tl;dr:An outdated way of thinking about peak performance is to think that “maximum effort = maximum results.” Research shows that it doesn’t work in reality. Here’s what works: The 85% rule suggests that to reach maximum output, you need to refrain from giving maximum effort. Operating at 100% effort all of the time will result in burnout and less-optimal results. While the precise number 85% may just be a rule of thumb, it’s a helpful one for managers who want to create high-performance teams without burning people out.