscles are worked, compared to a coastable bike. I did the same route last week on a multi-geared bike and wasn't sore at all the next day.

Yup! I've been saying for years fix gears are 25-33% harder than freewheels. (Meaning the freewheel mechanism. present in both "freewheels" and cassettes.) I rode mine yesterday and am feeling it today. (And I went for a walk yesterday evening because I knew if I didn't today wasn't going to be fun.)

My latest saying. "You ride gears to make your body fast. You ride fix gears to make your body hard."

I had converted my FG to SS years ago. I just built up a FG. Yikes, maybe there was a reason I went to SS!

Anyway, I will keep it FG for a while and see if I end up liking it.

I liken it to running. There, also, your legs are always moving in proportion to your speed. No option to coast when you're running down a hill, as much as you may really want to!

Well, it took about 4 days for the pain to completely go away. I've ridden my fixed gear a few times after that, and no pain at all afterwards. Just some cobwebs that needed clearing, apparently.