Feb. 22 marks 31 years since the U.S. Olympic hockey team upset the Soviet Union en route to the gold medal.

Those of us old enough to remember saw the jubilation and the celebration on the ice. But no one saw the hard work behind the feat. Except the players. They will never forget. After living through it, they know the way Coach Herb Brooks constantly kept them on edge, not letting them relax for a minute.

“If Herb came into my house today, it would still be uncomfortable,” captain Mike Eruzione said years after the event, now known as the Miracle on Ice.

Eruzione knows all about the uncertainty. Not long before the Olympics, Brooks let it be known that anyone could be cut — even the team captain. If the captain could be cut, then who could ever take it easy? Who could be comfortable? No one.

“If you give 99 percent,” Brooks said, “you will make my job very easy.” No platitudes about giving 110 percent. Brooks knew the difficulty of giving even 90 or 95 percent. He pursued it like a fanatic, looking for mental, physical and emotional edges.

“He messed with our minds at every opportunity,” defenseman Mike Ramsey said of his coach.

Brooks wasn’t the only coach to recognize the need to keep things on edge. Anson Dorrance, head coach of the renowned University of North Carolina women’s soccer team, makes his players compete on the practice field and in the weight room.

He says that if your practices run too smoothly, you’re probably practicing things you already know. To prod even more effectively, Dorrance posts the results of the competition so everyone can see them.

Sports psychologist Dr. Rob Gilbert says, “You’ve got to become comfortable being uncomfortable.”

The soul of effective practice — deliberate practice — is to work just outside the area of competence.

“Move out of your comfort zone,” says self-help author Brian Tracy.  “You can only grow if you are willing to feel awkward and uncomfortable when you try something new.”

Brooks made sure everyone had that feeling.