THE MUSCLES.
ATTACHMENT OF THE MUSCLES TO THE BONES (p. 30).—One of the two bones to which a muscle is attached is usually less mobile than the other, so that when the muscle shortens, the latter is drawn down against the former. In such a case, the point of attachment of the muscle to the less mobile bone is called its origin, while the point to which it is fixed on the more mobile bone is called its attachment….A muscle is not always extended between two contiguous bones. Occasionally, passing over one bone it attaches itself to the next. This is the case with several muscles which, originating from the pelvic bone, pass across the upper thigh bone, and attach themselves to the lower thigh bone. In such cases the muscle is capable of two different movements: it can either stretch the knee, previously bent, so that the upper and the lower thigh bones are in a straight line; or it can raise the whole extended leg yet higher, and bring it nearer to the pelvis. But the points of origin and of attachment of muscles may exchange offices. When both legs stand firmly on the ground, the above-mentioned muscles are unable to raise the thigh; instead, on shortening, they draw down the pelvis, which now presents the more mobile point, and thus bend forward the whole upper part of the body.
One important consequence of the attachment of the muscles to the bones is the extension thus effected. If the limb of a dead body is placed in the position which it ordinarily occupied during life, and if one end of a muscle is then separated from its point of attachment, it draws itself back, and becomes shorter. The same thing happens during life, as is observable in the operation of cutting the tendons, as practiced by surgeons to cure curvatures. The result being the same during life and after death this phenomenon is evidently due to the action of elasticity. It thus appears that the muscles are stretched by reason of their attachment to the skeleton, and that, on account of their elasticity, they are continually striving to shorten. Now, when several muscles are attached to one bone in such a way that they pull in opposite directions, the bone must assume a position in which the tension of all the muscles is balanced, and all these tensions must combine to press together the socketed parts with a certain force, thus evidently contributing to the strength of the socket connection….This balanced position of all the limbs, which thus depends on the elasticity of the muscles, may be observed during sleep, for then all active muscular action ceases. It will be observed that the limbs are then generally slightly bent, so that they form very obtuse angles to each other.
Not all muscles are, however, extended between bones. The tendons of some pass into soft structures, such as the muscles of the face. In this case, also, the different muscles exercise a mutual power of extension, though it is but slight, and they thus effect a definite balanced position of the soft parts, as may be observed in the position of the mouth opening in the face.—ROSENTHAL, Muscles and Nerves.
MUSCULAR FIBERS (p. 3l).—The anatomical composition of flesh is very similar in every kind of creature, whether it be the muscle of the ox or of the fly; that is to say, there are certain tubes which are filled with minute parts or elements, and the adhesion of the tubes together makes up the substance of the flesh. These tubes may be represented grossly by imagining the finger of a glove, to be called the sarcolemma, or muscle- fiber pouch, and this to be so small as not to be apparent to the naked eye, but filled with nuclei and the juices peculiar to each animal. Hundreds of such fingers attached together would represent a bundle of muscular fibers. The tubes are of fine tissue, but are tolerably permanent; whilst the contents are in direct communication with the circulating blood and pursue an incessant course of chemical change and physical renewal.—EDWARD SMITH, Foods.
FIG. 71.
[Illustration: Smooth Muscle Fibers (300 times enlarged).]
THE SMOOTH MUSCLE FIBERS consist of long, spindle-shaped cells, the ends of which are frequently spirally twisted, and in the center of which exists a long, rod-shaped kernel or nucleus. Unlike striated muscle, they do not form separate muscular masses, but occur scattered, or arranged in more or less dense layers or strata, in almost all organs. [Footnote: An instance of a considerable accumulation of smooth, muscle fibers is afforded by the muscle pouch of birds, which, with the exception of the outer and inner skin coverings, consists solely of these fibers collected in extensive layers.] Arranged in regular order, they very frequently form widely extending membranes, especially in such tube-shaped structures as the blood vessels, the intestine, etc., the walls of which are composed of these smooth muscle fibers. In such cases they are usually arranged in two layers, one of which consists of ring-shaped fibers surrounding the tube, while the other consists of fibers arranged parallel to the tube. When, therefore, these muscle fibers contract, they are able both to reduce the circumference and to shorten the length of the walls of the tube in which they occur. This is of great importance in the case of the smaller arteries, in which the smooth muscle fibers, arranged in the form of a ring, are able greatly to contract, or even entirely to close the vessels, thus regulating the current of blood through the capillaries. In other cases, as in the intestine, they serve to set the contents of the tubes in motion. In the latter cases the contraction does not take place simultaneously throughout the length of the tube; but, commencing at one point, it continually propagates itself along fresh lengths of the tube, so that the contents are slowly driven forward.
