Quote Originally Posted by Marco View Post
To some degree, yes, but I wonder how much cycling out of the saddle uses the hamstring muscles. The mechanism of cycling is that you are pushing downwards; there is only a small amount of backward force, over a very small (compared to running) range of motion.
The main work the hamstrings do when running is slowing down the swing leg when it goes forward. It is the quads that do most of the work, pushing us up, and to a small extent, forward, when our stance foot is behind us. So we do not move forward because our hamstrings are contracting and trying to move our stance leg backwards.