Muscle Mechanics and Biochemical Kinetics

Abstract

It is now generally accepted that contraction of striated muscle occurs when the thin, actin-containing, and the thick, myosin-containing, filaments slide past each other while the length of both types of filaments remains constant (Huxley and Hanson, 1954; Huxley and Niedergerke, 1954; see Chapter 1). To form a theory of muscle contraction, the mechanism has to be defined which drives this sliding process, leading to muscle shortening at maximum speed when the actin and myosin filaments are allowed to slide freely past each other (unloaded isotonic contraction) or leading to development of maximum force when sliding of filaments is prevented (isometric contraction). Of the many proposed processes that are able to generate force or motion between two interdigitating sets of filaments (for a detailed discussion see Huxley, 1974, 1980), the crossbridge theory of muscle contraction (A. F. Huxley, 1957; H. E. Huxley, 1969) has received general acceptance.