muscle anatomy muscle activity

Muscle Power

Among the many additional muscles are those of expression-small bundles of fibers around the eyes, mouth, and nose which we use to look angry or surprised, to wink, sneer, smile, frown. In the gastrointestinal system, there are voluntary muscles at the top, in the upper part of the esophagus. But in the walls of the lower esophagus as well as most of the stomach and intestines are involuntary muscles that help push food along. Actually, there are two layers of such muscles which work in concert: one, a circular layer, contracts to narrow the gastrointestinal tract; the other, longitudinal, and contracts to widen the tract again and make way for further narrowing.

Between the esophagus and the stomach, and at other points in the digestive tract, are thick muscular rings, called sphincters, which contract at intervals and can remain contracted for extended periods if necessary to regulate the flow of food and liquid. MUSCLE TONE Imagine for a moment that you have a rope fastened to a small wagon. In effect, the rope is a tendon and the wagon is a movable bone. If you pull on the rope, the wagon will move toward you. But if the rope is lying slack on the ground, you first must pull it tight before the wagon can begin to move. If the rope is kept taut, the wagon will move as soon as you pull. Most voluntary muscles of the body keep their ropes tight, so to speak. They are partly contracted at all times. Rarely, for example, does the jaw sag, and you can hold your head and shoulders erect for hours without fatigue. This ability to maintain partial contraction is muscle tone. Tone may be maintained, and the muscles prevented from becoming slack and deteriorated, by regular exercise and proper nutrition.

Major Muscles and muslce power

Since muscle fibers exert pull when they contract, they use energy. The energy comes from food supplied to them through the blood. A muscle works by converting chemical energy into mechanical energy. Actually, only about one fourth of the chemical energy is converted properly into mechanical energy; the remaining three fourths is lost as heat, raising the temperature of anyone doing strenuous work. This efficiency of 25 percent is similar to that of an automobile engine, which also loses much of its energy as heat. There have been calculations which suggest that the maximum energy output for man is about 6 horsepower and that as much as 0.5 horse- power output can be sustained almost indefinitely.

SOME MAJOR MUSCLES Skeletal muscles are of many shapes and sizes suited to their particular jobs-and they have many jobs. The sternomastoid muscles, which are on either side of the head, serve two purposes. When you nod your head, it is because both of the sternomastoid muscles contract simultaneously. You turn your head to one side or the other depending upon which of the two you contract. Among muscles at the shoulder are the trapezius, which shrugs the shoulder when it contracts, and the pectoralis major, which spreads over the chest and attaches to the humerus and helps sweep the arm across the chest. On the forearm are muscles that divide into tendons extending down to the fingertips; they help move the fingers.

 Among the big muscles of the lower extremity are the gluteal muscles on the buttocks, which, with their contraction, move you from sitting to standing position and are involved in walking; the sartorius, in the thigh, the longest muscle in the body, which pulls the thigh into cross-legged position; the quadriceps in the thigh used [or balance during standing and for kicking; and the gastrocnemius and solt'us in the calf which enable you to stand on tiptoe and provide from the ground for walking, running, dancing. Along each side of the spinal column maintain an erect posture, to bend the body, and to help turn it to one side or the other. Inside the body is the major muscle for breathing, the diaphragm, which is attached through tendons to the spinal column, ribs, and lower tip of the breastbone. The contraction of the diaphragm helps fill the lungs with air. And the diaphragm, incidentally, is also used in laughing, sneezing, and coughing. Its spasmodic contractions occasionally produce hiccupping. 

Warming And Cooling Off helps Muscles-Heart rhythm- streching-bending-excercises

WARMING UP AND COOLING OFF

Any time you are going to work out hard-when you have reached the stage where that is advisable as well as appealing to you-it is important warm up gradually first. Light warm-up-easy stretching, bending, I wishing, slow running in place-limbers up the muscles, prepares the heart and lung for exertion, and tunes up the nervous system. 

There is some controversy among athletic coaches as to whether warming up ever actually improves athletic performance, but there is evidence that it is valuable as a safety measure, a means of reducing risk of injury. As important as warming up at the beginning of a hard workout is tapering off properly afterward. During active exercising, the heart pumps blood out faster to keep the muscles supplied. And the muscles, HI they contract, produce a kind of pumping action on the veins that helps return blood to the heart and lungs.

 If you stop exercising suddenly, the heart will continue for a while to pump extra blood but the muscles, especially those in the legs, no longer dive, no longer squeeze on the veins. As a result, some pooling of blood may occur in the muscles, causing a temporary shortage elsewhere in the body, making you feel faint. Also, it appears that cramps and stiff- ness are less likely to develop if you taper off. To taper off, just keep moving about, in relaxed fashion. Instead of sitting down, walk about, lazily bend and stretch.

A few minutes of this will suffice. Do not rush into a hot tub or shower immediately after a workout or even after tapering off. Give yourself another 5 to 10 minutes to cool off. You need this time to radiate some of the heat you have worked up. If you jump right into a tub or shower, your body temperature will be above normal and the hot water will impede heat dissipation, so you will come out of the bath still sweating. 

