I know ultimately you have to put your body in the position where it is most comfortable (my goal is comfort, not doing tons and tons of miles right now). But what is the general "rule" regarding whether or not to relax or tense up your muscles in your back, shoulders, neck and arms? I think I am pretty tense on my bike - just happens, think I'm always just a little nervous on it. Is it better for your body to try to relax the muscles that are not needed to pedal and stay upright?