Scientists have studied the body for hundreds of years. Each part has been carefully dissected (cut away from the body). Some researchers use electrodes on live subjects to test out each muscle. This helps define what actions muscles are responsible for.

Combining muscle testing equipment with computers has given us a lot of new information. Computer software has been designed to analyze muscle movement and function. Some muscles are divided in parts. Each section has its own job. This kind of testing makes it possible to compare one part of the muscle to another.