The words “work capacity” have joined the fashionable jargon of the industry. What exactly do they mean?

Some folks envision a sweaty multi-minute effort that makes the muscles burn and the heart pump, like a wrestling match or an 800m sprint. This is glycolysis.

Others lean towards manual labor, brief exertions interspersed with low-intensity activity going on for hours. In science talk this is “high power/low tempo” work. Alactic bursts with aerobic recovery. “A+A”, as Al Ciampa, SFG has snappily abbreviated it.

For some reason, predominantly aerobic exercise is rarely thought of when “work capacity” is mentioned.

A Real-World Explanation of Work Capacity

The tag “work capacity” goes back to post-war Sweden. In 1947, Swedish clinical physiologist T. Sjöstrand evaluated the “physical work capacity” (PWC) of ore smelting workers. He measured the amount of physical work they could do on a bicycle ergometer at a heart rate of 170 in a period of several minutes.

As all tests, this one is biased. A bicycle racer would leave a blue-collar worker in the dust. Then the latter would invite the former to hang with him for a shift at the steel mill. We have our own test, the SFG five-minute snatch test, that can be praised and criticized in the same manner.

The problem is, PWC is not only skill dependent — racing a bicycle or snatching a kettlebell — it is also energy system specific. When we talk about energy systems, “capacity” has a very straightforward meaning — the size of one’s fuel tank. And alactic, glycolytic, and aerobic “tanks” are all filled and emptied differently. You cannot test all three with one test. To complicate the matters further, all three systems work at the same time, albeit changing the ratios of their contribution to the total energy needs. So the “capacity” tested by the five-minute snatch test is not the same as the one tested by the ten-minute test.

The bicycle racer in our above example — a real racer, not a “mamil ”— has a huge aerobic tank that enables him to sustain a moderate effort for a long time. The steel mill worker, on the other hand, has high alactic capacity — plus efficient aerobic recovery. In other words, he manhandles heavy objects without going into glycolytic burn, then quickly recovers. It is the only way. If the worker stayed totally aerobic, he would not have had the strength to pick up the heavy metal. If he went “WOD” glycolytic, he would have collapsed into a worthless pile of sweat just minutes into the hours-long shift.

So when you utter the words “work capacity,” be ready to qualify the dominant energy system: alactic, glycolytic, or aerobic. Or, alternatively, specify the physical load parameters: power, tempo, and duration. If you do not, you are just spewing meaningless jargon.

How to Properly Train Your Energy Systems

There are proven training protocols for training all three energy systems. For the aerobic one refer to the book Peter Park recommends, The Big Book of Endurance Training and Racing by Dr. Phil Maffetone.

For glycolytic training stick to the guidelines outlined in the Long Rests blog: 20-50sec all-outbursts with super long rest periods and 1-5min 50% efforts. More about this in a near future.

An example of alactic training plus aerobic recovery is a Russian weightlifter’s or powerlifter’s training. He will do many sets of low reps far from failure, with adequate recovery and no pump or burn. “Work capacity” is not his goal, but a nice side effect of his system of strength training. Did you know that Olympic weightlifting champions Plyukfelder and Rigert would put in a full shift of work down in a mine before heading to the gym?

Maximov, Selouyanov & Tabakov (2011) explained:

“One can perform strength exercises not to failure. E.g., the athlete lifts a 16RM weight 4-8 times. In this case, local fatigue does not develop, there is no high acidification of muscles… A situation arises that stimulates the development of the mitochondrial network in glycolytic and intermediate muscle fibers. Therefore, a nearmaximal [70-90% intensity—P.T.] exercise with rest pauses develops the muscles aerobically.”

Gray Cook has pointed out that my ETK Rite of Passage military press plan is a work capacity protocol. Inspired by the Soviet weightlifting methodology, it has to be. Even though strength remains its number-one goal and alactic plus aerobic endurance is just a “WTHE.”

You Don’t Want Work Capacity — You Want General Endurance

You might ask, is there such a thing as “general work capacity” that covers all of the above? Yes, but it has a different name. The term accepted by Soviet sports scientists decades ago is “general endurance.”

In Russian sports science and coaching practice, every quality is subdivided into general and special. “General” refers to “…the ability… to perform any physical work more or less successfully.” (Ozolin, 2006) “Special” is the same thing as “sport-specific.”

“General endurance is the ability to perform for an extended period of time any work involving many muscle groups and placing high demands on the cardiovascular, respiratory, and central nervous systems.” (Ozolin, 2006)

The Takeaways on “Work Capacity”

When you have the urge to say “work capacity,” wait till it passes — or be ready to specify the dominant energy system or the power, tempo, and duration of the exercise.

If you are unwilling or unable to specify or have something broader in mind, say “general endurance.”

Next article, you will learn that the Russian meaning of the words “work capacity” is altogether different.

Visit the StrongFirst Research page to sign up for an upcoming protocol on these methods.