One U.S. Navy SEAL has formalized this idea into something many call the 40 percent rule. That is, when your mind says you’re done, you’re only 40 percent done.
That SEAL is named David Goggins, and some call him the toughest man alive: he’s an Ironman triathlete who finished fifth in the 135-mile Badwater Ultramarathon in Death Valley and once held the record for most pull-ups completed in 24 hours.
Mind Over Matter
This inspirational principle comes to us not directly from the Navy SEALs themselves, but from a California billionaire. Jesse Itzler, founder of Marquis Jet and husband to Sara Blakely, the founder of Spanx, was running a 100-mile relay in San Diego with six other people when he encountered a 200+ pound Navy SEAL running the entire race on his own. Itzler swears the man had broken all of the bones in his feet and given himself kidney damage, but finished the race anyway. Itzler did what any billionaire worth his salt would do: he paid Goggins to live with him for a month and teach him his ways.
Things got serious on the very first day Goggins came to live with Itzler. Itzler said that the first thing Goggins did was ask him how many pull-ups he could do. Itzler recounted, “I’m not great at pull-ups. I did about eight…He said, okay, take thirty seconds and do it again. So thirty seconds later I got up on the bar and I did six, struggling. He said, all right, one more time. We waited thirty seconds, and I barely got three or four, and I was done.” But he wasn’t done. Goggins told him they weren’t leaving until he did 100.
Itzler thought it was impossible, but he kept trying, one at a time—and eventually succeeded. “…He proved to me right there that there’s so much more, we’re all capable of so much more than we think we are.” Thus, the 40 percent rule. “He would say that when your mind is telling you you’re done, you’re really only 40 percent done.”
Though the 40 percent rule is mostly backed by anecdote, there is some scientific research to support it. A number of studies have found that the placebo effect has a big impact on sports performance. That is, if you think something will improve your performance, it probably will. That suggests that a good portion of your strength and toughness is mental, not physical. For example, a 2008 study published in the European Journal of Neuroscience found that when you give people a sugar pill and tell them it’s caffeine, then have them lift weights, they can work significantly harder.
So whether or not the 40 percent rule is truly scientifically accurate, you can consider it your sugar pill. The next time you think you can’t do any more, remember that you probably can.
“The US Navy Seals have a theory that no matter how bad we feel or how tired we get, we’re actually nowhere near the limit of what we can achieve; the brain is deceiving us to save the body from pain. In fact, they think we’re only 60 per cent there.
The 40% rule isn’t really a rule. Rather, it’s a way of saying that you have much more left in your reserve tank than you think, even when it feels like you’ve reached the limit of what you’re capable of.
Brain Training Improves Physical Performance
Marcora has also done some research with the British Ministry of Defence, to see if “brain training” can improve physical performance in soldiers.
In the 12-week study, soldiers were assigned to one of two groups. Both groups did one hour of cardio on an exercise bike, three times a week. However, one of the groups performed a mentally fatiguing task while they pedaled.
At the end of the study, both groups showed similar increases in V02 max, a common indicator of physical fitness.
However, when the soldiers were asked to do a “time to exhaustion test,” where they rode at a specific percentage of their VO2max until they couldn’t continue, there was a marked difference in performance.
The control group saw their time to exhaustion improve by 42 percent. However, soldiers who combined physical training with mental exercise improved by 126 percent, three times as much as the control group.