Muscle movement occurs when muscles contract and relax, allowing the body to perform various actions. This process is controlled by the nervous system, which sends signals to the muscles through motor neurons. There are three types of muscles in the body: skeletal, smooth, and cardiac. Skeletal muscles are responsible for voluntary movements, while smooth muscles control involuntary actions, such as digestion. When a muscle contracts, it shortens and pulls on the attached bones, creating movement at the joints. The energy for muscle contraction comes from adenosine triphosphate (ATP), which is produced during cellular respiration. Proper coordination of muscle movements is essential for activities ranging from walking to complex sports.