The muscles may be used not only to produce those general influences which are necessary to the maintenance of health, but also to produce desirable special effects, among which the prevention and correction of faulty carriage and action are of great importance. In considering the use of muscular work for this purpose, our subject naturally groups itself under two main divisions: first, faults of form or carriage of the body at rest, - in other words, a bad figure; and second, faults of handling the body while it is in motion, - in other words, awkwardness or clumsiness.
The human body may be chiseled in marble or molded in bronze, and the statue thus formed may recall to the mind the shape or figure of the person it represents. But the shape of the living body is not rigidly fixed, as is that of the statue. The bony skeleton is sometimes called a framework, which supports the muscles, viscera, skin, etc. While this is to some extent true, the organs are not rigidly supported by the skeleton, as the canvas is supported by the poles and ropes which constitute the framework of a tent. In other words, the bones of the skeleton are not rigidly joined together; they do not of themselves make a self-supporting framework; the strong ligaments which pass from one bone to another simply limit or guide the movement of the bones they do not, strictly speaking, bind them together. If all organs save the bones and ligaments were removed, the skeleton would collapse. It is itself held upright by the muscles, which determine what position the bones shall have with regard to one another; and it is more correct to say that the muscles support the skeleton than that the skeleton supports the muscles.
The carriage of the shoulders well illustrates the closing statement of the last paragraph. Some people have square; while others have sloping, shoulders; in some the shoulders are held back so that the upper portion of the back is approximately flat, while in others they droop forward, thus causing the upper chest to be more or less contracted and the back "round." To some extent, these differences may be due to hereditary structure; but they result, for the most part, from causes which are largely, if' not entirely under individual control. There is little or no excuse for round shoulders in healthy people, and the marked effect of training is evident in the fine bearing of well-trained soldiers. The truth of this statement is seen when we consider how the deformity is usually acquired, the chief causes being the following.
(a) Faulty Posture. - Round shoulders are uncommon among people whose work requires an erect carriage of the body; for example, among those who carry things upon the head. With most, however, the occupations of daily life lead to bending forward over work; writing, drawing, sewing, lifting, gardening, paving, machine and tool work at once occur as examples. The trunk is held in such a position that the shoulders tend to fall forward of their own weight. This tendency is aided by the wrongly curved backs of most chairs, - which seem as if planned especially to force the shoulders forward, - and in boys, by the use of many forms of suspenders.
(b) Improper Balance in the Play of Antagonistic Muscles. - The position of the shoulders with reference to the ribs, vertebral column, and breastbone is largely dependent upon the action of several groups of antagonistic muscles, the most important of which are those of the breast and those of the back. Figures 106 (above) and 107 show the general antagonistic action of these muscles. The contraction of the (a) great breast (or pectoral) muscle pulls the shoulder forward and nearer the breastbone; the contraction of the (b) back muscles (rhomboideus, trapezius, and others) pulls them backwards and nearer the backbone. Both groups of muscles are kept in a state of sustained moderate contraction (or tone) by the nervous system; but if the back muscles relax, while those of the pectoral group remain in tonic contraction, the shoulder will be pulled forward and the back will be round. Obviously, the maintenance by the nervous system of the proper balance in the action of these and other antagonistic groups of muscles is essential to correct carriage of the shoulder.
Arrows indicate the direction of the pull, the feet serving as a fixed basis of support. The muscles A, B, H, and C keep the body from falling forward; D, E, F, and G keep it from falling backward.
|Correct and incorrect positions of the shoulder girdle.|
14. The Period of Growth Especially Favorable for the Acquisition of Round Shoulders and Other Deformities.
The length of a growing muscle is determined largely by the distance between its origin and insertion during the period of growth. The breast muscle will grow to be a longer muscle when the shoulders are held back by the back muscles than when they are habitually allowed to droop forward. In the former case, the pectorals grow to sufficient length and do not tend to pull the shoulders forward and downward; and we avoid the excessive length of the back muscles, which makes it necessary for them to take up their own slack before they can keep the shoulders in position.
