3. The Three Major Categories Of Exercise
3.1 Contraction Exercises
Unlike the aerobic and stretching exercises, when we talk about contraction exercises we are considering primarily the development of muscular strength and endurance. Muscular strength refers to the amount of force that one can generate in an isolated movement of a single muscle or group of muscles. The greater the muscular strength of an individual, the greater the amount of force he or she will be able to generate. Muscular endurance refers to the amount of time an individual can perform a particular contraction of force, i.e., how many sit ups, push ups, curls, etc. Muscular endurance involves a specific muscle or group of muscles, unlike cardiorespiratory endurance, which involves the total body.
Muscular strength and endurance can be developed by any one or combinations of three different modes of physical contraction exercises. These forms are termed isometric, isotonic and isokinetic contractions.
Isometric training involves muscle contractions against a resistance, greater than the force that can be applied where no movement of body parts takes place. Pushing against a sturdy wall or a parked car results in contractions of the muscles involved, but will not lead to any perceptible movement of the body or the objects involved. Numerous exercises can be devised simply by applying force by different parts of the body upon common objects around the house as a source of resistance.
Isotonic training involves the actual movement or lifting of a steady resistance through the range of motion of the various joints involved. A classic example of isotonic exercise is the lifting of weights.
Isokinetic training involves a constant speed of movement against a variable resistance. The strength of a muscle varies at different angles as a result of change in the angle of pull and perspective leverages.
Thus when we lift a constant resistance, the muscle is not exercised to the same extent at the middle of its motion as it was at the beginning. In other words, if we are curling a 50-pound weight, the closer we come to completing that curl, the stronger the muscle becomes. During isokinetic training, the resistance changes to match the strength of the muscle at each point in the range of motion.
Research has shown that each of the three forms of strength-training procedures produce substantial increases in strength, power and muscular endurance. In comparing the different forms as to which offers the most complete program, very little has been written on isokinetics. This is due to the fact that it is a relatively new science and is not totally understood., So, most of the comparison is between the isometric and isotonic procedures, and is as follows:
- Both isometric and isotonic produce substantial gains in muscular strength, with many studies indicating that isotonic exercises provide the greater gain.
- Both muscular endurance and recovery from muscular fatigue is faster in muscles that have been trained isotonically.
- Isometric procedures develop strength only in limited portions of the total range of motion, whereas isotonic procedures produce a more uniform development in muscle strength.
- Isometric procedures involve no joint movements and can be safely and effectively used during the period of recovery from injury in order to prevent substantial loss of muscle size and function.
As mentioned earlier, research on isokinetic training is limited. However, a major advantage to this form of training over the other two forms is in the area of rehabilitation. Isokinetic exercise allows the muscle to exercise through a full range of motion with varying degrees of resistance. The resistance will depend on the strength of the the muscle at different angles in the range of motion. Although more research needs to be undertaken, isokinetic procedures appear to be just as effective as either isotonic or isometric—perhaps even moreso.
As Hygienic practitioners you should keep in mind that while contraction exercises are extremely beneficial in muscle strength and endurance, these procedures do very little for the development of the rest of the systems in the body. In fact, without balancing the contraction exercises with aerobics and stretching, these procedures could even be harmful. Keep in mind strong muscles and a weak heart do not make for a good combination. Develop exercise programs that utilize contraction training one day, aerobics and stretching the next. In this way you will be utilizing different areas daily while allowing other areas a chance to recover.
Along with the other two categories of exercise, stretching is of crucial importance. Regardless of how superb and strong a physique may appear, without proper extension and stretching of the muscle groups, there will be an imbalance of posture. Additionally, there may be a muscle-bound disequilibrium which could deter the overall well-being and mental poise of the individual.
Stretching should be done in a slow, static manner. The body itself provides necessary weights and counterweights through a variety of balanced static postures. Stretching postures must maintain proper vertebral extension. If done correctly, stretching brings steadiness, health and lightness to the limbs. A thorough stretching program exercises every muscle, nerve and gland in the body. It secures a fine physique which is strong and elastic without being muscle-bound. In turn, stretching postures reduce mental and physical fatigue and soothe the nerves. Only when the body is fit and flexible can it serve as a vehicle of mental poise. Physical abuse and bodily disuse result in atrophy and dysfunction of the delicate mind-body interactions that lend us the ability to live and function in a constant state of total well-being.
