The following is an excerpt from Tim Grover's book "Relentless" --
Because no matter what you want for yourself, whether
your ambitions take you to the gym or the office or anywhere else you want to
be, your ultimate power source will come from the neck up, not the neck down.
In sports, we spend so much time on the physical component—training, working,
and pushing the human body to be fast and stronger and more resilient than most
people ever thought possible. And then eventually, we get around to paying some
peripheral attention to mental conditioning. That’s completely backward.
Excellence isn’t only about hitting the gym and working up a sweat; that’s the
smallest part of what you have to do. Physical ability can only take you so
far. The fact is, you can’t train your body—or excel at anything—before you
train your mind. You can’t commit to excellence until your mind is ready to
take you there. Teach the mind to train the body. Physical dominance can make
you great. Mental dominance is what ultimately makes you unstoppable. You will
never have a more powerful training tool than this: get your mind strong, so
your body can follow.