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Periodization is a Flexible Strategy, Not a Rigid Tactic

I started studying Periodization in 1991 while in college and two years before my first job as a strength coach.

I remember being very excited about periodization because it gave me guidelines for designing programs for myself and the athletes I worked with at the time. All coaches that I interacted with used periodization in some form or another, and I never really questioned it. Thus, it was somewhat of a surprise to me that many coaches, personal trainers and even a few scientists are critical towards Periodization.

Especially due to my role as an author and lecturer, it has been important to me to understand the critique of periodization. I believe the critique of periodization is largely misdirected, and this article explains why.

This article begins with a review of the critique points of periodization. The following is a three-stage process for highlighting the role of periodization in training:

  1. Suggesting a 1st Principle of Physical Training
  2. Three characteristics of the process of developing physical qualities leads to the inevitable role of Periodization as a strategy
  3. The most effective periodization tactics

After reading this article you will understand the inevitable role of Periodization as a strategy and be excited about how much freedom you have to apply it through various tactics.

What are the critique points of periodization?

Suggesting a 1st Principle of Physical Training

A "principle" is a basic truth, law or assumption ( A first principle is a basic, foundational, self-evident proposition or assumption that cannot be deduced from any other proposition or assumption.

How could a 1st Principle of physical training be defined?

Athletes or fitness clients approach strength coaches and personal trainers to achieve a certain objective. Achieving this objective always requires a combination of:

Thus, the 1st Principle of Physical Training could be defined as using exercise to stimulate structural or functional adaptations specific to the athlete’s or fitness client’s goal.

What is required to stimulate structural or functional changes in the athlete or fitness client?

The process of stimulating functional or structural changes in the athlete or fitness client has three primary aspects that relate to the quality and quantity of the training stimulus:

  1. Physical abilities exist in a hierarchy.
  2. There can be positive and/or negative interactions between simultaneous training of different physical abilities.
  3. The body must be given a “reason” to adapt by stimulating a stress response.

Physical abilities exist in a hierarchy

The hierarchy exists because the development of certain abilities supports the subsequent training of ability, or, the training of a certain ability is more effective by first developing a more foundational ability.

Below is a list of 7 key relationships between physical abilities. A complete discussion of the physiology behind these relationships is beyond the scope of this article. Please see reference 15 at the end of this article for more information.

  1. Flexibility before strength
  2. Weak links before the entire kinetic chain
  3. Endurance of deep stabilizers before strength of prime movers
  4. Structural strength before functional strength
  5. Maximal strength before power or power endurance
  6. Technical/tactical ability through sports training, before using high intensity/high volume transmutation/conversion training
  7. Strength and conditioning before more demanding technical training

The hierarchy listed above implicitly includes the scope of rehabilitation to include proprioception, balance, tissue quality, muscle activation and pain management. This is just one reason why Periodization, as a strategy, also applies to the rehabilitation process.

Graph 1: The dynamic of development of two related abilities. Initially the more foundational ability has the primary focus. The other ability is in the program with a lower emphasis. Subsequently the emphasis shifts.

Note that the relationship between abilities results in different periods in the training program with different content of the training. For example, a period where flexibility is emphasized precedes a period where the development of strength is emphasized

There is opportunity for synergy and risk of incompatibility when abilities are trained concurrently

Concurrent Training occurs when endurance-based and resistance-based training are performed:

When two abilities are trained together, there is:

  1. Opportunity for synergy (for example, strength and power).
  2. Risk of incompatibility (for example, endurance and hypertrophy).

The interaction (synergy or incompatibility) can happen when a second component (B) is trained while there are still changes, adaptations or fatigue from component A occurring in the body.

---------------------------------- Timeline ------------------------------------------------------------------->
Component A
~~~~~~~~~~~~~~~~~~~~~ (component A adaptations/fatigue)
Component B
~~~~~~~~~~~~~~~~~~~ (Component B adaptations/fatigue)

Graph 2: Schematic representation of concurrent training.

Synergy is about abilities that should be in the same period – noticeably, strength and power.

