The Muscles : Part 2

Hygienic Physiology: with Special Reference to the Use of Alcoholic Drinks and Narcotics
by Joel Dorman Steele, Ph.D.

(Page 3 of 13)

The nearer the power is applied to the resistance, the more easily the work is done. In the lower jaw, for example, the jaw is the weight, the fulcrum is the hinge joint at the back, and the muscles on each side are the power. They act much closer to the resistance than those in the hand, since here we desire force, and there, speed.

The Enlargement of the Bones At The Joints not only affords greater surface for the attachment of the muscles, as we have seen, but also enables them to work to better advantage. therefore, in Fig. 20 it is evident that a muscle acting in the line f b would not bend the lower limb so easily as if it were acting in the line f k, since in the former case its force would be about all spent in drawing the bones more closely together, while in the latter it would pull more nearly at a right angle. Therefore the tendon f, by passing over the patella, which is itself pushed out by the protuberance b of the thigh bone, pulls at a larger angle and so the leg is thrown forward with ease in walking and with great force in kicking.

How We Stand Erect. - The joints play so easily, and the center of gravity in the body is so far above the foot, that the skeleton can not of itself hold our bodies upright. Therefore it requires the action of many muscles to maintain this position. The head so rests upon the spine as to tend to fall in front, but the muscles of the neck steady it in its place. The hips incline forward, but are held erect by the strong muscles of the back. The trunk is nicely balanced on the head of the thigh bones. The great muscles of the thigh acting over the kneepan tend to bend the body forward, but the muscles of the calf neutralize this action. The ankle, the knee, and the hip lie in nearly the same line, an. Therefore the weight of the body rests directly on the keystone of the arch of the foot. So perfectly do these muscles act that we never think of them until science calls our attention to the subject, and yet to acquire the necessary skill to use them in our infancy needed patient lessons, much time, and many hard knocks.

How We Walk. - Walking is as complex an act as standing. It is really a perilous performance, which has become safe only because of constant practice. We see how violent it is when we run against a post in the dark, and find with what headlong force we were hurling ourselves forward. Holmes has well defined walking as a perpetual falling with a constant self-recovery. Standing on one foot, we let the body fall forward, while we swing the other leg ahead like a pendulum. Planting that foot on the ground, to save the body from falling farther, we then swing the first foot forward again to repeat the same operation.

The shorter the pendulum, the more rapidly it vibrates; and so short- legged people take quicker and shorter steps than long-legged ones. We are shorter when walking than when standing still, because of this falling forward to take a step in advance.

In running, we incline the body more, and so, as it were, fall faster. When we walk, one foot is on the ground all the time, and there is an instant when both feet are planted upon it; but in running there is an interval of time in each step when both feet are off the ground, and the body is wholly unsupported. As we step alternately with the feet, we are inclined to turn the body first to one side and then to the other. This movement is sometimes counterbalanced by swinging the hand on the opposite side.

The Muscular Sense. - When we lift an object, we feel a sensation of weight, which we can compare with that experienced in lifting another body. By balancing it in the hand. The muscular sense is useful to us in many ways. It guides us in standing or moving. We gratify it when we walk erect and with an elastic step, and by dancing, jumping, skating, and gymnastic exercises.

Necessity of Exercise. - The effect of exercise upon a muscle is very marked. By use it grows larger, and becomes hard, compact, and darker-colored; by disuse it decreases in size, and becomes soft, flabby, and pale.

Violent exercise, however, is injurious, since we then tear down faster than nature can build up. Feats of strength are not only hurtful, but dangerous. Often the muscles are strained or ruptured, and blood vessels burst in the effort to outdo one's companions.

Two thousand years ago, Isocrates, the Greek rhetorician, said: "Exercise for health, not for strength." The cultivation of muscle for its own sake is a return to barbarism, while it enfeebles the mind, and ultimately the body. The ancient gymnasts are said to have become prematurely old, and the trained performers of our own day soon suffer from the strain they put upon their muscular system. Few men have sufficient vigor to become both athletes and scholars. Exercise should, therefore, merely supplement the deficiency of our usual employment. A sedentary life needs daily, moderate exercise, which always stops short of fatigue. This is a law of health.

No education is complete which fails to provide for the development of the muscles. Recesses should be as strictly devoted to play as study hours are to work. Were gymnastics or calisthenics as regular an exercise as grammar or arithmetic, fewer pupils would be compelled to leave school on account of ill health; while spinal curvatures, weak backs, and ungraceful gaits would no longer characterize so many of our best institutions.

Time For Exercise. - We should not exercise after long abstinence from food, nor immediately after a meal, unless the meal or the exercise be very light. There is an old-fashioned prejudice in favor of exercise before breakfast - an hour suited to the strong and healthy, but entirely unfitted to the weak and delicate. On first rising in the morning, the pulse is low, the skin relaxed, and the system susceptible to cold. Feeble persons, therefore, need to be braced with food before they brave the outdoor air.

What Kind of Exercise To Take. - For children, games are unequaled. Walking, the universal exercise, is beneficial, as it takes one into the open air and sunlight. Running is better, since it employs more muscles, but it must not be pushed to excess, as it taxes the heart, and may lead to disease of that organ. Rowing is more effectual in its general development of the system. Swimming employs the muscles of the whole body, and is a valuable acquirement, as it may be the means of saving life. Horseback riding is a fine accomplishment, and refreshes both mind and body. Gymnastic or callisthenic exercises bring into play all the muscles of the body, and when carefully selected, and not immoderately employed, are preferable to any other mode of indoor exercise.