ISO METRICS VERSUS ISOTONICS

ISO METRICS VERSUS ISOTONICS

For some years, the virtues of isometrics have been trumpeted, often in advertising which promises an isometric system that "will put you in top shape in a minute a day-and no sweat." Isometrics involve muscular contractions without movement. The sys- tem is based on the principle that when a muscle is required to work beyond its usual intensity, it will grow. In isometrics, one set of muscles may be pitted against another or against an immovable object such as a doorway or floor. 

Put your palms together and push your hands against each other as hard as you can, without moving either hand. Or push against a closed door which does not move. These are isometrics. On the other hand, isotonic involve movement. Running, lifting, push-ups, sit-ups, virtually all sports are isotonic. Isometric exercises can be useful-for example, in correcting specific deficiencies such as building arm muscles or putting back into condition a leg that has been in a cast.

They may be useful, too, as a supplement to isotonic for further development of specific major muscles and muscle areas. But it is important to realize that your objective in exercising is not simply to build muscular strength. Strength is the ability to work against a resistance. Additionally, you need muscular endurance, the ability of a muscle to respond repetitively for a relatively long period of time; flexibility or muscular elasticity so you can use the muscle effectively throughout its whole range of motion; and cardiovascular-pulmonary efficiency-the adaptive response of heart, blood vessels; and lungs to work and exercise. 

Isometrics can help develop strength. But for the other needs, you have to get down on the floor and do push-ups and sit-ups and other isotonic exercise; you have to walk and jog or swim; you have to work the muscles through their whole range and work them repeatedly; and you have to sweat at the job and give the heart and blood vessels and lungs a workout. There is no shortcut. 

Excercises and blood circulation, Physical activity Vs Excercises

The higher oxygen content of the blood will aid muscle nutrition. As circulation improves in both quality and quantity throughout the body, the total effect is admirable: Muscles are strengthened; so is the whole supporting system. It appears, too, that there may be a double defect on the heart itself: It becomes more efficient in its pumping not only during activity but at other times as well, thus reducing the strain on it at all times; in addition, it appears that activity which builds endurance also stimulates the development of new and extra blood vessel pathways to feed the heart muscle. 

Thus, if there should be trouble in the future, if a coronary artery should become choked by atherosclerosis and a heart attack occurs, that attack is likely to be less severe because of the extra circulation available. Because of the extra circulation, much less damage to the heart muscle is likely to occur, and chances of survival are greatly increased. The best activities for exercising the heart and lungs and for building endurance are those that are continuous in nature-brisk walking, jogging, swimming, for example. The effectiveness of walking is not fully appreciated by most people. It brings many muscles into play.

 It is a continuous activity. It lends itself to putting a healthy progressive load on the body. Start with a relatively easy mile walk. Gradually lengthen the walk and increase the pace. Keep doing this until, for example, you are up to a three-mile walk as fast as you can get your legs to carry you, and you are getting great benefits every step of the way. Jogging, too, has its merits, as a simple and practical aid in developing both muscular strength and endurance. It is inexpensive, requires no special skill, can be done outdoors and, in inclement weather, indoors.

Start with a jog that is only a little faster than a brisk walk. Jog until you begin to puff. Then walk. Then jog again. Your body should be upright, not bent forward. Keep the buttocks in, not protruding; the back straight, not arched; bend the elbows; breathe through nose and mouth. The objective is to start at a comfortable level and gradually exert you more and more. At first, you may jog for 50 yards, walk for 50 yards keep alternating, and cover about a mile. As you keep working till, you will find you can increase the distance, jog more and walk less.

Even perhaps interspersing some sprints, running as fast as for 50 yards, and then dropping back to a jog or walk. Over a period !11(1l1ths, you may progress until you can cover as much as three miles at a good pace, walking very little of the time. Be sure you obtain your doctor's approval before you start jogging as an exercise. 

Who need excercises? - How muscle activity helps?

DO YOU NEED EXERCISE?

The chances are that, like most of us, you are getting too little daily exercise. If you need specific clues to the fact that you can benefit from more activity, here are some: heart pounding or hard breathing after relatively slight exertion; a long time required for your heartbeat to return to normal after heavy exertion (you can measure the heart rate by the wrist pulse); stiffening of legs and thighs after climbing stairs; aching muscles after such activities as gardening or furniture moving; waking up from sleep as tired as before; frequent restlessness. 

Your physician, as part of his preventive medicine program for you, will be glad to determine with you, on the basis of your specific present condition, daily activities, and other personal factors, whether you need more exercise, how much time you need to devote to it, what kinds of activities would be best suited for you.

OPPORTUNITIES FOR ACTIVITY

Undoubtedly you will benefit from a soundly planned regular exercise schedule, even if it occupies no more than just a few minutes a day- and more on this shortly. Along with such a schedule, you can, and should, find other opportunities for increasing your activity. For one thing, it is possible to find opportunities for physical recreation that can supplement scheduled exercises and provide enjoyment. The list is almost endless: fishing trips, family outings, evenings of dancing, bowling in an office or neighborhood league, walking, etc. 

For another thing, there are opportunities for stepping up daily activities-and little bits of action add up in their good effects. It's a matter of attitude, of recognizing that it is good to use the body As much as possible and of seeking chances to do so.

Walk up a flight Physical Activity in 85 or more of stairs instead of relying entirely upon the elevator; walk part III much or sometimes all the way to the market, to the office. Interrupt sedentary work with little bursts of activity, even if no more than getting lip out of the chair and bending, stretching, moving about, flexing the  squatting, imitating a few golf swings.