The student, can now appreciate the fact that, it is in youth, during the period of growth, that deformities are most readily acquired and most easily corrected; for the muscles, the ligaments, the bones, are then in their formative stage. In the case in point, if the boy or girl holds the shoulders properly, the pectoral and back muscles of each side adjust themselves to their proper length; and the shoulders grow into the correct form, just as the sapling which is not bent nor deprived of proper sunlight grows into a symmetrical, beautiful tree. During the period of growth, then, - say up to at least the twentieth year, -we can hope to accomplish most in correcting and especially in preventing deformities. The correction and prevention of round shoulders evidently depend upon the... proper training and use of the muscles which play upon the shoulder; it is therefore a legitimate part of gymnastic training, for gymnastic training is largely the art of learning to use the muscles properly.
Where there is a special defect to remedy or prevent, special exercises are required. These are of the general character of the “setting-up” drill of the soldier, and in the case in point, we accomplish our purpose by using movements which in the first place stretch the pectorals and even overextend them; in the second place, give to the back muscles the exercise which they fail to get in our ordinary occupations, and so bring up their strength, their ability to withstand fatigue and to maintain the tonic contraction demanded of them; and which, in the third place, give us the knowledge of the correct position of the shoulders.
In explanation of the last point, we may say that when one habitually carries the shoulders properly, he feels that he is taking an awkward position when he allows the shoulders to droop; on the other hand, the man who habitually allows the shoulders to droop forward feels that he is in an unnatural position when he holds his shoulders back. This is largely because in the first case the back muscles and in the second the pectorals must be put on a stretch; it is also due to the fact that the sensations derived from the habitual posture, whether it be correct or incorrect, have impressed themselves on consciousness as signs of the normal conditions; to take any other position is to experience the feeling of something unusual or abnormal.
We learn of the position of parts of our body with reference to one another by sensations derived from the muscles, tendons, joints, etc.; and the sensations of position which result when we assume the habitual posture fix themselves in our thought as signs of the normal posture. Our practical, working idea of normal posture indeed, is nothing more nor less than our experience of the sensations of position resulting from habitual posture. The man who never carries his shoulders back really knows nothing of their correct position, because the sensations from correct posture are lacking; he knows no more about them than a man blind from his birth knows of the color of a landscape. One of the first steps in correcting this and similar faults must be to experience the muscular sensations which come from correct carriage; and the more frequently these sensations are experienced, the better does the subject become acquainted with them, the more likely are they to replace his erroneous judgment.
It is only through the sense of position that we can hope to acquire the practical working knowledge of correct carriage. What we learn by reading about the matter or by looking at pictures or statues of the correct figure is of little use; for such ideas come to us only through the eye, and we obviously cannot depend on our sense of vision to inform us whether we are carrying ourselves properly or not. We do not "see ourselves as others see us"; generally we do not "see ourselves" at all. It is only the sense of position that is capable of reminding us the instant we go wrong; and this sense can be trained properly only by actually assuming the correct posture.
We may now pass, to the consideration of the more important deformities, which it is the aim of special muscular exercises to prevent or correct.
(a) The failure to hold the neck erect (allowing it to bend forward). This results naturally from the fact that the weight of the head will do this, provided the tendency is not corrected by the proper training of the muscles of the back of the neck and trunk. The position of the head usually taken in reading, sewing, etc., is another cause of this bad habit.
(b) Round or stoop shoulders. These defects have already been sufficiently dwelt upon (see round shoulders).
