Poor arc can happen for a number of different reasons ranging from positions the player is in at their set point, or directions of moves with certain parts of the body.
The shooting hand can end up on the back of the ball at the set point, the ball can get onto the palm, the shoulders can lean back. These will all create a flat shot to varying degrees.
But one of the most common will be the elbow of the shooting hand.
Two different things can happen with the elbow that would cause a flat shot.
First, the elbow can get above the eyes before the player even starts the shooting motion. If they do this, the ball usually goes over their head, and the shooting motion tends to pivot around the elbow, causing a forward/downward release.
Second, the shooting hand elbow can stall and not get over the eye level until the ball is already out of the shooters hand. A lot of coaches will talk about “get your elbow above the eyes” but WHEN that occurs is critical. The elbow needs to get above the eyes as the ball is leaving the shooters hand, not before or after. To make this happen, players need to get to their set point (whether they are a one or two motion shooter) and make sure the elbow is lifting up before the hand starts moving forward. The two motions are really close together, and you won’t be able to see it with the naked eye without a lot of practice, but if you look on slow motion video, I would hope the elbow would start lifting out of the set point about 2 frames of video (or 2/30th of a second) before the hand starts moving forward.
Young players do this poorly (not really their fault, its just the reality of playing basketball when you aren’t very strong) and if you watch video of most young players shooting from the side, you’ll see them pushing the ball forward well before the elbow starts to lift. Sometimes the elbow only starts to lift after that ball leaves their hand.
So I end up cuing players by telling them to lift their “elbow, then wrist”. You’ll hear me say that a lot. “Hand under ball, elbow then wrist.”
