We’ve long been taught that the two main aspects of the ball flight laws are clubhead path through impact and clubface angle at impact. These are the two main focal points of most teaching, because a clubface angle that is square to the clubhead path at impact will produce a dead straight shot…or so we’ve been taught.

Before we go any further, let’s look at the five aspects of the ball flight laws:
• Clubhead path through impact
• Clubface angle at impact
• Centeredness of clubface contact
• Angle of approach
• Clubhead speed

Assuming a square clubface angle to the clubhead path at impact, what could possibly happen, besides an outside force such as the wind, to make the ball not go straight? The answer to that would be failing to contact the ball on the club’s “sweet spot,” or center of percussion. Technically, the sweet spot is only a small point on the clubface, so if a ball is not perfectly or close to perfectly struck on this spot, a reaction known as “gear effect” takes place. Basically, the ball rolls or attempts to roll toward the center of percussion if it is not perfectly struck. Here is what happens when the four general areas around the sweet spot – above, below, on the toe and on the heel – strike the ball:

Above: Virtually every shot with any sort of decent contact will have backspin, so a ball struck here will not produce topspin. But it will reduce the amount of backspin, unless the club is descending at such an angle at impact that the golfer only contacts the lower part of the ball, in which case a pop-up with lots of backspin results (usually with a driver, fairway wood or hybrid; doing this with irons is rare). Hitting the ball above the sweet spot is important to produce long drives, so drivers are manufactured with a very low sweet spot in most cases. Irons hit appreciably above the sweet spot will produce shots with greatly reduced distance.

Below: A large increase in backspin will result, unless the ball is skulled or topped.

On the toe: This is where gear effect becomes extremely noticeable. High-speed video shows that balls hit on the toe of the club result in a clubface that twists open, sometimes severely, upon contact. Since the ball will want to roll towards the center of percussion, hook spin results. Launch monitor data show that toe strikes with a square clubface and path result in a hook the majority of times, and can even overcome an open clubface to the point of still producing a hook! On other occasions, if the toe strike is especially severe or the player has weaker hands, the clubface can open to an extent that it results not in a hook but a more severe fade or slice. This is not as common as a draw or hook with a toe strike, but it has been shown through the GC Quad launch monitor, which has the capability of “seeing” where on the clubface the ball was struck.

On the heel: As with toe strikes, heel strikes have noticeable gear effect, with fades and slices resulting. Here as well, heel strikes can produce fades and slices even when the clubface is closed to the clubhead path at impact. Although heel strikes often close the clubface at impact, they do not normally make a hook worse, according to GC Quad data. This is due to the heel being closer to the shaft than the toe, which means lack of hand strength isn’t as much of a factor as it can be with toe hits.

So, how can we use all of this in our teaching? It’s important to see where the student is striking the ball on the clubface so we can determine if something else is causing an errant ball flight besides clubhead path and clubface angle. With a driver, impact stickers or foot powder spray do the trick nicely. Impact stickers tend to also work on irons when hitting off of grass, and will always work on artificial turf mats. Foot powder spray may not work very well with irons hit off the grass.

If clubhead path and clubface angle are the two main aspects of the ball flight laws, then centeredness of contact is a close, and in fact a very close, third. Some teachers even argue that it’s the most important, because without striking the clubface squarely nothing else matters. Whatever your position, pay attention to this most important aspect of the ball flight laws.
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