What is “Work Capacity”? [Part II]

The original Russian term rabotosposobnost literally translates into “work ability.” A better translation would be “potential productivity.”

But someone creatively translated it into English as “work capacity,” which instantly changed its meaning. The word “capacity” implies the size of a tank, as in “alactic capacity” or “aerobic capacity.” The Russian term, while including capacity, means a lot more.

Work CapacityThe Definition of Potential Productivity

Even in the USSR there was vagueness and many conflicting definitions of potential productivity (PP). I will spare you the esoteric discussions and present you with a definition that many Russian experts would agree with — or at least could live with:

“Potential productivity is one’s ability to fulfill the given work with the lowest biological cost and the highest results.” (1)

“Potential productivity is a complex process which depends on integration and interaction of different systems and organs on different levels of organization: from biochemical to genetic to social.” (2) PP is determined by a host of physiological and psychological factors: genetics, gender, body mass, age, the state of health, energy systems’ power, capacity, and efficiency, the state of the neuromuscular apparatus, the psychological state, motivation, the climate, the season, work conditions, etc.” (2)

As you can see, the energy systems are only one of the many variables determining the PP.

PP should be assessed according to the criteria of one’s job or sport.(3) Indirect criteria of PP include various biological markers such as the heart rate and the blood pressure that describe the organism’s reaction to the load and the cost it incurred doing the work.(3)

The Three Phases of Potential Productivity

PP has three phases: rising productivity, stable high productivity, and rising fatigue. The first phase can be thought of as a warm-up. Depending on the individual and the nature of the effort, it may last from several minutes to ninety minutes. You are “cruising” in the second phase. As for the third phase, fatigue is the organism’s defense reaction that aims to lower various systems’ output to prevent negative consequences to one’s health.

If you look at the productivity dynamics during the workday, you will see that after lunch the first phase is shorter than in the morning — but the second phase does not reach as high and does not last as long. The third phase is predictably more pronounced in the end of the day. This applies to both physical and mental work.

Potential Productivity Dynamics During the Work HoursBiorhythms affect the PP and should be considered in planning.(4) The highest productivity is exhibited when one’s work or training rhythm is in sync with his biological rhythms. 41% of people are most productive in the morning, 30% in the evening and even at night, and 29% are equally productive at any time when they are awake.(5) If you want to learn more, Dr. Craig Marker, SFG II recommends an interesting paper in English.(13)

Potential Productivity TypesHere are most typical PP dynamics over a 24-hour period:
Strength is down by 20-30% after sleep and it takes three to five hours to reach its peak. It decreases again by 1300.(6) A first peak is around 0900 (based on 0600 waking up), the second peak is reached around 1800.(7)

Potential Productivity Over 24 HoursYet, you can retrain yourself to have high potential productivity at unfavorable times:(8)

“Maximal potential productivity is a dynamic stereotype and dynamic stereotypes can change if you make them. That means that if the most convenient time for your training falls outside [the optimal times of the day], the organism will gradually, say over a month, will move its potential productivity peak to that time. The most important thing is not to change that time too often, otherwise the dynamic stereotype will not be reinforced and you will be constantly feeling discomfort.” (9)

Work Capacity Peaks on Wednesday

Many cyclical phenomena are fractal, i.e. they repeat themselves at periods of time of different length, like Russian nesting dolls. When it comes to a weekly cycle, Soviet weightlifting experts figured out decades ago that the peak of work capacity falls not on Monday but on Wednesday.(10)

Potential Productivity PeaksRussians also distinguish between monthly, annual, and multiannual potential productivity. PP peaks in the end of summer-early fall and bottoms out in the winter.(11) Note the climate’s influence: in moderate — by Russian standards — climates the winter drop-off is 4-8%, in Siberia it is 17%. Soviet researchers established that a several weeks’ long vacation is a must once a year as nights and weekends off do not erase the cumulative fatigue from months of work. What you might see as European laziness is in fact a prerequisite for maximizing your work capacity throughout the year.

How to Improve Your Potential Productivity

Since PP is a lot more than the energy systems, you can and should do a lot more to improve yours. Russians undertake various measures for maintaining, increasing, and restoring PP:(3)

