I cannot start this without first disputing the phrase mentioned in the title. “Keep your head down” is a poor phrase that I hear all too often. The student that gets this advice will either eliminate rotation or continue to move their head up and down even though it is their intent not to. Please keep in mind, when someone tells you that your head is moving up and down, it is your spine that it moving the head. It is not your neck getting longer and shorter.
One of the top three problems that I see in students is a change in the angle of the spine relative to the ground. The change can occur either during the backswing or the forward swing. A normal golfer with good posture will have an angle of 35 to 45 degrees. As the swing starts and the golf club works towards the top of the swing if this angle changes and becomes more vertical we have a change in spine angle and now the player will have to start making adjustments and compensations in order to get back to the ball and maintain balance.
If the spine significantly changes angles during the swing it severely compromises a golfer’s ability to make consistently solid contact and produce consistent results. If during the swing the player significantly changes the angle of the spine relative to the ground, he or she is in fact moving the action of hitting the golf ball to different locations during the swing. Now we know why this game can be so difficult! If the spine angle moves towards vertical during the backswing, the player will have to do something to go and find the ball during the forward swing. Likewise, if the spine angle is changing during the forward swing, the player will have to make adjustments in order to find the ball.
As nature would have it, the most common swing fault also generally requires the most work to overcome. Because the list of physical requirements encompasses many different body parts the fix is seldom a simple one.
As in the C-posture, everyday life works against us. A weak core, tight hamstrings, immobile hips are all common as almost nobody addresses these areas. This applies not only to middle-aged adults but also to many of the teenagers I coach as well.
One of the screens we use in the physical assessment is called the Overhead Deep Squat. The athlete holds a bar or a golf club above their head and then performs a squat. Done perfectly, the club remains over the head, the squat is low enough for the thighs to move below parallel, the spine is parallel to the shins and the heals remain on the ground. This is a first level screen. By first level I mean that the initial screen will show where in the body the restriction(s) are. From there, we must dig deeper to ascertain a path to fixing the issues.