(c) Too great backward (dorsal) convexity of the spine in the thoracic region, and too great forward (ventral) convexity of the spine in abdominal region. A certain amount of such curvature is normal in these regions; but there is usually a tendency to excessive curvature because of the weight of the parts of the body which the spine must support. Everyone knows that it is an effort to sit erect; and this feeling of effort comes from the fact that the spine is straightened, or rather its curvature kept normal, by the action of a rather complicated group of muscles, - the erectors of the spine. To sit, or stand, or walk erect involves the activity of these muscles; when they cease to act, the faulty curvature becomes more pronounced. Hence the value of all exercises which tend to straighten the spine, -exercises, for example, in which, while standing on the feet, we try by our own, muscular effort to make ourselves as tall as possible. They train and strengthen the muscles in question; they stretch their antagonists; just as throwing the shoulders back stretches the pectorals; and they impart to us by actual experience the sensation of being erect.
(d) Lateral curvature of the spine. When the spinal column and its attached ligaments and muscles are properly developed there is little or no lateral curvature of the spine; the two halves of the body are symmetrical with regard to the median plane of the body, although a considerable amount of bending of the spine as a whole to one side or the other is possible. It is, however, quite possible, by maintaining incorrect positions, to acquire a more or less pronounced lateral curvature in which the muscles and ligaments of the concave side become shortened, and those of the convex side lengthened. Perhaps, nothing is so responsible for all these faults of curvature of the spinal column as improper positions at the school desks, and much can be done to prevent them by properly constructed school furniture and careful attention to correct position. But, it is not wise to depend on these alone. No desk has been constructed in which correct posture can be indefinitely maintained with ease, and we have still in any case to contend with the force of gravity. Active exercises which straighten the spine should supplement the other measures. Experience has well established the fact that, the true preventive and remedy lies in movements which elongate the spine.
(e) We have elsewhere pointed out the important action of the muscles of the abdominal wall in supporting the abdominal viscera, especially those like the stomach, the spleen, and the intestine, which are suspended from the dorsal wall of the abdominal cavity. Fig. 137 will at once make clear how the relaxation or elongation of the abdominal muscles, by removing support from these viscera, permits their weight to pull unduly upon the mesentery, and so to stretch this support. It is also not improbable that the tense mesentery at times, by pressing upon thin-walled veins and lymphatics, interferes with the circulation of blood and the flow of lymph in some organs, and so leads to trouble. A pot belly is not a thing of beauty, and there is every reason for thinking it to be undesirable from the hygienic point of view. It is prevented in the first place, by every movement which prevents undue lumbar curvature of the spine, and, in the second place, by exercises of the abdominal muscles, which result in their improved tone. These, however, like all corrective exercises, must be followed up with maintenance of the correct position of the trunk.
A man or woman may possess none of the deformities noticed above, - the anatomical form of the body may conform to the best ideals, - and yet the positions and movements of the body may be awkward, inexpert, ungraceful. In other words, the muscles may be well developed, but the individual may be deficient in the power of easily coördinating their action in the accomplishment of desired ends. After what has been learned of the part which the nervous system plays in directing our actions, the brevity of any reference to this purpose of physical training will not mislead the student into thinking that it is of little importance. We have learned that the maintenance of equilibrium, when the body is at rest and when it is in motion, and the execution of complicated movements, both require training of the nervous system by use.
The range of activities for which we can train is very extensive; playing upon musical instruments, the execution of gymnastic feats on the parallel and horizontal bars, the traveling rings, or the trapeze, are only a few examples of what can be done by the training of the nervous system by practice.
A large part of gymnasium work consists in this sort of training, and there is almost no limit to the forms of exercise to which we may train, - vaulting, jumping, balancing the body on one foot while various movements are made, the tricks of the parallel and horizontal bars, trapeze, etc. Is there any principle to guide us in the choice of what we shall do? In reply to this question, we may say that the leading principle should undoubtedly be that of training for what will be useful, and while we need not discard all training which cannot be justified on this ground, that which is useful should not be sacrificed to that which is not useful. A large amount of skill is required to walk upon the hands with the feet in the air, and the thing can be done very gracefully by training; but it is certainly better to cultivate the habit of walking gracefully upon the feet. And yet, one may see professional gymnasts who are extremely graceful while performing their tricks, but whose gait is clumsy and awkward.
