The following is a great passage from the book "Toughness" written by Jay Bilas which speaks to the mindset of a player in regard to practice.
How many players start practice with the intention or goal
of simply “getting through” practice? Instead of “getting through” a workout,
players need to “get from” a workout-to get the most from it, and the most from
themselves. No player ever got better by just getting through something. True
toughness is competing through the end of a practice or workout after having
prepared yourself mentally to compete. That is a key mind-set of the toughest
players.
