what do you use as energy during cycling
(How Do Your Muscles Work continued) Thousands of thin spaghetti-like fibers make up muscle tissue. These fibers receive messages from the brain, causing the fibers to contract. The main muscles at work in cycling are the quadriceps and hamstrings in the upper leg, and the gastrocnemius and soleus in the calf. These muscles contract in a sequence that creates the pedaling action. The quadriceps and hamstrings do most of the work when you ride a bicycle.