Despite what you may have heard, your backswing can be too slow. The backswing sets up the downswing, and if you swing too slowly, you will not develop enough clubhead speed to hit the ball a long way. But there is no one correct speed; some players like Ernie Els appear to have slow backswings, while others like Nick Price have fast ones. The correct swing speed for you depends on several factors
Temperament is often mentioned when discussing swing speed. Players who typically act quickly tend to have faster overall swings (and therefore faster backswings), while very deliberate players tend to swing more slowly. While your temperament is an important aspect, it only indicates how fast you might want to swing. There are other considerations that are more important, because they place physical limits on what you can do.
Much more important in determining the speed of your backswing is how strong you are. Coiling properly at the top of your backswing requires a certain amount of physical strength; the stronger you are, the faster you can do it and remain in control. Players with slighter builds generally find that a slower backswing allows them to get into position more consistently, which in turn results in a more consistent shot.
Change of Direction
When you reach the top of your backswing and change direction, several things happen. Your wrists finish cocking and the clubhead starts to slow down, but its momentum resists you as you begin your downswing. To make this move with a faster backswing requires a lot of strength; if you swing back too fast, you will get twisted out of position at the top and have more difficulty making an accurate shot.
Your clubs also affect your backswing speed. At the top of the backswing, when you change direction, you “load the shaft”--you make it flex. This flex adds power to your shot, but a backswing that is too slow may not load the shaft properly. Technology has given us lighter, more flexible equipment, and a good club-fitter will take your backswing into account when you are fitted for clubs.
While you will generally want to make the quickest backswing that you can control well, there is one practical use for a slow backswing. While you will want to play with a good tempo, you may want to use a slow backswing for some of your practice swings, both on the practice tee and on the course. A slow backswing aids you in developing balance and strength, so consider one for practice swings and the driving range and a quicker backswing when you play.