A mistake many people make when cycling or spinning is only using their quads to push down. Ride more efficiently and target the back of your legs by learning to actively pull up on the upstroke with your hamstrings. Serious cyclist do this. Easier said then done but try this drill to teach yourself. Cycle one-legged for 1 minute on one leg then 1 minute on the other. Keep both feet locked in firmly to the straps while doing the drill but only actively use one leg and keep the other slack. Cycling one-legged will help teach you to pull up. Once you feel you have it, begin regular spinning but return to the drill as needed. For more trainer tips join me on Facebook.