If you're having trouble getting through a tiring variation, give yourself a little mental coaching. A recent study shows that telling yourself you're not as tired as you think you are may have a positive effect on your performance. Scientists asked fit young men and women to ride a bike to the point of exhaustion, while monitoring their power and pace. Later, the participants were split into two groups. One group continued as normal, while the other was coached in self-talk. The participants who put a positive spin on their fatigue, saying phrases like "You're doing well" in their heads, were able to ride much longer and farther than the group that didn't. How's that for mind over matter?