Periodization Principles for Strength
by Tudor O. Bompa, PhD

Training guidelines fulfill a given training goal. Proper application ensures superior organization with the fewest errors. The principle of progressive increase of load in training leads to better adaptation and improved strength gains.

The Five Basic Laws of Strength Training
Any strength training program should apply the five basic laws of training to ensure adaptation, keeping athletes free of injury. This is especially important for young athletes.

Key Words
• Amortization Phase: The eccentric or yielding phase of an activity; also called the “shock-absorption phase.”
• Hormone: A discrete chemical substance secreted into the body by an endocrine gland that has a specific effect on the activities of other cells, tissues and organs.
• Innervate: To stimulate the transmission of nervous energy to a muscle.
• Testosterone: The male sex hormone; it produces masculinizing properties

Law Number One: Develop Joint Flexibility
Most strength training exercises use the entire range of motion of major joints, especially the knees, ankles, and hips. Good joint flexibility prevents strain and pain around the knees, elbows, and other joints. Ankle flexibility (plantar flexion, or bringing the toes toward the calf) should be a major concern for all athletes, especially beginners. Good flexibility prevents stress injuries. Athletes must start developing ankle flexibility during prepubescence and pubescence so that in the latter stages of athletic development it need only be maintained.

Law Number Two: Develop Tendon Strength
Muscle strength improves faster than tendon and ligament strength. Misuse and faulty utilization of the principle of specificity, or lack of a long-term vision, causes many training specialists and coaches to overlook overall strengthening of ligaments. Tendons and ligaments grow strong through anatomical adaptation. Without proper anatomical adaptation, vigorous strength training can injure the tendons and ligaments. Training tendons and ligaments causes them to enlarge in diameter, increasing their ability to withstand tension and tearing.

Law Number Three: Develop Core Strength
The arms and legs are only as strong as the trunk. A poorly developed trunk is a weak support for hard-working limbs. Strength training programs should first strengthen the core muscles before focusing on the arms and legs. The core muscles act as shock absorbers for jumps, rebounds, or plyometric exercises; stabilize the body; and represent a link, or transmitter, between the legs and arms. Weak core muscles fail in these essential roles, limiting the athlete’s ability to perform. Most of these muscles seem to be dominated by ST fibers because of their supporting role to the arms and legs. They contract constantly, but not necessarily dynamically, to create a solid base of support for the actions of other muscle groups of the body.
Many people complain of low back problems yet do little to correct them. The best protection against low back problems is well-developed back and abdominal muscles. Coaches and athletes must pay more attention to this area of the body.
Abdominal Muscles. The abdominal and back muscles surround the core area of the body with a tight and powerful support structure of muscle bundles running in different directions. Since many athletes have weak abdominal muscles in relation to their backs, general and specific abdominal muscle training is recommended. The rectus abdominis runs vertically and pulls the trunk forward when the legs are fixed, as in sit-ups, maintaining good posture. If the abdominal muscles are poorly developed, the hips tilt forward and lordosis or a swayback develops at the lumbar area of the spine because the low back muscles are much stronger.
The internal and external obliques help the rectus abdominis bend the trunk forward and perform all twisting, lateral bending, and trunk-rotating motions. They help an athlete recover from a fall in many sports and perform many actions in boxing, wrestling, and the martial arts. The anterior and lateral abdominal muscles perform delicate, precise trunk movements. These large muscles run vertically, diagonally, and horizontally.
Isolating the abdominal muscles requires an exercise that bends the spine but not the hips. Exercises that flex the hips are performed by the iliopsoas (a powerful hip flexor) and to a lesser extent by the abdominals. Sit-ups are the most popular abdominal exercise. The best sit-up position is lying on the back with the calves resting on a chair or bench. This position isolates the abdominals since the hips are already bent.
Back Muscles. The back muscles, including the deep back muscles of the vertebral column, are responsible for many movements such as back extension and extending and rotating the trunk. The trunk acts as the transmitter and supporter of most arm and leg actions. The vertebral column also plays an essential role as a shock absorber for landing and takeoff actions.
Excessive, uneven stress on the spine or sudden movement while in an unfavorable position may lead to back problems. For athletes, back complaints may be due to wear and tear caused by improper positioning or forward tilting of the body. Disc pressure varies according to body position relative to external stress. Stress on the spine increases during lifting in standing or seated positions or when the upper body swings, such as in upright rowing or elbow flexion. Sitting produces greater disc pressure than standing; the least stress occurs when the body is prone (such as in bench presses or pulls). In many exercises that use the back muscles, abdominal muscles contract isometrically, stabilizing the body.
The Iliopsoas. The iliopsoas is an essential muscle for hip flexion and running. Though not large, it is the most powerful hip flexor, responsible for swinging the legs forward during running and jumping. Sports performed on the ground require a well-developed iliopsoas. Exercises such as leg and knee lifts against resistance are key to training this important muscle.

