Understanding the Importance of Impact Location Part 2 - Spin! December 09 2015
If you’re the type of player who is looking to spin the ball more with your wedges it’s important to understand the nature of spin and how it’s best produced. A number of factors such as club quality, ball quality, interference from foreign material and impact location are all important, as you can see I am going to focus on impact location alone in this blog.
The graphic from testing using Foresight GC2 with HMT below illustrated three different impact locations with the other variables kept as similar as possible such as attack angle, delivered loft and speed (which was kept with a 2mph window). The intent was to only adjust impact location which isn’t as easy as it sounds without adjusting those other variables!
As you’ll quickly notice the shot with the most spin came from the lowest impact location and the shot with the least spin came from the highest which was pretty much the C.O.G of the club head. The differences are significant and important to comprehend so here we go!
There are two key spin generating factors that rely on impact location, the first being vertical gearing. Gear effect as a phenomenon is found on all golf strikes, whether it be a driver when it’s at it’s most severe or a wedge and it’s the vertical gearing that enhances the interaction between club face and ball. You’ll see that despite the highest spinning shot also having the highest delivered loft it had the lowest launch, this in part due to the vertical gearing which pulls the flight down and it works more effectively with the cover of the ball. The second and perhaps lesser know factor at play here is the attack angle, you might wonder where this is going but stay with me.
The attack angle on shots hit below the C.O.G of the club head is likely to change DURING the impact interval, in this low face contact instance it dives further downwards thus adding to the downward pull of the club face against the ball cover thereby increasing spin even more.
So now you know why low impact location increases spin how should you go about achieving it? First of all lets address something crucial to low impact location and that is the lie of the ball, if it’s sitting on hard pan low impact is unavoidable, you couple that with zero interference from the grass (as there isn’t any) and you have a perfect storm for spin. Problem is that’s hard pan and you probably don’t get to hit off it that often. The main issue when grass is introduced to the equation is the space you now have underneath the golf ball, the more space you have the harder low face contact becomes. As always you have choices as to how to try and get it right. The first is to look for a more level attack angle, you could either do this by raising the butt of the club into impact thereby canceling out the downward trajectory of the club head. Alternatively you could release the shaft to somewhere near vertical by impact, this is ensuring both a level attack and no low dynamic loft. The main problem that a more level attack angle produces is that of increased interference between club and ball so all that hard work to lower the impact location is quite easily undone by friction killing grass! So what’s a player to do? My preferred option is to keep enough downwards in the attack angle to reduce interference and release the shaft fast, there are many keys to doing this successfully though… maybe enough for another blog post.