The perkinje cells tells your body what movements are right and wrong, for example if one tries to shoot a freethrow with one hand their brain will send a signal telling them that is wrong. This is why players develop specific routines while shooting free throws, their routines usually consist of an action not done in a live exhibition. Players usually make an unusual routine to tell their brain that they are shooting free throws, therefore triggering muscle memory. This muscle memory should tell the player how to shoot the free throw correctly. Good free throw shooters rarely change their routine, if a change is made the player is usually a bad shooter or the rules have changed. Some examples of muscle memory in free throw shooting in the NBA are Russle Westbrook who has shot over eighty percent every year but one in his career. His routine consist of him walking back to half court after every foul shot, but now the rules have changed not letting Russle complete his routine. That rule change has caused Russle to shoot only seventy two percent this year. Another example of is Lebron James, King James has never been spectacular from the line, and many attribute this to his constant change in free throw routine. Last year Lebron shot his worst percentage ever at an abysmal sixty seven percent. Lebron was said to of changed his routine three times last. These are two clear examples of muscle memory affecting free throw