Not a gym person, but did do some mountain bike trails today. I'm not sure it was wise, though, since the trails were wet and covered with leaves, I spun trying to get up the hills, and tore up the trails a bit. And the big ole spiders were busy making webs across the trail, and while removing a spider from my face, my front wheel hit a root and I had to bail out. Luckily all I got was a scrape on the shin.