Flexibility can be defined as the range of possible movement without a joint or a sequence of joints. A study (Kras, H.1972) done on several hundred adults who had complaints of chronic lower back problems revealed that approximately 80% had severe muscle weakness and joint inflexibility diagnosed as the cause, while only 20% had a specific anatomical disease or lesion as the cause. Thus, there is an obvious tendency in our society to neglect the body through lack of physical exertion including stretching and flexibility exercise.
Following is a summary of some recent research done on flexibility and exercise. (H.H. Clarke, 1975-76). There is little agreement among researchers with regard to the definition and limitations of “normal” flexibility. Flexibility is highly specific and varies for each joint or joint group. Thus, the flexibility of certain joints cannot be used to generalize the flexibility of other areas of the body. Although specific data is not available, there is a relationship between flexibility measures and differences in sex and age. Although flexibility can be increased with persistent exercise, the magnitude of increase is a very individual matter and is dependent upon the specific types and forms of activity. The connective tissues primarily responsible for resistance to movement include muscle,
ligaments, joint capsules, and tendons. (These terms are sufficiently defined in the definition section.)
Research, logic and experience indicate that stretching exercises are effective in improving flexibility. Although many athletes and physicians still view such tragedies as muscle pulls, tears and strains as inevitable within a heavy exercise program, there is a growing awareness that these injuries are not accidental and can be predicted and thus prevented. Many of the top professional football teams (i.e., Steelers, Broncos, Redskins, etc.) now employ “flex” coaches to direct the players in stretching exercises. This is a prevention against injury.
An important factor to remember while incorporating a stretching routine into your daily exercise program is not to stretch or strain beyond a “pleasant tension.” There will be/some discomfort initially, due to the trauma of the stretch to the unconditioned muscles, but the pain will most likely be in the form of a nagging ache or dull pull. “Pleasant tension” refers to a slight, dull discomfort of the muscle as a whole, with no accompanying sharp or burning sensations. When there is a sharp localized sensation in the ligament, back off; this is more than “pleasant tension.” In other words, stretch just beyond what is comfortable. It is important not to hold tension while stretching; this defeats the purpose. Stretching, like all other forms of exercise, is a release. While holding a stretching posture, if you feel tension in a specific area, concentrate on relaxing that area, and releasing that tension. One should not hold the breath while stretching; instead, breathe normally. Oftentimes an exhalation is conducive to the release of tension. One other important point about tension: Don’t hold tension in your face. There is a tendency while releasing tension from the legs, back, arms, abdominal region, etc., to transfer the tension and sensation of discomfort to the face. Thus, often times one may find oneself with a furled brow, squinted eyes and clinched teeth. Let this tension go, along with the rest of it.
Stretching should be slow, consistent, sustained and static. Stretching should not be ballistic. Dr. Herbert deVries, Ph.D, lists some advantages of static stretching exercises:
There is less danger in going beyond the safe limits of stretching when doing static exercise because the exerciser moves into the position slowly and stops before harm is done. With ballistic exercises, the exerciser may realize too late that he or she has passed the limit. Also, the energy costs for slow, static stretching is lower than for rapid ballistic stretching, so the exercises aren’t as tiring to the athlete.
Furthermore, static stretching tends to relieve muscle soreness, while ballistic exercises may cause severe muscle soreness. Thus, it is recommended, when integrating stretching into your exercise program to increase your overall flexibility, be consistent and static in your movements. Listen to your body as you flow into the postures, never letting the tension accumulate, but rather relax into the stretch. Your body will let you know what your individual “pleasant tension limit” is, and don’t take the stretch any further. You will not achieve the extreme position of the stretching posture overnight. It takes persistence, patience and cautions.
As Hygienists, we want to improve our level of vitality, strength, and endurance and then maintain it. If a person is overly tense or unable to sleep, their vitality and endurance will decrease. Conversely, when tension and stress cease, vitality increases. Stretching enhances the quality of life by giving us flexibility and endurance while enhancing our mental poise. We were born with a potentially wide range of motion; however, many people are caught in the laziness of today’s society and do not use but rather abuse their potentials of strength, endurance, aerobics and range of motion. The high quality of life that is available to all of us thereby is reduced to laziness. Through exercise and the other requirements of Hygienic living we gain our health. Health is not a commodity which can be purchased with money. Instead it is an asset to be gained by hard work and proper living practices.