Incompatibility is about elements that should be in different periods - incompatibility may be mostly about excessive fatigue rather than opposing molecular signaling.

In conclusion, knowledge about concurrent training effects supports the sequencing and organization of different physical abilities in different periods.

The body must be given a reason to adapt by stimulating the stress response

Classically, the body’s stress-response is believed to function based on homeostatic adaptations - any self-regulating processes by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival.

The homeostatic concept refers to stability, or a resistance to change. The homeodynamic model expands homeostasis and highlights that, together with stable conditions, potential for “jumps” in the physical states exist (bifurcation points). Interestingly, the underground book, Rock, Iron, Steel, mentions workouts that are so severe that the body will never forget it.

Homeostasis is the cornerstone of the General Adaptation Syndrome (GAS), which is the classic model for explaining how the body adapts to exercise. The GAS states that the body adapts to stress through:

Strength coaches and personal trainers recognize the above pattern from their work with athletes and clients. The rehabilitation process also requires optimal management of the stress-recovery response.

If the stress persists for an extended period of time, the body loses the ability to adapt to the stress and soreness, stiffness, staleness and maladaptation may occur. Thus, the GAS supports the use of alternating periods with an increased, developmental, and stressing training stimulus (training load) along with periods consisting of a reduced training stimulus that allows the body to recover and super compensate.

Graph 3: Possible development of performance throughout the alarm, resistance and exhaustion stage.

The Flexible Periodization Method sees the GAS as dealing mostly with the quantity of the training stimulus. In contrast, the Principle of Accommodation may be seen as a model that focuses on the quality of the training stimulus.

The Principle of Accommodation, often considered a general law in biology, states that the response of a biological object to a constant stimulus decreases over time. In the case of strength and conditioning or fitness training, the “biological object” is the human mind-body and the stimulus is the training load.

Graph 4: The Principle of Accommodation. The client may go through different experiences as performance gain tapers off with a given program.

Einstein is often attributed for stating, “the definition of insanity is doing the same thing over and over again and expecting different results.” When the athlete/client has adapted to a program and performance gains are low or non-existent, it is necessary to change one or more program variables in order to stimulate new progress. Thus, the Principle of Accommodation also points to the value of different periods with different contents in the training program.

The research that led to the GAS was done on rodents and GAS was seen as a generalized, predictable, purely physiological response revolving around the adrenals. This is in contrast to newer research which shows that stress responses are specific and individualized.

Thus, an allostatic (the process by which the body responds to stressors in order to regain homeostasis) model of adaptation has been proposed where the brain interprets the situation and anticipates the needs and initiates responses (adaptations) in order to maintain function. The perception of the situation is seen as critical.

The allostatic model does not strengthen the argument for different periods in the training. The allostatic model of adaptation highlights the possibility of affecting the dynamics of the stress-response through mind-body interactions:

The benefits are not only determined by the program, but also by what you believe about the program, your ability to execute it and to respond to it. Thus, optimally working with the mental aspects of training has the potential to shift the curves of the GAS and the Principle of Accommodation.

Graphs 5 & 6: The athlete’s or client’s optimal perceptions of the training program, the ability to execute it and to adapt to it has the potential to enhance training adaptations.

The above discussion leads to the realization that to stimulate structural and functional adaptations during training there are/is a need for:

A division into (different) periods is the essential definition of periodization.

What is the definition of periodization as the term relates to physical training?

There are various definitions of periodization in training research literature. However, they are not essentially different. (For an overview, please see reference 15.)

The definition that the Flexible Periodization Method operates with emphasizes the basic meaning of the word as well as a sequential aspect.

A strategy is the larger, overall plan designed to achieve a major or overall goal. The strategy can comprise several tactics. A strategy is broad, big picture and future oriented.

Thus, periodization is a strategy for organizing long-term training. The strategy is to divide the long-term cycle into different periods with different target training adaptations, structures and content of the training.

I have never encountered a critique of periodization as a strategy. All the critiques I have ever seen, including those in scientific literature, criticize specific periodization tactics.

