what does 100+ pounds actually feel like?

I found out today just how heavy I am, not necessarily in the overweight sense but in the my-muscles-are-atrophied-oh-god-I-am-so-out-of-shape way. My arm felt heavy as I tried to curve it over my head. my feet felt heavy as I tried to pivot and hop. Dance class was a truly humbling experience where I felt like instead of a network of well-oiled muscles, I was a bag of sand that just sags and shifts in different directions. Okay, okay, I'll stop, because I held my own just fine and the self-pity's over the top. but...damn.