As a rule, such parts as are provided only with smooth muscle fibers are not voluntarily movable, while striated muscle fibers are subject to the will. The latter have, therefore, been also distinguished as voluntary, the former as involuntary muscles. The heart, however, exhibits an exception, for, though it is provided with striated muscle fibers, the will has no direct influence upon it, its motions being exerted and regulated independently of the will. Moreover, the muscle fibers of the heart are peculiar in that they are destitute of sarcolemma, the naked muscle fibers directly touching each other. This is so far interesting that direct irritations, if applied to some point of the heart, are transferred to all the other muscle fibers. In addition to this, the muscle fibers of the heart are branched, but such branched fibers occur also in other places; for example, in the tongue of the frog, where they are branched like a tree. Smooth muscle fibers being, therefore, not subject to the will, are caused to contract, either by local irritation, such as the pressure of the matter contained within the tubes, or by the nervous system. The contractions of striated muscle fibers are effected, in the natural course of organic life, only by the influence of the nerves.—ROSENTHAL.
OVEREXERTION AND PERSONAL IMPRUDENCE (p. 40).—Among children there is little danger of overexertion. When a little child reaches the point of healthy fatigue, he usually collapses into rest and sleep. But with youth comes the spirit of ambition and emulation. A lad, for instance, is determined to win a race, to throw his opponent in a football scramble, to lift a heavier weight than his strength will warrant; or a girl is stimulated by the passion she may possess for piano playing, painting, dancing, or tennis. The moment of exhaustion comes, but the end is not accomplished, and the will goads on the weary muscles, perhaps to one supreme effort which terminates in a sharp and sudden illness, perhaps to days and weeks of continued and incessant application, during which the whole system is undermined. Thus is laid the foundation for a feeble and suffering maturity.
To elderly people, overexertion has peculiar dangers, dependent largely upon the changes which gradually take place in the tissues of the body. The walls of the blood vessels become less and less elastic, and more and more brittle, as life advances, until at last they are ready to give way from any severe or unusual pressure. We constantly see old people hastening their death by personal imprudence. An old gentleman running to catch the morning train; an old farmer hastening to turn the strayed sheep out of a cornfield; the old sportsman having a last run with the hounds; the last pull at the oars; the last attempt of old age to play at vigorous manhood.
A prominent American physician has said that between the ages of forty and fifty every wise man will have ceased to run to "catch" trains or street cars; and that between fifty and sixty he will have permanently discarded haste of all kinds. Equal precautions should be observed by both young and old, but especially by those advanced in life, in regard to extremes of heat, cold, or storm. William Cullen Bryant, by exposing himself to a scorching sun and refusing to permit a friend to protect him with an umbrella while delivering an address in Central Park, received injuries to his system that carried him to his grave. Ralph Waldo Emerson, by standing in a chilling wind, contracted a cold and died. George Dawson, by going thoughtlessly into a freezing atmosphere from the sweltering rooms of a crowded reception, took cold which resulted in pneumonia and death. Matthew Arnold, for years a sufferer from heart difficulty, in a single instance neglected the advice of his physician not to indulge in any violent exercise, made repeated attempts and finally succeeded in jumping a fence, and in a few hours was a dead man. Roscoe Conkling braved the most terrible blizzard ever known in the east and sacrificed his life. And yet, these were all men of exceptional prudence. Probably no other five persons in the world of like surroundings and vocations were more careful of their health. In an unguarded moment their prudence left them, and they paid the terrible penalty.—Compiled.
EFFECTS OF INSUFFICIENT OUTDOOR EXERCISE UPON THE YOUNG (p. 41).—Children deprived of adequate outdoor exercise are always delicate, pale, and tender; or, in a figurative sense, they are like the sprig of vegetation in a dark, dank hole,—bleached and spindling….An inactive indoor life is one of the most effectual ways of weakening the young body. It renders the growth unnaturally soft and tender, and thus susceptible to harm from the slightest causes. It hinders the garnering of strength necessary for a long life, and gives to the germs of disease a resistless power over an organization so weak and deficient….Measles, scarlet fever, and diphtheria find among such a congenial soil, and run riot among the elements of the body held together by so frail a thread….Such children are always at the mercy of the weather. Colds and coughs are standard disorders in winter, headaches and habitual languor in summer….The scapegoat for this result is the climate: if that was only better, mothers are sure their children's health would also be better. No, it would not be better: no earthly climate is good enough to preserve health and strength under such unnatural training….Children of the laboring classes, often dirty and imperfectly clad, seldom have colds, simply for the reason that, for the greater part of the day, they have the freedom of the streets. It is not the dirt, it is not the rags, but the life-giving force of an active outdoor life that renders such children so strong and healthy. —BLACK, Ten Laws of Health.
