Work capacity is the most important factor in training that people know nothing about.
First, let me just start off with a working definition of work capacity and an explanation of why it’s so important. Work capacity is, essentially, the total amount of work you can perform, recover from, and adapt positively to.
The total volume of work you expose your body to essentially determines the magnitude of the training effect you receive from the work. We all intuitively know this. You don’t walk into the gym, warm up, do one easy set of 10 biceps curls, and expect to find yourself ripping the sleeves of T-shirts any time soon. You have to expose your muscles to more of a training stimulus.
How do you progress then to attain your 18-inch pythons of glory? (I’m already regretting the example I picked, but I’m too stubborn to go back. Curl bros, savor this moment.) Well, obviously, you do more work. You pick a more challenging weight, increase you sets, do more exercises, decrease your rest intervals, etc. It’s not rocket science, and we all know that eventually, if you want your arms to grow, you’ll have to do more work.
However, this concept seems foreign to most people when applied to anything besides arm hypertrophy. The fitness world has become so entranced by minimalism that we’ve forgotten that eventually, you just have to do more work. People are surprised when they do the same program with the same sets and reps and the same accessory work for several months, and they eventually plateau. Then they ask about it on a message board and get a response like, “Oh, you’re doing too much so you can’t recover. Dial back what you’re doing and you’ll keep getting stronger.”
So, lo and behold, they dial back their training volume and the gains start coming again. Only they last for a mere 4-8 weeks. Then they plateau even harder. Why? They weren’t getting stronger. They were peaking. Their body was accustomed to a certain level of work. When they reduced the amount of work, supercompensation happened, and they could put more weight on the bar. However, that’s not something that happens indefinitely. But, the fact is, it “worked” for a while, so this person ends up banging their head against a wall on a super low volume routine wondering why they’re not getting any stronger, not questioning the efficacy of their new routine because it worked initially.
Eventually, after months of wasted time, they decide to change things up. They start increasing their training volume, only to find that it beats them up, their lifts start regressing, and they start losing motivation to go to the gym. So clearly low volume was the way to go, they’ve just hit their genetic ceiling and are in for a lifetime of hard-fought, incremental gains. Then they weep and drown their sorrows in cheesecake.
Let’s dissect this little (perhaps all-too-familiar) vignette:
1) The guy originally plateaued because he wasn’t increasing the stimulus to his muscles and nervous system. Remember the SAID principle (specific adaptations to imposed demands)? The demands didn’t change significantly, and eventually the guy’s body had adapted all it intended to. Sure, as he initially got stronger, the slightly heavier weights were a slightly greater stimulus, but his body finally reached the point that training was no longer disrupting homeostasis enough to elicit a response.
2) He dials back the volume and gets stronger! It’s a miracle! Or, it’s what happens when your body is used to adapting to a certain level of stress, then you dial back the stress and you body is still used to the same magnitude of response. It would help to look at training in the (overly simplified, but still instructive) light of simply tearing a muscle down and building it back up. Let’s say your muscle mass is currently 100%, and your training breaks it down 20%, and since you’re plateauing, you build it back up 20% between sessions: 100 – 20 + 20 = 100. Then you dial back how much you’re tearing your muscles down, but your body is used to recovering 20% between sessions: 100 – 17 + 20 = 103 – 17 + 20 = 106. However, the fun doesn’t last forever. Your body catches on to the game, and your recovery again aligns itself with the training stress: 106 – 17 + 17 = 106. Voila, another plateau.
3) When he tries to add back in more volume, his body is used to recovering from less per session. However, he’s still trying to train at maximum intensity: 106 – 20 + 17 = 103. He perceives himself as getting weaker, gives up on the whole enterprise, and cries manly tears.