Flexure

“ But in life, that fabric of struts is surrounded and interwoven with a complicated system of ties: ligament and membrane, muscle and tendon, run between bone and bone; and the beauty and strength of the mechanical construction lie not in one part or in another, but in the complete fabric which all the parts, soft and hard, rigid and flexible, tension-bearing and pressure-bearing, make up together618. ”

“ The equilibrium of nature is constantly preserved; for in walking, leaping, running, &c., similar precautions are taken. By the flexibility of our bodies in striking, according to the proportionate force meant to be employed, the body is first drawn back, then the limb propelled forward, bringing with it the weight of the body. ”

“ But the moving body, ever tending to fall, needs constant support, if it is to move in a true horizontal line. 'What, then,' he asked himself, 'will give constant support to a moving body?' And his answer was 'Human legs!' That was the discovery that immortalised his name! ”

“ Whatever may be the cause of the superiority of the flexors, the fact cannot be doubted. 1st. In hysterical convulsions, in those of infants, in all the spasmodic motions in which the will has no part, the contractions take place much more in the direction of flexion than in that of extension. 2d. In old people the flexors finally become superior to the extensors; for example, the fingers and toes are almost uniformly bent. ”

“ The extent of the leap in height, or horizontally, is proportioned to the power employed, and the practice acquired. As it is performed with facility only in proportion to the strength exerted, and the elasticity and suppleness of the articulations and muscles of the lower extremities, much exercise is necessary to attain that degree of perfection which lessens all obstacles, and supplies the means of clearing them without danger. ”

“ I. ATHLETIC GAMES AMONG THE HOMERIC HEROES. BY EDWARD M. PLUMMER, OF BOSTON.
Few kinds of labor develop the body in a symmetrical manner. This is true even in an elementary division of labor. The carpenter and the blacksmith usually have strong, large shoulders and arms, but small and weak legs. The farmer, from excessive bending over his work, loses, in a greater or less degree, his elasticity of body, and often becomes stoop-shouldered. ”

“ To begin with, I shall draw a man such as lads draw on walls, a line for each arm, another for each leg, with the fingers longer than the arm. Long after, one or other of us will notice this lack of proportion; we shall observe that the leg is thick, that this thickness varies, that the length of the arm is proportionate to the body. In this improvement I shall either go side by side with my pupil, or so little in advance that he will always overtake me easily and sometimes get ahead of me. ”

“ Direct Flexion.—Direct flexion is the concession the head and lower jaw of the horse make in the vertical plane of the axis, of the horse when the action of the reins arrests the extension of the neck. The giving of the neck is confined to the upper portions; the front line of the face is made to approach a vertical line and the head is made to make in an almost imperceptible manner a movement analogous to a nod. ”

“ Let us remember that there are two sets of muscles, acting in unison with each other, to produce the various motions; they are known by the general terms of flexors and extensors; the first enable us to bend the limbs, the other to bring the limbs back to their former position. The flexors enable us to close the hand, the extensors to open it again. The flexors enable us to raise the foot from the ground ”

“ View from living room to hall in a city apartment. Interior woodwork, mantel, and furniture are of wood in tones which range from the dark chest to the blond chair.
A room, or a group, is in balance when it appears to be at rest; that is when the total imaginary weight, or pull, on the attention, of everything on one side of a center appears to the mind to equal the total weight of everything on the other side. An accurate feeling for balance can be acquired easily by experiment and practice. There are two kinds of balance: Even or formal, known as bisymmetric balance ”

“ And every bone in our body is a triumph of engineering architecture. No engineer could better recognize the direction of strain and stress, and arrange his rods and columns, arches and buttresses, to suitably meet them, than these problems are solved in the long bone of our thigh. ”

“ We have a system of levers to do our walking with, and they act precisely as do all levers. One leg is a lever to pry the body over the other leg, and the latter becomes a pendulum and swings back by force of gravity. ”

“ Now one of the hindmost legs closes in to the body, while all the others hold on—now another, and another, each in their turn; and by this skilful manoeuvre they have contrived to advance the body nearly an inch along the ceiling. One of the foremost legs advances again, and they proceed as before. ”

“ Every building must have a foundation and a frame of some kind to make it strong and give it shape. It is the same with the house we call our body. The frames of houses which men build are made of wood or iron; but the framework of the body is built of bones. Perhaps you have noticed that in the frames of buildings some pieces of timber are short, and some are long, and they are cut into many different shapes and sizes. So it is with the bones of the body. ”

“ We admire the mechanism of a joint, and then invent clothing which shall deprive it of its play, and ourselves of its use! Here nothing interferes with the freedom of the limbs, or disturbs the mechanism of the frame and its action. It is plastic to the hand, to relax or gird, as the occasion may require. ”

“ The frame of a house divides it into rooms, and on it are fastened the boards, laths, and shingles. In the house in which we live the flesh is fastened to the bones, and the whole is covered with skin. This framework also protects the curious rooms inside the trunk of the body. The largest bone in our frame is the leg bone, which reaches from the hip to the knee. ”

“ Flexion and Extension.—The muscles are, for the most part, so arranged in pairs, or corresponding sets, that when motion is produced in one direction by one set, there is, opposite to it, another muscle, or group of muscles, which brings the limb back to its place. When they act alternately, a to-and-fro movement results. When a joint is bent, the motion is called flexion ”

“ As a general rule, all cramped positions that are a necessary condition of labour, if they surpass the limits of resistance and elasticity of the human frame, and especially if they operate during periods of life when the skeleton is in process of formation, result in deformities, and when the skeleton is deformed, the internal organs and hence the general functional powers of the whole organism, suffer even greater alteration. ”

