Strength is measured by the amount of force you can produce with a single maximal effort. You need strength to increase work capacity; to decrease the chance of injury; to prevent lower back pain, poor posture and other hyperkinetic diseases; to improve athletic performance; and perhaps save life or property in an emergency. Strength training increases strength of bones, tendons and ligaments, as well as muscles. It has been found to be therapeutic for patients with chronic pain.
Power training increases strength and endurance up to a point but is primarily useful in preparing you to perform activities that require power. Examples of activities requiring power are throwing, striking and jumping skills in sports and dance or throwing heavy loads in farming and industry.
So what are the BASIC Facts about Strength? There are three types of muscle tissue; they are-smooth, cardiac and skeletal. Each has a different structure and function. Smooth muscle tissue consists of long, spindle-shaped fibers; each fiber usually contains only one nucleus. The fibers are involuntary and are located in the walls of the esophagus, stomach and intestines, where they function to move food and waste products through the digestive tract. Cardiac muscle tissue is also involuntary and, as its name implies, it is found only in the heart. Skeletal muscle tissues consist of long cylindrical, multinucleated fibers. They provide the force needed to move the skeletal system and may be slow, intermediate and fast twitch fibers.
Some experts suggest that strength training using high resistance exercises tends to selectively develop fast-twitch muscle fibers. Fast-twitch fibers generate greater tension than slow-twitch fibers, but they fatigue more quickly. They primarily use anaerobic metabolism. These fibers are particularly suited to fast, high-force activities such as explosive weight lifting movements, sprinting and jumping. Strength training primarily increases the size of fast-twitch fibers though intermediate fibers also increase in size and take on fast-twitch fiber characteristics with training.
An example of fast-twitch muscle fiber in animals is the white meat in the flying muscles of a chicken. The chicken is heavy and must exert a powerful force to fly a few feet up to a perch. A wild duck that flies for hundreds of miles has dark meat (slow-twitch fibers) in the flying muscles for better endurance.
The amount of force you can exert during a strength test depends upon the speed of contraction, muscle length, warm-up, and other muscle-related factors. If you want to score high on a strength test, consider some of the secrets of success used by experienced lifters and proven research. Generally, a muscle exerts the least force as it becomes shorter (toward the end of a movement), and can exert more force during an isometric contraction than when it is shortening. The muscle exerts the most force when it is lengthening (lowering a weight). If a muscle is placed on a slight stretch immediately before it contracts, it can exert more force than it could if it started from a resting length.
Speed of contraction affects the amount of force that can be exerted. A slow contraction can lift a heavier weight than a fast contraction and it is safer. If muscles are warmed up before lifting, more force can be exerted and heavier loads can be lifted.
It is important to note that strength capacity differs with gender and age. Women have less muscle mass than men and typically average 60 to 85 percent of the absolute strength of men. However, women are as strong as men, in relative strength. Maximum strength is usually reached in the twenties and declines with age. Regardless of age or gender, strength can be improved.
Applying the “overload principle”, so that exercise is done with a near maximum resistance with only a few repetitions best develops strength. In order to increase strength, the muscle must be contracted to at least 60 percent of its maximum. Strength training requires an overload in the amount of the resistance, while muscular endurance requires an overload in the number of repetitions. Therefore, according to the law of specificity, when designing a program for strength development, high resistance and low repetitions at a moderately slow speed should be used for maximum effectiveness.
When you begin strength training, there will be marked improvements during the first couple of weeks. This is primarily due to motor learning factors rather than to muscle growth. Thereafter, improvements will be slow and the changes will be the result of hypertrophy of the muscle.
There is a threshold of training and a target zone for muscular strength development. Experts generally agree that in “progressive resistance exercise (PRE) using maximum load (resistance) for three to eight repetitions in one to three sets or four times a week will develop strength. Experts do not agree, however, on the ideal combination of repetitions, sets and speed. At least one study suggests that doing just one set will initially build as much strength as three sets. Over time those who do three sets will probably continue to gain strength for a longer period than occurs with only one set.
