Which factor most closely defines the body’s ability to change direction

The factor that most closely defines the body's ability to change direction is "agility."

Explanation:

When the body moves or changes the direction or even the position suddenly and also effectively under control is because of the body's ability to agility.  It needs some sudden reflexes, Co- ordination, balance, speed and also proper response to the changing situation. Some examples are forward running, dot drills, jump box drills, shuttle runs. Agility not also improve the athletic performance, whereas it also helps in improving the everyday activities.