Biological Law of Accommodation

A graph that shows the rate of diminishing improvement in maximal strength as duration of exposure to unchanging stimulus increases.

The Biological Law of Accommodation

Vladimir M. Zatsiorsky is an authority on this subject as a biomechanist and author of a multitude of indispensable books and studies about the science of strength training. According to Zatsiorsky, the biological law of accommodation manifests in the way that “the response of a biological object to a given constant stimulus decreases over time. Thus, accommodation is the decrease in response of your body to a constant continued stimulus. In training, the stimulus is physical exercise”. In other words, keeping the stimulus the same will not result in the same results over time, due to something called homeostasis.


The human body dislikes change. This is one reason as to why addictions occur. When the body receives the same dosage of caffeine every day, it gets much better at metabolizing it and increases the amount of adenosine produced, as caffeine functions by taking its’ place. The former means that the individual requires a higher dosage to achieve the same effects as earlier. The latter means that restricting caffeine will result in tiredness and low levels of energy, as adenosine is partly responsible for the feeling of tiredness accumulating throughout the day. How does this translate to training?

If an individual were to exercise in the same manner over time, he would reach a point of diminishing returns, where the amount of energy invested is in a greater amount than the amount of benefits. If one were to do 3 sets of 12 repetitions on the close grip bench press every week, his progress in terms of hypertrophy and strength would stop progressing and thus stall, in a matter of a couple of weeks. The “couple of weeks” is mostly dependent on the strength level of the athlete. If a complete beginner, the couple of weeks changes to four or sometimes even more. If an elite, it changes to two weeks or (in many cases) less.

How to Avoid It

In order to avoid the biological law of accommodation, one must change the exercise parameters so that the stimulus received through exercise is not the same. There are multiple ways to do this, and they all have their advantages and disadvantages. Using all of these methods simultaneously is possible, but not required nor suggested, as it would cause difficulties with tracking progress. The methods fit into two main groups, which are the following: volume manipulation and exercise selection.

The volume manipulation category extends into four different methods:

  • Weight

Changing the weight and thus the percentage of the 1RM used. If an individual’s one-repetition maximum on the bench press is 100 kg, he could for example switch from doing 10 repetitions with 70 kg to 10 repetitions with 71 kg. These are close enough to both allow the individual to lift the weight while also increasing overall volume. Decreasing the weight by itself would not be helpful, as the overall volume would be lower.

  • Repetition Amount

The best match for altering the weight is altering the repetition amount. This would mean that one would either increase or decrease the amount of repetitions performed. If done on its’ own, the increase of repetition amount would for example be going from 20 repetitions to 21. Decreasing the amount of repetitions by itself would not be very helpful. Decreasing the amount of repetitions coupled with increasing the weight is a much better alternative. Going from 70 kg for 10 repetitions to 90 kg for three repetitions is an example of a time-tested manner of strength increase. Given that the volume with this alternative is lower, the optimal solution would be to change the set amount as well.

  • Set Amount

The amount of sets one performs per exercise. While doing three sets of 10 is commonplace, one can rarely see someone perform three sets of three repetitions on main movements. Instead, many do 8 sets of three, or even 10, in order to balance the total weekly volume and thus continue progressing. Altering the set amount in accordance to the weight and repetition amount is better than altering the set amount by itself. This is not to say that adding just one more set per workout is not a viable way to progress over time.

  • Frequency

How often a specific part of the body receives the stimulus, i.e. how often one exercises the same muscle groups or performs the same exercise. If one were to increase the amount of times they bench press in a week from two to three, their strength adaptations would most probably see an improvement. However, the frequency has its’ limits. It cannot be too high to disallow for adequate recovery. It cannot be too low as to not provide the muscle groups with sufficient stimulus for neuromuscular and strength adaptations. This range is dependent on the level of the athlete, once again. The complete beginner is usually able to get away with only one stimulus per week, while an elite may need to bench press thrice per week in order to increase his strength. Increasing frequency by itself is almost never a good idea as the weekly volume sees a massive, sudden increase leaving the body struggling to recover efficiently. When increasing the frequency, one must also alter the other volume manipulation parameters in order to increase the weekly volume by a slight and low amount instead.

The exercise selection category extends into three different methods:

  • Exercise Itself

This means that one would completely change the exercise performed. For example, the individual may switch from doing bench press as his main pressing movement, to dips. This method is usable as often as one likes but doing it often is not the best of ideas. Changing the exercise itself every week will result in a decrease of ability to track progress in terms of strength adaptations. This is due to the fact that exercises provide the individual with different leverages and joint angles, thus allowing different weights to be used. While the individual may be able to do 100 push-ups, he may not be able to bench press half of his bodyweight for the same amount of repetitions.

  • Exercise Variations

This means that one would only change a factor in the exercise performed and not the whole exercise itself. For example, the individual may now decide to perform the bench press with a close grip, or he may start deadlifting from blocks instead. In contrast to the whole exercises, variations are changeable as often as on a weekly basis (or even more often). Performing the bench press while going through pins heights, grip widths and paused repetitions will result in much better progress than performing the same variant all the time.

  • Equipment Usage

This means that one would only change the equipment used in the exercise, and not the complete variation or exercise itself. Some of the equipment could classify as their own variation when used. For example, changing out the deadlift with the banded deadlift. The same goes for any other kind of accommodating resistance equipment, including chains and slingshots. Using fat grips and other grip implements could also result in a completely different variation, depending on the core exercise. However, this is not all of the equipment. There are belts, wrist wraps, elbow wraps, straps and so on. Cycling the use of these is not required, and only elite and/or competitive lifters would benefit from doing so. For the powerlifter, the regular squat and the beltless squat are two completely different variations. For the recreational lifter, varying in belt usage may not be beneficial at all. Change equipment usage by itself or with exercise variations. Keep in mind that using some equipment could count as whole variations.


/Milos Askovic

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