“ When the structure has yielded, the same inertia becomes a condition of its comparative permanence in the new form, and of the new habits the body then manifests. Plasticity, then, in the wide sense of the word, means the possession of a structure weak enough to yield to an influence, but strong enough not to yield all at once. ”

“ A foundation was there­fore necessary upon which the whole superstructure of the clothing could be reared, and by which the weight might be distributed equally upon every part of the frame; and in the second place we have often to hide defects, and not unfrequently to give support in cases of spinal deformities—stooping of the body or twist of the shoulders when debility or habit have impaired the natural erect and grace­ful attitude which the perfectly-developed frame should always assume. ”

“ The flexion is similar in the case of the multipeds; only that the legs in between the extreme ends always move in a manner intermediate between that of those in front and those behind, and accordingly bend sideways rather than backwards or forwards. ”

“ It is not the flexor muscles themselves which tire out, for these, when under fatigue of the flexion-reflex they contract no longer for that reflex, contract in response to the scratch-reflex which also employs them. ”

“ So I have seen a strong man chained down to his chair, prevented from stepping over a stick on the floor, or obliged to remain almost doubled upon himself in a stooping position, by the assurance that he could not move. On the other hand, an extraordinary power may be called forth in any set of muscles—as in hypnotized subjects—by the assurance that the action to be performed by them may be executed with the greatest facility. ”

“ B. Nature employs this kind of lever in the structure of the human frame. In lifting a weight with the hand, the lower part of the arm becomes a lever of the third kind; the elbow is the fulcrum, the muscles of the fleshy part of the arm, the power; and as these are nearer to the elbow than to the hand, it is necessary that their power should exceed the weight to be raised. ”

“ But when walking, the center of each half body is in the center of each leg, for by each step one leg makes the whole body must throw itself upon the center of the other leg, or else the body would tumble over. ”

“ There are three phases in this natural development: Angular, circular and spiral. The human form poised squarely on both feet is the spiral, the head a convexed curve, the body a concave curve, and the legs a convexed curve, like a wave line. To preserve this spiral line of changing curves, the weight is always thrown against the strong side so as to develop the weak side and maintain an equilibrium. Standing should be principally upon the balls of the feet, and the exercise should be to incline the body to and from the opposite curves. ”

“ Any one who sits down, say upon a window-ledge or a basket, is fined, and this perpetual upright position, this constant mechanical pressure of the upper portions of the body upon spinal column, hips, and legs, inevitably produces the results mentioned. ”

“ We find the principle springing to life again in the fountain jet, and symbolical of life as it has ever been; by means of the same principle applied to construction the Gothic architects raised their beautiful vaults, and emphasized the structural principle and the beauty of recurring line by moulding the edges of their ribs; while we have but to look at the structure of the human frame to find the same principle there also, in the fibres of the muscles, for instance, the radiation of the ribs, and of the fingers and toes. ”

“ To get a clearer idea of the general plan on which the body is constructed, let us imagine its division into perfectly equal parts, one the right and the other the left, by a great knife severing it through the median, or middle line in front, backward through the spinal column, as a butcher divides an ox or a sheep into halves for the market. ”

“ For, if the height of the capitals is greater than their width—when they are called "high-tensioned,"—something should be taken from the arms, so that the more the tension is weakened by height of the capitals, the more the strength of the blow is increased by shortness of the arms. ”

“ Thus I once discovered to my astonishment in a gymnasium that the extremely mechanical action of putting up a heavy weight from the ground to the shoulder and from the shoulder to the full reach of the arm above the head, became much easier after a little practice, although my muscles had not grown, nor my strength increased during the time. ”

“ Every ounce of elastic force in the great, muscular frames was called into action, and there was a profusion of strange, strong language that literally made my flesh to creep, and my hair to stand on end. ”

“ Thus, as a general result of these evolutionary principles, we obtain a body of horizontal shape, supported upon four limbs, and reduced in weight and in elongation so as to give it the best possible control of its motions, and the greatest agility consistent with its necessary gravity. ”

“ Now this has an important bearing on the problem we are going to investigate, for the weight of our body falls on the foot, so that only about one-third of the lever—that part of it which is formed by the heel—projects behind the point on which the weight of the body rests. ”

“ Before we leave this subject of mechanical adaptation, let us dwell once more for a moment upon the con­si­de­ra­tions which arise from our conception of a field of force, or field of stress, in which tension and compression (for instance) are inevitably combined, and are met by the materials naturally fitted to resist them. It has been remarked over and over again how harmoniously the whole organism hangs together, and how throughout its fabric one part is related and fitted to another in strictly functional correlation. ”

“ We consider the structure of the human extremities, and enlarge upon the flatness of the foot, and the flexibility of the hand. The one is subservient to the erect posture, the other to the innumerable manipulations which human industry demands. ”

“ I can't begin to tell all the secrets of the curls and puffs, and reinforcements, hygienic rolls, transformations, fluffy puffers, and all that, or of the complexions. Why, you can choose a complexion, like wall-paper or upholstery. They can make you as pale as a sickly heroine or they can make you as yellow as a bathing girl. There is nothing they can't do. ”

“ For, in the first place, all composite things must have a system, or arrangement of parts, so that some parts shall depend upon and be grouped round others, as in the articulation of a skeleton and the arrangement of muscles, nerves, tendons, etc., which are attached to it. To meddle with the skeleton is like taking up the street, or the flooring of one's house ”