Muscle

      Muscle is a contractile form of hankie. It is one of the four main tissue types, the other three being epithelium, connective hankie and nervous hankie. Muscle contraction is used to move parts of the body, as well as to move substance within the body. The strongest human muscle Depending on what meaning of "strongest" is used, many dissimilar muscles in the human body can be characterized as being the "strongest."

      In ordinary parlance, muscular "strength" usually refers to the ability to exert a force on an external object—for example, lifting a weight. By this definition, the massager or jaw muscle is the strongest. The 1992 Guinness Book of Records the achievement of bite strength of 975 lobs (4337 N) for two seconds. What distinguishes the massager is not anything special about the muscle itself, but its advantage in working against a much shorter lever arm than other muscles.

      If "strength" refers to the power exerted by the muscle itself, e.g. on the place where it insert into a bone, then the strongest muscles are those with the largest cross-sectional area at their belly. This is because the worry exerted by an individual skeletal (striated) muscle fiber does not vary much, either from muscle to muscle, or with length. Each fiber can exert a force on the order of 0.3 micrometers. By this definition, the strongest muscle of the body is usually said to be the Quadriceps femora’s or the Gluteus maximums.

      Again taking strength to mean only "force" (in the physicist's sense, and as contrast with "energy" or "power"), then a shorter muscle will be stronger "pound for pound" (i.e. by weight) than a longer muscle. The uterus may be the strongest muscle by weight in the human body. At the time when an infant is delivered, the human uterus weighs about 40 oz (1.1 kg). During childbirth, the uterus exerts 25 to 100 labs (100 to 400 N) of downward force with each contraction.

      The exterior muscles of the eye are conspicuously large and strong in relation to the small size and weight of the eyeball. It is regularly said that they are "the strongest muscles for the job they have to do" and are sometimes claimed to be "100 times stronger than they need to be." Eye movements, however, are and almost certainly "need" to be exceptionally fast.

The mysterious statement that "the tongue is the strongest muscle in the body" appears frequently in lists of surprising facts, but it is difficult to find any definition of "strength" that would make this statement true. Note that strictly the tongue consists of sixteen muscles, not one. The tongue may possibly be the strongest muscle at birth.The heart has a claim to being the muscle that performs the largest quantity of physical work in the course of a lifetime.

       Estimates of the authority output of the human heart range from 1 to 5 watts. This is much less than the maximum power output of other muscles; for example, the quadriceps can produce over 100 watts, but only for a few minutes. The heart does its work continuously over a whole lifetime without pause, and thus can "outwork" other muscles. An output of one watt incessantly for seventy years yields a total work output of 2 to 3 ×109 joules.