To perform a dip, the exerciser hangs from a dip bar or from a set of rings with his arms straight and shoulders over his hands,
then lowers his body until his arms are bent to a 90 degree angle, and then lifts his body up, returning to the starting position.
Short people are able to cope better with a narrower grip, but not with a wider one. Tall people have greater ease in this exercise
overall as their reach to chest size ratio is greater.
Due to natural flexibility in the shoulder joints, it is important to try to "lock" them as much as possible during this exercise.
Otherwise, the supporting rotator cuffs may become strained. -Wiki-