I listened to an interview with Jesse Itzler on The 5 AM Miracle podcast last week and after that I read a nice article about it as well. In short: Jesse met a Navy SEAL during a running race. He was so impressed with the guy that he invited the SEAL to live with him for a month, which turned out both as a curse and a blessing.
The SEAL taught Jesse about the 40% rule: this is moment your mind tells you that it is not possible to do more. Actually, you’re able to add 60% more than where you are. The math behind it doesn’t really add up, but I do like the concept.
Whenever you feel really tired, out of ideas, out of strength to do more, think about this 40% rule and push through. Your body will try to steer you towards easier things that give instant gratification, but if you break through, you’ll be amazed by how much more you can do.