Overview Anatomical and Physiological Fundamentals of Human Motion

Where does anatomy end and kinesiology begin? In truth, there is no answer because the question itself is not valid. One might as well ask, “Where does the study of words end and the writing of compositions (or articles, or books) begin?” or “Where does the study of building materials end and the designing and erecting of buildings begin?” Just as words are the elements used in all writing, whether creative, factual, or expository, and just as bricks, wood, cement, metal, and glass are some of the elements used in building, so bones, joints, muscles, connective tissue, blood vessels, and nerves are the vital elements of human motion. They are the essential elements used in batting a baseball, passing and carrying a football, shooting a basketball into the basket—in fact, in all running, walking, jumping, throwing, striking, catching, and swimming; likewise, one finds them in keyboarding, manual labor, painting, sewing, knitting, and so forth, almost without end.

One aim of Part I is to prepare students of human motion, whether they are in physical education, athletic training, physical therapy, occupational therapy, exercise science, or other related professions, to systematically analyze human movements in terms of muscles, joints, and nervous system integration and to apply the knowledge provided to improve performance in motor skills. This section should not be looked upon merely as a review of anatomy but as the very foundation for analysis of human motion. It demonstrates the close relationships between anatomical structure and function, and it provides a body of knowledge that can be utilized in learning and perfecting various motor skills. It aims to demonstrate how the bones, joints, and muscles serve as elements in anatomical levers, which act in accord with the laws of mechanics. It also strives to make clear the influences of gravitational and other external forces on muscular actions. For instance, under certain circumstances, these forces may cause an action to be the exact opposite of what one would expect in view of the movement that is being performed. It should be obvious, therefore, that memorizing the actions of muscles will not prepare the student to make accurate analyses. Rather, a true understanding of all the conditions that influence the functions of the muscles is necessary.

A second aim of Part I is to equip the future physical education instructor, coach, trainer, therapist, or fitness leader with the anatomical knowledge essential for understanding the nature of common injuries and their prevention or rehabilitation. For this reason, considerable emphasis is placed on the structure of each joint, the factors that contribute to its stability, and the factors that influence the range of motion of each joint. One factor that many seem to be ignorant about is the timetable of ages at which the epiphyseal cartilages become ossified. It should be of interest because it marks the turning point between the period of bone growth and the period of bone maturity. Because of the significance of this information, a schedule of the maturation age of each bone that participates in common activities has been included in the first chapter.

Part I contains eight chapters—two on the musculoskeletal system and its movements, one on the neuromuscular aspects of motion, and five on the anatomy and fundamental movements of specific segments of the body. The order in which these chapters are studied is entirely optional. Students who use this text may differ widely in their educational backgrounds. Some may already have completed courses in anatomy, possibly even including the experience of human dissection. Others may have had only brief courses and will feel the need to receive more detailed information. Still others may have had no anatomical instruction whatsoever and may expect none other than what is included in the kinesiology course. In an attempt to meet the needs of all students, whatever their backgrounds, in Part I we have presented fairly complete coverage of the aspects of anatomy that relate to movement and, at the same time, have omitted details whose relation to movement seem less significant. Hence, specific muscle attachments and innervation are not included in the main body of the text but may be found in chart form in Appendix C. On the other hand, the muscle’s line of pull and its relation to the joint at which the motion is occurring are emphasized because these are essential elements of movement.

In light of the aforementioned aims of Part I—to provide the student of human motion with the knowledge necessary for systematically analyzing human motion and applying such an analysis to the improvement of performance in motor skills, and to equip the instructor, therapist, coach, or trainer with the anatomical background for understanding the nature of athletic injuries and their prevention—it might seem that the student should wait until the entire anatomical section has been completed before attempting to analyze movement. On the contrary, the earlier the application of knowledge begins, the better. In fact, attempting to analyze basic movements according to the model presented in Chapter 1 as soon as possible serves as a stimulus to the study of anatomy. An example of this situation is given next.

Let us consider starting with the arm in its anatomical position and flexing the forearm at the elbow against the stabilized upper arm. Note that we have already defined the starting position and the movement. We could be even more specific if we wished and state whether the movement was executed quickly or slowly, and whether the movement was performed against resistance as though lifting a weight.

The next step would be to consider the joint itself. The structure of the elbow joint should be reviewed. Because it was stipulated that the movement was made from the anatomical position, it would be advisable to review the radioulnar articulations also, especially the proximal joint because of its close relationship to the elbow joint. It would be helpful to refer to Chapter 2 or Appendix A to check on the types and characteristics of these joints.

The muscles performing the movement should be considered next with an attempt made to answer such questions as the following: What muscles flex the elbow joint? How are they affected by the starting position and the position of the forearm throughout the movement? Try to discover whether the amount of resistance to this movement affects the participating muscles, but do not overstress this point. Include all the muscles that unquestionably contribute to flexion in this position without being overly concerned at this time as to whether they are “prinicipal” or “assistant” contributors. Review the section on the coordination of the muscular system (see Roles of Muscles) and try to identify those muscles serving in the capacity of stabilizers or neutralizers.

Following the procedure described in Chapter 1 throughout the study of Part I will pave the way for the later analysis of more complex movements. Procedural steps for analyzing fitness exercises, sport skills, and other physical activities are presented in Chapter 1, Components of a Kinesiological Analysis. For the present, however, it is suggested that the student make simple joint, muscle, and neuromuscular analyses until the process is thoroughly familiar.

In the following chapters, the reader may notice several references that may seem dated. Because of their continued timeliness, however, these classic works are still in use today. The seminal work by Basmajian and DeLuca, for instance, was done in 1985, but it stands today as a classic in the study of muscles and is still cited as a primary reference in current research.