The 40% Rule, as David Goggins calls it in his book Can’t Hurt Me, is the idea that whenever you feel like you’re tank is about empty in whatever area, you’ve only used about 40% of your capacity. I’m not sure how he arrived at the math, but I know there’s some truth there.
I would say that it’s accurate that most of us give up too soon. That’s why fitness franchises that use instructor-led or ‘WOD’ (workout of the day) models like Orange Theory or CrossFit are so effective. They do not allow your personal opinion about whether you’re done dictate your effort.
We normally give up before we have pierced that thin veil between what we think is our maximum and what we can actually do.
Who of us had that coach ask us to do one more rep or run one more lap or make one more call or sing one more scale or repeat that stanza one more time?
We thought we were done, but we were, by no means, tapped out.
Again, I’m not sure of the math – if it’s 40% or 50% or 60%, but I’m sure that when we think we’re done, we’re not normally done. There’s more in the tank. Push harder. One more minute. One more rep. One more dial. One more.