The muscles comprise about 40 percent of body weight. They convert chemical energy into force and mechanical work. Movement is one of the main functions performed by 620 muscles in the body. They also help maintain proper posture and produce a large portion of body heat. There are 30 other muscles that perform functions such as moving food through the digestive system, circulating blood and operating other internal organ.
Connective tissue consists of ligaments and tendons, which connect muscles and bones.
Factors in Structural Health Calcium if the most abundant mineral in the body, comprising 1.5-2 percent of an adult's body weight. But calcium deficiency in the U.S. is not as rare as might be expected in a modern nation. The Department of Agriculture lists calcium as one of the four nutrients most missing in the American diet. The body is constantly using calcium from the diet to replace old bone tissue with new tissue. When the calcium supply in the blood is low the body takes calcium from the bones without replacing it, causing them to become weak and porous.