Typically my coworkers and some friends laugh when they hear about me working out. They laughed more when I started commuting to work. But bring up the idea of doing a century, and even my best friends say things like "Brad, I really don't think you should try doing that. You're not an athletic person. Don't kill yourself." I'm not a big guy. I'm 5'11" and weighed around 214lbs back in October '05 and got down to around 200 in early January of this year before injuring my knee. After staying off it for quite some time (with mixed results) and heading back to 204lbs, I started working out again in May and then biking in June. I'm not down to around 190-191lbs. My speed is not quick. Maybe 15mph on flat ground without any wind resistance. Usually somewhere between 8 and 13mph would be my best guess (no computer on the bike).