Visual Concentration
When you commit an error on an easy ground ball or miss a shot putt, it may be that you are distracted by things that ar happening around you. Our eyes normally react to anything that happens in our field of vision... spectators, other participants and even the wind blowing leaves on an overhanging branch. Visual concentration is the hability to screen out these distraction and stay focused on the ball or the target.
To improve your concentration, practice your sport while a friend is standing nearby waving his or her arms and moving at erratic intervals. You can also practice in the darkened room with a strobe light pulsating slowly. These excercise can hepl your eyes to remain fixed on their target in spite of other movement around you.