The amount of exercise necessary to maintain strength is less than the amount needed to develop it. Recent evidence suggests that once strength is developed it may be maintained by performing fewer sets or performing exercises fewer days per week. For example, if you have performed three sets three days per week you may be able to maintain current levels of strength with two sets or by exercising two rather than three days per week. If schedules of fewer sets or fewer days per week result in strength loss, schedules must be returned to original amounts.
A word of caution, if the target zone is exceeded an “overload syndrome” may result. If the frequency, intensity or time of your training program exceeds the optimum and you try to progress too fast, inflammatory changes in the muscles, tendons or joints may occur. The ability of muscles to contract may decrease or loss of lean tissue may occur, so improvement stops and strength is actually lost.
If you are an athlete, periodization of training may help prevent “overtraining” or the “overload syndrome”. When an athlete trains for a single performance or perhaps several competitive events such as games or matches during a sport session, it requires careful planning to reach peak performance at the right time and to avoid overtraining and injuries. Periodization is a modern concept of manipulating repetition, resistance and exercise selection so there are “peaks” and “valleys” (tapering-off) that are associated with the sports schedule. Training normally begins with high repetitions and low resistance. The resistance is gradually increased and the repetitions are decreased as each climax approaches.
A strength-training program should apply the “principle of specificity” by closely resembling the activity for which the strength is needed. Specificity of training will enhance performance. If you want your arms to be stronger so you can “carry” heavy loads, or if you want finger strength to “grip” a heavy bowling ball, much of your strength exercise should be done isometrically, using the arm muscles the way you use them to carry loads or using fingers the same way you hold the bowling ball. On the other hand, if the task for which you are training is performed “isotonically”, your strength program should be primarily isotonic use of the muscles involved in that skill.
If you are training for a particular skill that requires “explosive power”, such as throwing, striking or kicking, or jumping, your strength exercises should be done with less resistance and greater speed. If you are training for a skill that uses both concentric and eccentric contractions or is plyometric, you should perform strength exercises using these characteristics.
Training for cardiovascular endurance at the same time as strength training may prevent maximum results in both. Studies have shown that simultaneously training for strength and cardiovascular endurance may not produce the same result as one could obtain while training for either one separately. Some people have interpreted this to mean that they interfere with each other. The cause of this is not clear. It may be that the time spent on each one is less or that overtraining occurs rather than the fact that one inhibits the other. Whatever the cause, the differences are relatively minor and it should not prevent an individual from doing both concurrently.
Strength developed in one limb can be transferred to another unexercised limb. When the right arm is trained its strength increases, the unexercised left arm will also increase in strength, though not as much as the exercised arm. This phenomenon is called “transfer of training”, “bilateral transfer” or “cross-education”. The reason for this is not fully understood, but the phenomenon is sometimes applied in rehabilitation to prevent injured muscles from atrophying.
Progressive resistance exercise (PRE) is the most effective type of strength training program. Muscles adapt only to the load placed upon them; therefore, in order to continue increasing strength, you must progressively increase the stress on the muscle as it adapts to each new load. Muscle groups differ in their strength potential, so each muscle group must have an individualized program (target zone). For example, the legs and trunk can usually lift greater loads than the arms.
The “double progressive system” is an effective variation of the PRE system. The double progressive system of progression periodically adjusts both the resistance and the number of repetitions. For example, you may begin with three repetitions for the arms. Once a week, you add one repetition. When you gave progressed to eight repetitions, increase the weight by five pounds. Decrease the repetitions to three and begin the program again.
In my next article I will be discussing the facts about the different types of resistance training. It is important to note that strength training is a progressive program of various types of resistance methods. Depending on your goals it is necessary to know what method will give you the best results. Start training now and become stronger, faster and fitter!