Speaking as a former bike racer, cycling does not build muscles unless you are already wildly out of shape. Pedaling in a tall gear still isn't much resistance,

Speaking as a former bike racer, cycling does not build muscles unless you are already wildly out of shape. Pedaling in a tall gear still isn't much resistance, typically less than body weight. Muscle is built only by getting near the limit of musclular strength. Cycling only challenges your cardiovascular system. I always squatted and deadlifted to get better at sprints. Other racers who were climbing specialists had skinnier legs than the average man, yet they could climb hills incredibly fast.