For a strength coach or personal trainer to not use periodization, it would mean there were no identifiable periods in the training program and that the program was always the same. As this scenario is extremely unlikely, it is not so much about IF strength coaches and personal trainers are applying periodization; it is more about HOW strength coaches and personal trainers are applying periodization.

HOW periodization is applied falls into the realm of periodization tactics.

Periodization Tactics

Does periodization work? Which system is best? Those are the core questions addressed by previous and current day periodization research.

Tactics are plans, tasks, or procedures that can be carried out and may be part of a larger strategy. Because all studies, by necessity, involve specific applications of periodization, they speak mostly to periodization tactics.

Periodized versus non-periodized programs

As mentioned above, periodization is a strategy for organizing long-term training and may be more important the longer the training period is (beyond a few weeks).

However, even in short-term studies, periodized programs are as effective as or more effective than non-periodized programs for the development of strength or power. The benefit of periodization, when the end-goal is hypertrophy, is less researched.

Compared to the questions that face strength coaches and personal trainers, the bulk of periodization literature is limited to short-term (a few weeks to months) strength training of a beginner to intermediate athlete or fitness client. However, more and more research incorporate periodization concepts into the rehabilitation process.

Different periodization models

Research has focused on four major periodization tactics (often referred to as ‘models”) that are not necessarily mutually exclusive:

  1. Linear Periodization
    • A training plan that gradually increases intensity and decreases volume throughout multiple mesocycles
  2. Reverse Linear Periodization
    • A training plan where heavy weight for low reps progressively gives way to less weight and higher reps over several weeks or months
  3. (Daily) Undulating Periodization (DUP)
    • A training plan that manipulates multiple variables like exercises, volume, intensity, and training adaptation on a frequent basis
  4. Block Periodization
    • A training plan that focuses on breaking down specific training periods into 2-4-week periods. Each block encompasses three different stages: accumulation (50-75% intensity), transmutation (75-90% intensity), and realization (90%> intensity)

The classic conjugate system (a historical precursor to Block Periodization) has not been the subject of controlled research.

Note: In science, a model is a representation of an idea, an object or even a process or a system that is used to describe and explain phenomena that cannot be experienced directly. Thus, the models that have been researched are not periodization per se; they are descriptions of the phenomenon of periodization.

There are, in general, no (to negligible) differences between the results of different periodization models.

This result does not mean that it does not matter which periodization model strength coaches and personal trainers follow for a given client. Rather, it emphasizes that the optimal application of periodization changes from one scenario to another based on multiple factors. Because unaccustomed stress is a key to progress, it is possible that changing from one model to another could be a key to progress. The potential benefit of switching between periodization models is essentially an unstudied topic.

What are the elements that make periodization tactics effective?

The studies mentioned points to the following six periodization tactics to be effective. Additionally, some authors believe that training responses may be enhanced when the activity profile matches the pattern of human ancestors.

  1. Novelty, unaccustomed stress and frequent changes. For example, through variation in exercise volume and intensity.
  2. Higher workload.
  3. Higher intensity.
  4. Progressive overload should be performance based (auto regulated) with the option of also regressing.
  5. Choose a model that is the most motivating.
  6. Choose the model that results in strength gains at the right time (DUP, which results in earlier strength gains vs. Linear, which results in later strength gains)

The above points relate to three aspects which are key elements of periodization models.

  1. Parallel vs. sequential development of physical abilities
  2. Pattern of change in volume and intensity (linear, reverse linear, undulating)
  3. Application of variation and contrast (within weeks or between blocks)

These tactics are associated with certain training ages and competitive schedules.


The article listed key critique points of periodization. Subsequently, a 1st Principle of Physical Training was suggested. It was then argued how the process of stimulating physical changes is affected by three elements that result in different periods in a long-term training program – the essential definition of periodization.

  1. Physical abilities exist in a hierarchy.
  2. There can be positive and/or negative interactions between simultaneous training of different physical abilities.
  3. The body must be given a “reason” to adapt by stimulating a stress response

Last, periodization tactics were discussed, and effective elements pointed out.


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