In Essentials of Barbell Programming Part 1 and Part 2 I always make reference to the Theory of Stress and Supercompensation. Just to re-iterate, the theory of stress and supercompensation, (also known as the One Factor theory) is a four-step process. The first step is to apply a stress high enough to disrupt homeostasis. The body will initially react to this stress with fatigue and a drop off in performance. The second step is, with rest and proper nutrition, the body will recover from this stress and return to baseline homeostasis, which is the point where you started at when you applied the original stress. The third step is the supercompensation phase, also known as the “rebound effect”. That is where the body “gets stronger” physically, physiologically and technically. It is now above the baseline where you were before applying the stress. The fourth step is the loss of the supercompensation effect. In other words, if a new stress is not applied at the peak of supercompensation, your body will return to its baseline of homeostasis. Also known as the detraining phenomenon.  

Supercomensation Graph

In the One Factor theory, the immediate effect of a workout constitutes a depletion of certain biochemical substances, (as an example, glycogen after a strenuous anaerobic workout). After the restoration period, the level of the various substances is believed to increase above the initial level, and this is what is known as supercompensation.

If the rest intervals between successive bouts of training is too short, then all the substances will not have been restored and a decrease in performance will result.

If the rest intervals between successive bouts of training is too long, the supercompensation phase will be missed and no progress will be made.

Timing of training sessions is therefore critical in order to take advantage of supercompensation, with optimal rest intervals that will enable the body to recover and refill the biochemical substances, but not long enough to permit the organism to return to homeostasis.

The supercompensation model is by far the most popular training theory and the one that I most often use with my trainees. It’s straight forward, easy to understand and, provided all parameters are met, (nutrition, rest), it works.

There is another theory regarding the process of adaptation to the stress of training; it is called the TWO-FACTOR, or the FITNESS FATIGUE theory.

The Two-Factor theory of training is a rather more sophisticated and complex approach than the One Factor Theory.

In the Two Factor theory, the immediate effect of a training session is a combination of two processes:

a)    Increased fitness

b)    Fatigue

Therefore, after a training session an athlete’s preparedness increases due to fitness gains but also deteriorates due to fatigue. The final outcome is determined by the summation of the positive and negative changes. (see figure below):

The Fitness-Fatigue Model

The theory states that the fitness gains resulting from a training session is moderate in magnitude, but long lasting, whilst the fatigue effect is greater in magnitude, but short lasting. (Vladimir Zatsiorsky: Science and Practice of Strength Training, second edition).

It is assumed that for an average training load, the duration of the fitness gains and fatigue effect differ by a factor of three. In other words, the fitness gains will last three times longer than fatigue. As an example, if after a training session fatigue dissipates in 24 hours, the fitness gains will remain for 72 hours.

The two factor theory has now overtaken the Supercompensation theory as a more advanced programming protocol at the elite level and for certain training programs at the intermediate and advanced level of barbell training. It does take into consideration certain aspects that the Once-Factor theory doesn’t. For example, it is true that a training session depletes certain biochemical substrates, however in unequal amount and restoration is different among substances. A heavy training session will deplete glycogen levels, it will however have hardly any effect on another very important biochemical substrata, adenosine triphosphate (ATP), who’s value will not change substantially even after a heavy workout.

The restoration of initial levels of different substances requires different periods of time, thus to simply suggest a 48-hour period sufficient for restoration – as the One Factor Theory implies - is technically incorrect.

The question one may ask at this point is which theory is correct. The answer is both. Both the One Factor theory and the Two Factor theory are correct and have been used in many successful strength training programs. The Two Factor theory is simply an extension of the One Factor theory and should be used at intermediate and advanced levels of strength training, or even more so in the weeks proceeding a competition, where performance and thus full recovery before the performance is fundamental.  

Understanding the principles of the One Factor Theory and the Two Factor theory is fundamental when setting up a training program, and a Strength Coach must know how to use these two methods of training and when, and with who, to use them. For the most part I always prioritize the One Factor theory. It is a concept that has served me well for many years and has a proven record there where the objective is acquiring strength for everyday living. If performance is the objective then it will depend on how advanced the trainee is compared to his genetic potential. In this case the Two Factor theory can become extremely useful for progression in strength and technical skills.

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