The 40-30-30 rule...........

"To improve at anything, we must at some point push ourselves outside our comfort zone."

"Many of the strategies employed in competitive and recreational sports are applicable in business and our personal lives. One lesson I learned from alpine ski racing was the "40-30-30 Rule." During training, early on, I tried to go fast, and I also focused on not falling. On a ride up the ski lift, my coach told me I was missing the point. He explained that success in ski racing, or most sports for that matter, was only 40% physical training. The other 60% was mental. And of that, the first 30% was technical skill and experience. The second 30% was the willingness to take risks."

Both quotes excerpted from here.