POPULAR MODES OF OUTDOOR EXERCISE (p. 42).—Walking.—Every person has his own particular step, caused by the conformity, shape, and length of his bones, and the height of his body. Such a thing, then, as a regulation step is unnatural, and any attempt at equalizing the step of individuals of different heights must result in a loss of power.
The moment, also, that walking comes to be uphill, fatigue is sensibly increased. The center of gravity of the body is changed, and the muscular force necessary to provide for the change causes the fixing of the diaphragm, and a rigid condition of many muscles. Respiration is interfered with, owing to the fixing of the diaphragm, and the heart becomes affected thereby. A person with a sensitive or diseased heart can, during a walk, tell when the slightest rise in the ground occurs. We make climbing more exhausting from the habit we have of suspending the breath. Let the reader hold his breath and run up twenty-four steps of a stair, and then perform the same act breathing freely and deeply. It will be found that by the first act marked breathlessness will be induced, whereas by the latter the effect is much less. This management of the breath constitutes the difference between the beginner and the experienced athlete. The enormous increase of the quantity of air consumed during exercise will at once bring home a number of lessons. One is, that exercise is best taken in the open air, and not in gymnasia; another, that free play to act for the regions of the chest and abdomen must be given. On no account must a tight belt be worn around the soft-walled abdomen. If a belt is preferred to braces, let it be applied below the top of the haunch bone, where the bones can resist the pressure.
Whatever may be the pastimes indulged in by young men, walking should never be neglected. The oarsman will become "stale" unless the method of exercise is varied; the gymnast will develop the upper part of his body, while his lower extremities will remain spindleshanks. So with all other forms of exercise; success, in any form of game, sport, or gymnastic training, can not be attained unless walking be freely taken.
Skating is simply an exaggerated swinging walk, with this difference, that the foot on which one rests is not stationary, but moves along at a rapid rate. The benefit to the circulation, respiration, and digestion is even greater in skating than in walking. The dangers from skating are:
1. The giving way of the ice. Great caution should be used in regard to the safety of a frozen pond or river.
2. Taking cold from becoming overheated, and from subsequent inactive exposure. Physiological knowledge will teach people that, when they begin to skate, outer wraps should be laid aside, and again put on when skating is finished.
3. Sprains, especially of the ankle, and other minor accidents arising from falls. Ankle boots with strong uppers should be worn during skating. Those who have weak ankles ought to wear skates with ankle straps and buckles, acme skates being relegated to those who are not afraid of going "over their foot."
Rowing.—The muscles employed in rowing may be summed up under two heads—those that are used in the forward swing, and those used in the backward. In the forward swing all the joints of the lower extremity, the hip, knee, and ankle, are flexed; the shoulder is brought forward; the elbow is straightened; and the wrist is first extended and then flexed, in feathering the oar. The body is bent forward by the muscles in front of the abdomen and spinal column. In the backward movement the reverse takes place; the lower extremity, the hip, knee, and ankle are straightened; the shoulder is pulled back; the elbow is flexed; and the wrist is held straight. The body is bent backward by the muscles at the lower part of the back, and by those of the spine in general. It will be seen that the enormous number of joints put into use, and the varying positions employed, call into play nearly every muscle of the limbs and trunk. Rowing gives more work to the muscles of the back than any other kind of exercise. This is of the first importance to both men and women, but especially to women. The chief work of the muscles of the back is to support the body in the erect position, and the better they are developed the better will the carriage be, and the less likelihood of stooping shoulders, contracted chests, and the like. Now, the work of the muscles in supporting the body is largely relegated in women to the stays, and, in consequence, the muscles undergo wasting and fatty degeneration, in fact, atrophy; so that when the stays are left off, the muscles are unfit to support the body. Rowing exercises these muscles condemned to waste, and imparts a natural carriage to the girl's frame. In rowing, as in horseback riding, the clothing should be loose, stays left off, and flannels worn next the skin. The dress itself should be of woolen, and there should always be in the boat a large wrap to use when one stops rowing. The following practical rules should be observed by rowers:
1. Never row after a full meal.
2. Stop when fatigue comes on.
3. Allow the breath to escape while the oar is in the water. A novice usually holds his breath at each stroke, and pulls so rapidly that in a few minutes he becomes breathless, and is forced to stop. Not only is this uncomfortable, but it is dangerous. In the case of both young and old, it may give rise to an abdominal rupture (hernia), dilation of the cavities of the heart, rupture of a heart valve, varicose veins, etc. Instead of fixing the diaphragm and holding the breath during the time of pulling, as novices are apt to do, do exactly the opposite. Let the diaphragm go loose, and allow the breath to escape.
