Flying Elbow
This is a term used to describe the trailing elbow leaving the trailing side on the backswing. It is not necessarily a fault and many great players play golf with this motion. It can however affect the efficiency of the golf swing as it can create some sequencing issues on the backswing and downswing. The trailing elbow will fly away from the trailing side as the club reaches the top of the backswing, with the elbow pointing well behind the student. On most golfers the elbow points to the ground at the top of the backswing which would put the arm in a position to support the club at the top of the swing. However many great players have a flying elbow and still manage to get the arm in the correct position on the downswing to provide stability and power to the club.
You can diagnose the flying elbow from the target line view by watching to see if the trailing elbow is pointing behind the player at the top of the backswing position.
Body Preps
Physical Parameters Causing Flying Elbow and How to Diagnose Them:
The flying elbow can be caused by several physical limitations. First and foremost, any shoulder joint or soft tissue mobility restrictions in the shoulder girdle will limit the range of motion in the trail side shoulder. Maintaining a freely mobile shoulder joint is paramount for proper mechanics in the upper extremities. Any thoracic spine limitations can also indirectly limit the shoulder range of motion. Since thoracic spine limitation are usually coupled with loss of scapular stability, this can force the shoulder joint into positions that will limit external rotation and cause the elbow to fly.