Law Number Four: Develop the Stabilizers
Prime movers work more efficiently with strong stabilizer or fixator muscles. Stabilizers contract, primarily isometrically, to immobilize a limb so that another part of the body can act. For example, the shoulders are immobilized during elbow flexion, and the abdominals serve as fixators when the arms throw a ball. In rowing, when the trunk muscles act as stabilizers, the trunk transmits leg power to the arms, which then drive the blade through the water. A weak stabilizer inhibits the contracting capacity of the prime movers.
Improperly developed stabilizers may hamper the activity of major muscles. When under chronic stress, the stabilizers spasm, restraining the prime movers and lessening athletic effectiveness. At the shoulders, supra- and infraspinatus muscles rotate the arm. The simplest, most effective exercise to strengthen these two muscles is to rotate the arm with a partner tightly holding the fist. The resistance provided by the partner stimulates the two muscles stabilizing the shoulder. At the hips, the piriformis muscle performs outward rotation. To strengthen this muscle, the athlete should stand with knees locked. While a partner provides resistance by holding one foot in place with both hands, the athlete performs inward-outward leg rotations. At the knees, the popliteus muscle rotates the calf. A simple exercise is for the athlete to sit on a table or desk with the knees flexed. A partner provides resistance by holding the foot as the athlete performs inward-outward rotations of the calf.
Stabilizers also contract isometrically, immobilizing one part of the limb and allowing the other to move. Stabilizers can also monitor the state of the long bones’ interactions in joints and sense potential injury resulting from improper technique, inappropriate strength, or spasms produced by poor stress management. If one of these three conditions occurs, the stabilizers restrain the activity of the prime movers, avoiding strain and injuries.
Unfortunately, few coaches take the time to strengthen the stabilizers. Time should be set aside during the transition and preparatory periods, especially the anatomical adaptation phase for stabilizer training. The core muscles, rotators, and stabilizers should be developed using long-term progression (figure 3.1). A casual approach would be a disservice to the serious athlete.

Law Number Five: Train Movements, Not Individual Muscles
Athletes should resist training muscles in isolation as in bodybuilding. The purpose of strength training in sports is to simulate sport skills. Athletic skills are multijoint movements occurring in a certain order, called a kinetic chain (movement chain). For instance, a takeoff to catch a ball has the following kinetic chain: hip extensions, then knee extensions, and finally ankle extensions, in which the feet apply force against the ground to lift the body.
According to the principle of specificity, body position and limb angles should resemble those for the specific skills. When athletes train a movement, the muscles are integrated and strengthened to perform the action with more power. Therefore, athletes should not resort to weight training alone, but should broaden their training routines, incorporating medicine balls, rubber cords, shots, and plyometric equipment. Exercises performed with these instruments allow athletes to initiate skills more easily.

Principle of Progressive Increase of Load in Training
According to Greek mythology, the first person to apply the principle of progressive increase of load was Milo of Croton. To become the world’s strongest man, Milo started to lift and carry a calf every day. As the calf grew heavier, Milo grew stronger. By the time the calf was a full-grown bull, Milo was the world’s strongest man thanks to long-term progression.
Improved performance is a direct result of quality training. From the initiation stage to the elite performance stage, workload in training must increase gradually according to each athlete’s physiological and psychological abilities. Physiologically, training gradually increases the body’s functional efficiency, increasing its work capacity. Any dramatic increase in performance requires a long period of training and adaptation (Astrand & Rodahl, 1985). The body reacts physiologically and psychologically to the increased training load. Similarly, nervous reaction and functions, neuromuscular coordination, and psychological capacity to cope with stress also occur gradually. The entire process requires time and competent technical leadership.
Several sports have a consistent training load throughout the year, called a standard load. Most team sports maintain 6 to12 hours of training per week for the entire year. Standard loading results in early improvements, followed by a plateau and then detraining during the competitive phase (figure 3.2). This may cause decreased performance during the late competitive phase, since the physiological basis of performance has decreased and prevent annual improvements. Only steady training load increments will produce superior adaptation and performance.
The overload principle is another traditional strength training approach. Early proponents of this principle claimed strength and hypertrophy will increase only if muscles work at their maximum strength capacity against workloads greater than those normally encountered (Lange, 1919; Hellebrand & Houtz, 1956). Contemporary advocates suggest that the load in strength training should be increased throughout the program (Fox et al., 1989). As such, the curve of load increment constantly rises (figure 3.3).