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Periodization: Latest Studies and Practical Applications
By Christopher C. Frankel and Len Kravitz, Ph.D.

Periodization is an organized approach to training that involves progressive cycling of various aspects of a training program during a specific period of time. The roots of periodization come from Hans Selye’s model, known as the General Adaptation Syndrome, which has been used by the athletic community since the late 1950s (Fleck, 1999). Selye identified a source of biological stress referred to as eustress, which denotes beneficial muscular strength and growth, and a distress state, which is stress that can lead to tissue damage, disease, and death. Periodization is most widely used in resistance program design to avoid over-training and to systematically alternate high loads of training with decreased loading phases to improve components of muscular fitness (e.g. strength, strength-speed, and strength-endurance). This system of training is typically divided up into three types of cycles: microcycle, mesocycle, and macrocycle. The microcycle is generally up to 7 days. The mesocycle may be anywhere from 2 weeks to a few months and can further be classified into preparation, competition, peaking, and transition phases. The macrocycle refers to the overall training period, usually representing a year. This article will discuss the efficacy of periodization and present some of the current issues from recent research.

Theory and Research
The research has focused primarily on the variation in training volume (total repetitions per workout or total repetitions x mass lifted) and exercise intensity (%1RM). While the underlying mechanisms that explain the differences between periodized and non-periodized programs remains to be fully investigated and explained (Fleck 1999), the effects on neural adaptations and the avoidance of overtraining are suggested as possible factors (Fleck 1999, Stone 1999 a & b).

In these investigations, programs were evaluated based on changes in strength and/or power-related measures such as 1 RM bench, 1 RM squat,vertical jump power and height, and cycling sprint performance. The studies ranged in duration from seven to 24 weeks. When summarized, these studies demonstrate that even over a relatively short period of time (the length of a mesocycle), significantly greater improvements can be realized using systematic variation in training volume and intensity compared to linear programs using constant sets and reps (i.e., 3 sets of 10 repetitions).
In two separate studies, groups using a one-set-to-failure program were compared to other groups using periodized training principals.
Both methods resulted in improvements in strength and power measures over the training period. However, the periodized groups demonstrated significantly greater increases than did subjects in the single set groups (Fleck 1999). An obvious concern in the interpretation of these results is the greater amount of training volume (reps, sets, and total mass lifted) in the periodized programs, which may account for the differences in performance gains between the groups. However, these findings may furnish evidence for the use of periodized, multiple set, programs over single set programs, which continues to be an ongoing debate among fitness professionals.
To address the influence of overall training volume, multiple set linear programs (constant reps and sets) have been compared to periodized programs (decreased volume-increased intensity with time). In the majority of cases, periodization based programs still provided significantly greater improvements in performance measures (Fleck 1999, Stone 1999a, Stone 1999b). Therefore, there is evidence to support the idea that appropriate manipulation of volume and intensity, over and above just increases in total training volume alone, is an important factor in optimizing strength training effects.

Periodization, Variation, Periodization Models
Periodization, as it has been defined, refers to specific methods of manipulating training variables to provide variation in volume and intensity. While variation itself may play an important role in optimizing strength-related improvements, not all programs that include a variation component will provide similar results (Stone 1999a). In other words, random variations in training variables may not produce the desired results, lending credence to the adage "Fail to plan—plan to fail."

Traditional models of periodization describes a progression from high volume and low-intensity work towards decreasing volume and increasing intensity during the different cycles. Other periodization programs have been developed and have potential advantages over non-periodized approaches. A reduction in volume and an increase in intensity in steps during the training cycle is referred to as stepwise periodization. In the overreaching periodization model there is periodic short term (1-2 week) increase in volume or intensity followed by a return to normal training (Stone 1999b). During undulating periodization, training volume and intensity are increased and decreased on a regular basis, but not in the general pattern of always increasing intensity and decreasing volume as the training period progresses (Fleck 1999).

Practical Considerations
Coaches and athletes have long been aware of the benefit of changing the training stimulus at regular, or even irregular intervals. Tapering training volume prior to competition, planned periods of active rest, and
interspersing power and strength workouts to challenge different energy systems are all attempts to exploit the General Adaptation Syndrome. In the "black box" model of performance are qualitative variables such as motivation, adherence, and compliance which not be underestimated as determining factors in the success of any program. For instance, Stone et al. (1999b) describe that the attrition and noncompliance rate of their constant reps group was attributable to the monotony and boredom of this type of training. There may be psychological factors that additionally influence the quality and quantity of work performed during training.While the body of research pertaining to periodization focuses on the effect of varying volume and exercise intensity, it should be clear that these are not the only variables that determine training adaptations.

Other influential components of any program include
(1) choice of exercises
(2) order of exercises
(3) resistance or load
(4) number of sets per exercise
(5) number of exercises per muscle group
(6) repetition range
(7) type of contraction
(8) speed of movement
(9) rest periods between sets
(10) rest periods between training sessions, and
(11) nutritional status.
Further research remains to be conducted and evaluated. However, for more advanced resistance training designs, the evidence appears to strongly suggest utilizing a periodized approach as compared to constant repetition/set type programs.

: Volume (reps x sets) remains constant during training period. Intensity increases with load progression.

Random Variation: Volume and/or intensity change randomly, with no consideration other than to introduce variation into the program.


Step wise


Overreaching: Volume or intensity is increased for a short period of time (one to two weeks), followed by a return to "normal" training. This method is use primarily with advanced strength trained athletes.

Sample Periodization Model by Muscle Fiber Type

Articles Reviewed:

Stone, M. H., O’Bryant, H. S., Schilling, B. K., Johnson, R. L., Pierce, K.C., Haff, G. G., and Stone, M. (1999). Periodization: Effects of manipulating volume and intensity. Part 2. Strength and Conditioning Journal, 21(3), 54-60.

Stone, M. H., O’Bryant, H. S., Schilling, B. K., Johnson, R. L., Pierce, K.C., Haff, G. G., and Stone, M. (1999). Periodization: Effects of manipulating volume and intensity. Part 1. Strength and Conditioning Journal, 21(3), 54-60.