You're Correct!

How you swing the golf club around you on your back swing, down swing and follow through influences how consistent, accurate and long you are as a golfer.

The angle that you swing the golf club around you at, or specifically the angle that you swing the club head around you at, is known as your swing plane. Every golfer has an optimum swing plane individual to them and the golf club that they are using. If they swing the club head around them on this plane, or at that specific angle, then the golf club head approaches the golf ball at the optimum angle to produce a consistent connection, a straight golf shot and maximum shot length.

A golfers swing plane is quite easy to discover if you use an alignment pole. Simply take up your address position with a golf club. Place the alignment pole into the ground so that the pole enters the ground in line with the club head. Push the pole in at an angle that replicates the angle that the shaft of the golf club has created with the ground. This is your swing plane. If you take a good step to the left of the pole, for right handed golfers, to swing on plane you need to swing the club head back around you so that the club head follows the alignment pole. If you swing the club head back around you underneath or below this alignment pole then you have a flat golf swing and the club head is moving around you on too low an angle. When this happens, the club head approaches the golf ball too much from the inside of the target line, on too much of an arc.

This results in the club head swinging across the target line rather than down and along it and causes you directional issues with your golf shots. The fact that the club head is at a lower angle also means that you will have issues with achieving a consistent strike on the golf ball. The club head will tend to connect with the ground before it connects with the golf ball and you will hit a fat golf shot that does not fly very high or travel very far.

A flat golf swing causes the club head to approach the golf ball too much on the inside of the target line. This means that the club head travels across the target line rather than along it, resulting in shots that fly right of the target, or shots that curve right to left during their flight.

A flat golf swing means that the club head travels around you at a very low angle. Due to the low angle that the club head is moved around you on, at the top of the back swing the club head is in a low position, not a high one.

A flat golf swing causes you a variety of swing problems. It makes it difficult to achieve a consistent connection and it is very difficult to control your ball flight to be accurate with your shots. An on plane swing is the best swing to have.