When it comes to exercise, whether we are a couch potato just getting started, are already an elite athlete or fall somewhere in between, in our efforts to push through barriers, our mind is often challenged as much as our body. To progress to the next level, we are taught to tap into willpower: “just one more rep” or, “run just a little further,” “go just a little longer.” The problem with this approach is that willpower is a limited resource. If we pull on it every time we