3.4 Aerobic Exercise
A wild cat, such as a tiger, lion, cougar or panther, stretches, runs, leaps, etc. every day. It is trim and vital and has an incredible endurance level. Place this animal in a zoo and, though its stretching continues, its physique “goes to pot” and the cat becomes lazy. Why? Its aerobic exercise has ceased.
An individual’s capacity for sustaining heavy, prolonged muscular work is dependent upon the supply of necessary oxygen to the working muscles. The word ‘aerobic’ literally means “with oxygen.” Therefore, “aerobic work” is defined as work performed when sufficient oxygen can be supplied by the body to reduce the necessary performance of the task. According to Cooper, 1970, the most beneficial aerobic exercises include jogging, running, swimming, cycling, brisk walking, handball and basketball. The aerobic demand for these various forms of exercise is highly dependent upon the amount and rate of the work performed.
Aerobic exercise is a mandatory component in the overall Hygienic program of exercise. Some of these aerobic activities are far less demanding than jogging or swimming or some of the other exercises mentioned above. Low-intensity aerobic exercises, such as walking, must be of longer duration, but they are highly effective and are certainly regarded as aerobic activity. Choosing an aerobic type of exercise is dependent upon individual considerations such as age and level of physical fitness. Nearly anyone, regardless of physical condition, can effectively contribute to his/her own method of aerobic fitness.
Aerobic training activates many wonderful changes in the body. Your lungs will process more air with less effort, your heart will grow stronger and pump more blood with each beat, the number and size of the blood vessels carrying blood and nutrients to the body tissues will be increased, tone of the blood vessels and muscles will be improved and total blood volume will be increased.
The earliest to develop and most natural forms of exercise are walking and running. Primitive human beings survived by being able to walk or run great distances. We still have the bodily structure that was designed to cover 25 or more miles a day, but today our body rebels as soon as we attempt a 30-minute walk, let alone a 15-minute jog. We marvel at the stamina of the Tarahumara Indians of Mexico, who race at high altitudes in kickball games and relays that often last up to two days and cover one to two
hundred miles. Perhaps our fascination with their stamina is a subconscious recognition of our natural potentials. According to Dr. Thaddeus Kostrubala, M.D., for 3 million years the genus of homo sapiens had to run to survive. He also says that our femur thigh bone is designed specifically for running.
In order to zero-in on specific characteristics of aerobic activity, some advantages of a well-planned jogging or running program are briefly mentioned below. Running should be done for 30-45 minutes four or five times weekly. Keep in mind that the length of the work out must be gradually worked into and thus will vary with the individual. The advantages of integrating a running program to your life are rich and many.
A running program is a simple, effective way to stimulate the circulation and exercise the heart. It provides a gentle, steady and prolonged demand on the heart, more so than does a series of short, choppy, ballistic exercises. Running exercises many parts of the body simultaneously. It can be adapted to the age and physical fitness of the individual and can be performed at nearly any time or place. Another advantage of running is that it requires no special facility or equipment, therefore the costs are minimal. Running is a good therapy to reduce anxiety and depression.
A runner’s feet hit the ground 1600 to 1700 times during each mile. This can be rough treatment if done improperly. There are many criticisms of running as an exercise due to the high rate of injury. A recent Runner’s World poll reveals that 22% of runners suffer from knee injuries, 20% from achilles tendon injuries, 10% from shin splints and 9% from forefoot strain and fracture. It is a current consensus among experts who practice sports medicine and run or jog themselves that most of the injuries are due to overwork, faulty shoes, weakness, lack of flexibility and improper running techniques. According to Dr. George A Sheehan, M.D., running causes a loss of flexibility in the back of the legs. Because of this lack of flexibility, exercises that stretch the muscles in the entire legs and back are a necessary component in the exercise program. It is possible to increase your chances of avoiding injury by not running on a hard cement surface, selecting high-quality running shoes, performing stretching exercises to counteract the lack of flexibility caused by the contractile reactions of running and by improving the overall muscle strength of the major muscle groups involved.
Regardless of what form of aerobic exercise that you chose to adhere to, take the necessary cautions to prevent injury, be persistent with it, and the benefits of aerobic fitness will enhance your total well-being.
Aerobics is not a total physical fitness program. It must be integrated into a consistent exercise program which also includes stretching and contractile, strength building exercise. Though these three categories of exercise often overlap, all three (aerobics, stretching, contractions) are necessary for maximum health and joyful living.