Warming up is incredibly important. It plays several different roles: first, it allows the temperature of the muscles to begin rising as they loosen up. Second, it prepares the body for strenuous exercise. Third, it prepares the mind for strenuous exercise. Plus, of course you get to feel better as you get into training when you're warmed up. Precursor is a total body warm up designed to help you limber up so you're truly ready for action.
Extra Credit: 1 minute rest between sets.