  • Pedagogical means encompass an intelligently designed training and recovery process: selecting the right loads and their variability, optimizing the work/rest schedule, intelligently combining general and specific training means, etc.
  • Psychological means include autogenic training, muscle relaxation and breathing exercises, increasing positive emotions and decreasing negative emotions in one’s life, organizing recreation, etc.
  • Medical means include pharmacy, physiotherapy, massage, etc.
  • The physiological category is further subdivided into two groups:
    1. The first group of means is meant to be used in an ongoing manner over the length of one’s professional or athletic career: balanced nutrition, nutritional supplementation, measures aimed at increase of the body’s non-specific resistance, GPP, sauna, etc. A key to developing stable PP is improving of the body’s non-specific resistance to stressors: various adaptations in the metabolism, immune system, endocrine system, especially the sympathetico-adrenal system and adrenal cortex, etc.(2)
    2. The second category is short term, for a quick pick-me-up before or during a competition and extra restoration immediately after. These means includes acupuncture and acupressure, hypobaric and hypoxic training, pharmacy, etc. E.g., cold shower and application of a cold compress to the stomach between sets improves results in weightlifting, especially for trained athletes. Rubbing one’s face with cold water during competition also helps because cold is a stressor that activates the cortico-adrenal system.(12) Of course, there is espresso and Iron Maiden.

In summary, to maximize your potential productivity you need to, in addition to training right, do whatever it takes to become happy and healthy.

  • Train right.
  • Rest enough.
  • Eat well. Supplement right — or not at all.
  • Get your head in the right place.
  • Take up autogenic training or meditation.
  • Study your body’s natural rhythms and live and train in sync with them.
  • Engage in natural health practices: outdoor activities, tempering, sauna, massage, etc.
  • Learn moderation.


  1. Shipilina & Samokhin (2004)
  2. Ushakov (2007)
  3. Solodkov et al. (2007)
  4. Agajanyan & Shabatura (1989)
  5. Doskin & Lavrentyeva
  6. Vasiliev (1953)
  7. Cited by Hettinger (1966)
  8. Smirnov (1955)
  9. Sheyko (2005)
  10. Rodionov (1967)
  11. Zagryadsky (1972)
  12. Vorobyev (1981)
  13. Kudielka et. al (2006)

Get higher results for a lower biological cost.

Pavel Tsatsouline
Pavel Tsatsouline is the CEO of StrongFirst, Inc.

13 thoughts on “What is “Work Capacity”? [Part II]

  • I´d be curious to hear some thoughts and experiences on the WTH effect when it comes to “work capacity” in general. I´ve noticed it myself that (heavy) swings carry over to many athletic endeavours form walking, sprinting to martial arts. It´s interesting how one training modality can have such a big impact on many different fields – thus the name, WTH effect I guess?

  • That was a very informative post thank you very much. I do have one question. The need for several week vaction to help recover, is that a complete separation from iron or just a dramatic reduction or subjective based on how hard you currently train?

  • The graph labeled “Here are most typical PP dynamics over a 24-hour period:” provides an interesting discussion point. I’m curious what population was used to gather this cycle given the PP peak that occurs around 19 00, followed by a very sharp decline over the next three hours before sleep. Has this been observed in numerous populations or just the one used at the time of the Russian study?

  • The graph that shows the peaks and valleys over the 24 hour period via military time is confusing me a little. Midnight is 24 or 0 in military time so does the 12 at the far left mean this graph starts tracking at 12 noon and midnight is in the middle of the graph?


  • While I thoroughly enjoy the posts that specifically address training, it is refreshing to see a blog post that explores the integration of training into a whole life.

    There is room to explore more deeply how the cyclical nature of a day telescopes out into a week, a month, and a year of training. Charlie Francis’ “Supercompensation and Recovery” text, Siff’s latest Supertraining, and Zatsiorsky’s Science of Strength Training do a fair job of hinting at this, but none of those authors explore it deeply and connect/relate the structure of a daily cycle to the annual cycle (as an example).

  • My previous trainer (not SF but top notch nonetheless) advised that every athlete needed to pay attention to the five corners of his life …


    * Eat real food and drink water.
    * Sleep great for 7-8 … rest & recovery is the flip side of hard training.
    * Move a little a lot (every day throughout the day be active, take stairs, walk etc …) & Move a lot a little (train hard & smart, preferably with a capable SF instructor).
    * WE is our social life. This is the source of most of our Happy/Unhappy and the people you spend time with are the person you become … pick wisely.
    * ME … are you doing something that matters to you … are you cultivating a strong Mindset … purpose & meaning matter.

    He also believed that our fitness practice was the Keystone Practice that helped us perform better in the other arenas of our life … a fit person tends to eat better, sleep better, move better, take personal responsibility and for some strange reason is often easier to get along with … most of the time (or maybe we just instinctively know it’s best to talk nice to strong fit athletes).

    Great post chairman.


    • Dan John wrote about a similar balance that he had learned in Catholic school. I forget which book covers it. Eat – Sleep – Play – Pray. And the four pillars should both interact and spiral outward as you add things to your life.

  • I like that term “potential productivity.” Much more comprehensive way of looking at things. The time and things done in the gym are just a fraction of training.

This article is now closed for comments, but please visit our forum, where you may start a thread for your comments and questions or participate in an existing one.

Thank you.