Functional and clinical significance of skeletal muscle architecture

Skeletal muscle architecture is the structural property of whole muscles th at dominates their function. This review describes the basic architectural properties of human upper and lower extremity muscles. The designs of vario us muscle groups in humans and other species are analyzed from the point of view of optimizing function. Muscle fiber arrangement and motor unit arran gement is discussed in terms of the control of movement. Finally, the abili ty of muscles to change their architecture in response to immobilization, e ccentric exercise, and surgical tendon transfer is reviewed. Future integra tive physiological studies will provide insights into the mechanisms by whi ch such adaptations occur. It is likely that muscle fibers transduce both s tress and strain and respond by modifying sarcomere number in a way more su ited to the new biomechanical environment. (C) 2000 John Wiley & Sons, Inc.