I've recently started working on my legs by running on treadmills, elipticals, and stairsteppers everday at my local (small) gym. Everday I ride my bike over there after stretching, run about 2 miles on the eliptical or treadmill and then sometimes do a bit of stairstepper. I've heard however, that your muscles need good rest after working out. Does this apply to running and using machines such I have? Do I need to rest every other day before running another few miles or so?