The Golgi tendon organ / apparatus is located where muscle fibers of skeletal muscle meet tendons. Made up of strands of collagen, the organ also contains nerve tissue. The major function of the Golgi tendon organ is to sense muscle tension when a muscle is contracted, sending signals to the brain about how much force is being exerted and where. The above information is from. http://www.wisegeek.com/what-is-the-golgi-tendon-organ.htm