It is evident that by far, the greater number of our customary coördinated movements are made on the feet. Hence, the value of so-called balance exercises in the widest sense, whether they consist in the execution of difficult movements while standing on one foot or on the" walking beam," or in making a proper landing from a jump or a vault; all of them afford training of those reflexes by which we retain control of the body in motion, thus securing grace of posture and carriage.
The general purpose of training these reflexes is the same as the purpose of those exercises which correct deformities; they do for the nervous mechanism of the movement what the others do for the skeletal parts and the muscles which play upon them; they give the training of use and prevent atrophy from disuse. Both these ends, the corrective and the so-called coordinative, are best secured by the use of gymnastic movements; and the increasingly sedentary character, of much of our modern life correspondingly increases the value of gymnastic work, especially in the period of youth. It is well to learn and understand the most useful exercises, and even in adult life to have resort to them two or three times a week in order to hold fast what has been gained.
Under the conditions of city life, especially in winter time, the gymnasium is also useful in supplying general exercise in the form of running, gymnastic games, etc. It is better to seek outdoor work as far as possible for this exercise, but there are times when those living in the heart of crowded cities cannot get into the country, and outdoor exercise in town is not all that is to be desired. While there is sometimes a tendency to extol unduly the value of gymnastic work, there is equally marked ignorance in other quarters as to what the gymnasium may accomplish. Our cities are vastly better off for their Y.M.C.A. and other gymnasia, and we cannot afford to discourage any means of properly directed physical training.
Before leaving the subject of corrective and coordinative work, we may answer a question which is frequently asked: Has it, after all, any hygienic value? All will readily grant that this part of physical training has an æsthetic value, and that the cultivation of the taste for correct form and carriage in one's own person is to be commended. But is a man less healthy for being round-shouldered? The answer is that, he may or may not be less healthy. The deformity of round shoulders carries with it the lessened use of the upper ribs in breathing; and while one man or woman may escape dangerous consequences, another may not, - indeed we know does not, and it is the part of wisdom to avoid the danger as far as possible. In one, a pot belly may be consistent with perfect health, while in others it is not. One may go through life with some faulty curvature of the spine and not suffer from it; but thousands of persons have to consult physicians every year because of such faults. Many a man wears improper shoes without bad results; hundreds pay for it with flat foot and suffering which at times amounts to torture. There is not a single deformity enumerated above which may not prove a serious matter; and when it is so easy to avoid most of them, it would seem from a hygienic point of view well worthwhile to do so.
The hygienic value of corrective and coördinative work is justified, however, still more effectively on another ground. The tendency to take general exercise is directly proportional to the excellence of the neuromuscular mechanism of the body. The man who is awkward and clumsy, who can make but few movements, does not enjoy general exercise as does the man who has good control of his muscles and can make many movements. It is probably not too much to say that, a very large proportion of the people who settle down to a sedentary life with the coming of their thirty fifth or fortieth year do this because they can do so little with the body, and because exercise is consequently monotonous and distasteful. We can undoubtedly preserve more readily the love of movement for its own sake when we have a body which can move freely and easily, skillfully and joyously, than when we have one which is never so much at home as in an easy-chair or upon a soft bed; and we have shown above (see enjoyment of muscular activity) how valuable is this joy of movement to the body as a whole.
Insertion: Where a muscle is attached by its two tendons, the point of attachment against, which it usually pulls or is fixed is known as its origin, while the one it usually moves is known as its insertion. Thus the origin of the pectoral muscle is the breastbone and ribs, its insertion the shoulder and the upper arm.
Hough T & Sedgwick WT (1906). Muscular Activity (Chapter XVII), The Human Mechanism Its Physiology and Hygiene and The Sanitation Of Its Surroundings, Ginn & Company, pg 321-333.