Originally Posted by
LWB_guy
Some of the same muscles are used. But different muscles are used too. I too stopped riding an upright bike. The muscles in my upper legs became bulky by riding my 'bent over three thousand miles so far this year. Now when I stand upright, I feel like stretching my legs while keeping them perfectly straight. At the same time, I stretch my arm muscles, one upward and the other downward, arms fully extended My upper legs are now rock-hard powerful piston rods.
I was a lifetime DF rider and bought a bent a few years ago. The first couple of times out, I could feel the burn of muscles not used to exerting themselves. In a DF you you mostly use the muscles in the front of your legs, in a bent, you tend to use mostly the back muscles. At least that's the way it worked out for me. BTW, after a few days, the legs acclimated to the bent and life was sweet again.