When you're pedaling away in spin class, save the upper body sway for a rock club. The motivational music may move you, but don't waste your energy rocking to the beat. Focus your energy into your legs, because as you crank the resistance on the wheel your legs are going to need all the help they can get. Holding your torso steady, and focus on your low abs to really work your core too. Better to be rock solid than to rock out!