4. Change the clothing from the skin outward as soon as the day's rowing is finished.
5. Before retiring for the night, have a warm bath, temperature 92° Fahr. This is a specific against the aches and muscular stiffness which often follow a long pull on the water.
Swimming.—A word of warning is necessary in regard to those learning to swim in rivers. Boys at school, when they take to river bathing, often carry it to a dangerous extent. They get into the water, and now in, now out on the bank, sometimes remain for hours. This may take place day after day, and if the weather continues warm and the holidays last long enough, the boy may reduce himself to the lowest ebb of feebleness, and possibly develop the seeds of latent disease. He may even die from the effects of this prolonged immersion and madcap exposure.
The muscular exertion undergone during swimming, especially by those who swim only occasionally, is very great. The experienced swimmer conserves his strength, as do proficients at all feats, but the occasional swimmer, like the occasional rower, puts forth treble the energy required, and soon becomes exhausted. In the first place, it is a new act for the muscles to perform; they are taken off from the beaten tracks, and are grouped together in new associations; hence they lack adjustment and adaptation. Again, as in other feats for which one is untrained, the heart and lungs do not work in time. Ease and speed in swimming depend upon the attainment of harmony in the working of the muscles, heart, and lungs.
Diving is an accomplishment attached to swimming, which involves many dangers, and is well-nigh useless. The customary dive off a springboard into the shallow water of a swimming bath is dangerous in the extreme. The only place where diving should be attempted is into deep water, at least fifteen or twenty feet, where there is no danger of striking the bottom.
Lawn Tennis.—Of all modern inventions in the way of games, lawn tennis is the best.
The dangers attendant on lawn tennis are:—
1. Overexertion, causing rupture and deranged circulation, especially in the case of those with weak hearts, or those who, being out of condition, or too fat, suddenly engage in the game too long or too violently.
2. Rupture of the tendon of Achilles, from taking a sudden bound. In such an accident the subject falls down, with a sensation as if struck with a club on the leg.
3. Rupture of one of the heads of the biceps in the arm. Here the arm drops helplessly, and a muscular knob rises up on the inner and upper part of the arm.
4. The tennis arm. This trouble arises from the method of manipulating the bat. The pain is felt over the upper end of the radius.
Many of the strains, ruptured tendons, and torn muscles in tennis players are caused by the want of heels to tennis shoes. As, ordinarily, we walk on heels which vary from half an inch to an inch, there must be a considerable extra strain thrown on the muscles of the calf of the leg, when the heels are left off. Especially during a sudden spring is this apparent, when to rise from off the heels on to the toes requires a greatly increased force. Tennis shoes should therefore have fairly deep, broad heels.
Horseback Riding is a mixed exercise, partly active and partly passive, the lower parts of the body being in some measure employed, while the upper parts in easy cantering are almost wholly relaxed. It is peculiarly suited to dyspeptics, from its direct action upon the abdominal viscera, the contents of which are stimulated by the continued agitation and succussion, consequent on the motion in riding.
Bicycling and Tricycling.—While strongly recommending bicycling and tricycling to both men and women in health, those suffering from heart or lung affections, ruptures, scrofula, joint disease, or like maladies, should not indulge in them without medical sanction. For abdominal complaints, such as dyspepsia, congestion of the liver, constipation, and the like, the exercise is excellent.
Baseball is an essentially American game, which brings into play nearly all the muscles of the body. Its chief danger lies in being hit by the hard, forcibly pitched ball, and, for weak persons, in the violence of the exercise.
Football is a rough-and-tumble game, suited only to that class of boys and men, who, brimming over with animal life, take small heed of the accidents liable to occur.
Light and Heavy Gymnastics.—For wet weather, and when outdoor exercise is not practicable, gymnastics are most advisable. Boys and girls, at the age of fifteen or sixteen, often shoot up and become tall and lanky; they want filling out, and are troubled with growing pains. Even men, when tall and thin, are seldom very erect, their muscles are too weak; and there is only one way of overcoming this weakness—by exercising them. Nothing more is wanted than a pair of very light Indian clubs, a pair of light wooden dumb bells, a long wooden rod, and a pair of wooden rings,—the last for combined exercises. Indeed, a systematic motion of the body itself, without any extra artificial resistance, is quite sufficient for the purposes of physical education. In nearly all our large cities are found gymnasia, provided with competent instructors, and every facility for both light and heavy gymnastics. Exercise in a gymnasium is open to the objection of being too brief and too severe, and of simply causing an increase of muscular development. Besides, it is generally unequal in its results, being better adapted to the cultivation of strength in the upper extremities and portion of the body than in the lower. Nevertheless, during inclement weather, or with persons in whom the muscles of the arms and chest are defective, moderate gymnastic exercise is far better than no exercise.—Compiled. (Mostly from "The Influence of Exercise" in The Book of Health.)