Responses to Training Stress
The manner in which the human body reacts to stress was described by Canadian biologist and endocrinologist Hans Selye as the General Adaptation Syndrome (GAS) (19). Selye delineated a three-stage response to stress (alarm, resistance, and exhaustion). Later, Garhammer applied Selye’s GAS concept to resistance training and exercise conditioning (10). When the body experiences a new stress or a more intense stress than previously applied (e.g., lifting heavier resistance training loads or a greater load-volume; see chapter 15), the first response is the shock or alarm phase.
This phase may last several days or several weeks, during which the athlete may experience excessive soreness, stiffness, and a temporary drop in performance. Next is the resistance phase, one in which the body adapts to the stimulus and returns to more normal functioning. In this phase, the body is able to demonstrate its ability to withstand the stress, an attribute that may manifest itself for an extended period depending on the health and training status of the athlete. Here, the athlete relies on neurological adaptations to continue training while the muscle tissue adapts by making various biochemical, structural, and mechanical adjustments that lead to increased performance (22). This phase of adaptation is sometimes called supercompensation.
However, if the stress persists for an extended time, the exhaustion phase is reached. Some of the same symptoms experienced during the alarm phase reappear (fatigue, soreness, etc.), and the athlete loses the ability to adapt to the stressor. Staleness, overtraining, and other maladaptations may occur when there is no training variety or when the training stress is too great. In addition, non-training-related stress (e.g., occupational issues, insufficient sleep, poor diet) can contribute to the overall stress level and lead to the exhaustion phase. It is this phase that the strength and conditioning professional should strive to avoid. Although the actual dimensions (i.e., slope, magnitude, and timing) of the curve shown in Figure 1 vary based on the individual athlete, the figure illustrates the three distinct phases of the body’s response to training stress.
Figure 1
Periodization Cycles
The traditional periodization model partitions the overall program into specific time periods. The largest division is a macrocycle, which typically constitutes an entire training year but may also be a period of many months up to four years (for Olympic athletes). Within the macrocycle are two or more mesocycles, each lasting several weeks to several months. The number depends on the goals of the athlete and, if applicable, the number of sport competitions contained within the period. Each mesocycle is divided into two or more microcycles that are typically one week long but could last for up to four weeks, depending on the program (4,5,6,8,9,20,22). This short cycle focuses on daily and weekly training variations.
Periodization Periods
The planned implementation of the meso- and microcycles within an overall macrocycle is the basis for changing (varying) the program design variables. Predominantly, it is the intensity and volume assignments of the training and conditioning programs that are manipulated to the greatest extent. Sport-specific training also involves acquiring and perfecting skill-related techniques, but attention (time) dedicated to these outcomes varies based on their relative importance to the match or game schedule. Therefore, periodization involves shifting training priorities from non-sport-specific activities of high volume and low intensity to sport-specific activities of low volume and high intensity over a period of many weeks to prevent overtraining and optimize performance.
The periodization model and the process of moving through the periodization cycles or phases can also be likened to the sequence and evolution of learning academic concepts and skills from simple to complex (see chapter 17 for a detailed explanation and application).
According to Matveyev, the major divisions of training are the preparatory, competition, and transition periods (15). Later, Stone, O’Bryant, and Garhammer added a “first transition” between the preparatory and competitive periods (21). Thus, the conventional periodization model includes four distinct periods: preparatory, first transition, competition, and second transition. Figure 2 illustrates the periodization model that can be applied to athletes with a novice or lower training status. Intensity begins lower and gradually increases, and volume starts higher and slowly decreases as the athlete becomes conditioned. Not all novice athletes, however, are able to tolerate large changes in these variables (15,22,24). Also, because advanced athletes invariably train closer to their abilities and have smaller adaptational windows, their volume and intensity assignments are consistently higher, as seen in Figure 3 (7,11,20,22). This modification of Matveyev’s model reveals a shift from lower intensities and higher volumes earlier in the preparation period to higher intensities and lower volumes in the competition period, but the fluctuations are smaller and occur in the upper end of their values.
Figure 2
Figure 3
Preparatory Period
The initial preparatory period is usually the longest and occurs during the time of the year when there are no competitions and only a limited number of sport-specific skill practices or game strategy sessions. The major emphasis of this period is establishing a base level of conditioning to increase the athlete’s tolerance for more intense training. Conditioning activities begin at relatively low intensities and high volumes: long, slow distance running or swimming; low-intensity plyometrics; and high-repetition resistance training with light to moderate resistances. Because high-volume training causes significant fatigue and can involve large time commitments, the athlete is not exposed to optimal conditions (i.e., does not have enough time or energy) for improving sport-specific technique. As a result, technique training is not a high priority during this period (4,5,6). As the preparatory period unfolds, however, microcycles are designed to gradually increase resistance training loads and sport conditioning intensity, decrease training volume, and give more attention to sport technique training.
A further modification of Matveyev’s original model was the creation of three phases within the preparatory period that delineate more refined differences in training intensity and volume, especially for the resistance training component. In order, these are the hypertrophy/endurance phase, the basic strength phase, and the strength/power phase (20,22).
Hypertrophy/Endurance Phase
The hypertrophy/endurance phase occurs during the early stages of the preparatory period and may last from one to six weeks (8). During this phase, training begins at a very low intensity with very high volume. The goals for this phase are to increase lean body mass or develop an endurance (muscular and metabolic) base, or both, for more intense training in later phases and periods (4,5,6). Initially, the sport conditioning activities may not be specific to the athletic event. However, as the preparatory period continues over several weeks, the training activities become more specific to the sport. For example, a sprinter may begin the preparatory period with longer-distance runs (longer than his or her competition distance) at slower speeds, lower-intensity plyometrics such as double-leg bounding and hopping, and resistance training exercises that are not necessarily biomechanically or structurally similar to running (hip sled, leg curl, etc.). The athlete may also handle very low to moderate loads for many repetitions in a resistance training program (Table 1). This phase may be followed by an intermediate recovery week or microcycle of low-intensity, low-volume training prior to the beginning of the next phase.
Table 1
Essentials of Strength Training and Conditioning, Third Edition, published by Human Kinetics, is the most-preferred preparation text for the Certified Strength and Conditioning Specialist® (CSCS®) exam. It explores the scientific principles, concepts, and theories of strength training and conditioning as well as their applications to athletic performance. The book is available in bookstores everywhere, as well as online at the NSCA Store.
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