By TrackMan Master – Chris Reimann – PGA Professional, Germany
Using TrackMan and Statistics from “Every shot counts” to determine what to train.
Being a Computer scientist and a PGA Professional, I always wonder if you can combine statistical knowledge with TRACKMAN data to determine what to train with your golf students. You always have a general feeling if you should train distance or direction/accuracy but you can never be sure if you are really correct in your decision, this article gives you a recommendation how to decide.
In general, training for distance is a huge advantage, the top 10 in driving distance on the PGA Tour in 2017 include names such as Rory McIlroy, Dustin Johnson, Brooks Koepka and Justin Thomas. So your main aim should be to train for distance since 1 mph in clubhead speed leads to 3 yds more distance with your driver given optimal launch and spin values.
Youth training should also involve a lot of clubhead speed improvement training no matter if accuracy is lost sometimes. Since a developing player will always adjust for the improved clubhead speed with more accuracy over time.
But when you have more golf balls in a lake or trees than on the fairway you cannot play a decent round. So the big question is when do you train for accuracy and when do you train for distance?
The following paragraph gives a detailed background on how the parameters are calculated. If you are not interested in detailed statistics you can skip this part and go directly to the chapter “analyze your shots”.
Calculations and statistical analysis
Given a shot and recording its “total” and “side total” value with TRACKMAN, you can calculate the angle that the ball is left or right of target by: ∝ = 𝒂𝒓𝒄𝒔𝒊𝒏 (𝒔𝒊𝒅𝒆 𝒕𝒐𝒕𝒂𝒍 [𝒊𝒏 𝒚𝒅𝒔 𝒐𝒓 𝒎] / 𝒕𝒐𝒕𝒂𝒍 [𝒊𝒏 𝒚𝒅𝒔 𝒐𝒓 𝒎])
Mark Broadie in his book “Every shot counts” has analyzed golfers with playing levels of 80 to 110 shots per round and PGA Tour Pros. In his book, he has analyzed their angle of deviation.
- An average PGA Tour pro has a deviation angle of 3.4°
- Wildest Drivers on PGA Tour 3.7° to 4.4°
- Players with a score of 90 strokes per round have an average deviation angle of 6.5°
So theoretically it is possible to calculate the deviation angle for every shot if you measure “total” and “side total” of a shot with TRACKMAN. If you are lower than the average angle for your player type then you should train for distance and if you are higher you should train for accuracy.
For example, if you have a 90-strokes per round player and a drive of 200yds “total” and 18yds “side total” this would give you an angle of 5.16° which is below the average of 6.5° accuracy. This means you should train for distance since this player is too accurate and is losing strokes by not having a longer drive.
More specifically the paper “Assessing Golfer Performance Using Golfmetrics from Mark Broadie (page 4&5, Figure 2) ” lets you determine if a player is more accurate than the average or less accurate than the average. He is using the following equation with 𝜎(𝛼) being the standard deviation depending on the angle and 𝑑0.75 being the 75% percentile of distance for several shots.
𝜎(𝛼) = −0.0315𝑑0.75 + 13.223
Players below this linear equation would train for distance and players above would train for accuracy. This equation is later on used in figure 2 to determine what to train, figure 2 is based on the graphical illustrations of the paper on page 5. Since every shot is different in “total” and “side total”, the paper also gives you an indication of what shot you have to measure. It is the 75% percentile of your shots. This means if you have 5 shots of 255,250,240,200 and 60 yds you would take the second longest shot with 250yds and “side total” for that shot for your calculations. This equation can be used in general to measure tee shots with Drivers, Woods or Irons.
Expected score improvement
What improved score can you expect when you hit longer tee shots with a certain accuracy? Broadie shows in his paper that for a certain distance and a standard deviation in direction you can expect better results.
|75% tee distance||Std. dev direction|
|Pro (64-79)||272 m / 297 yds||4.0|
|Am1 (70-83)||227 m / 248 yds||5.4|
|Am2 (84-97)||217 m / 237 yds||6.4|
|Am3 (97-120)||198 m / 216 yds||8.1|
Additionally, in his book Broadie estimates how much a player would get better if either the accuracy is improved, or the distance is improved. Here one can clearly see that additional distance outweighs accuracy, especially for golfers with higher scores. A player in the ‘115 strokes scoring range’ would increase their score by 2.7 strokes when gaining 20 yds off the tee. Although this does not mean that distance always outweighs accuracy.
|PGA Tour||80 golfer||90 golfer||100 golfer||115 golfer|
|Strokes per 18m/20yds||0,8||1,3||1,6||2,3||2,7|
|Strokes per degree||0,8||0,9||0,9||1||1,1|
Let’s assume another example illustrated in the fairway picture if you have a tee shot of 240 yards and you are within a range of 6 degrees deviation with your tee shot you will be accurate enough based on the statistics of all golfers. A 6-degree deviation is a side total of 23 yds on each side. A 6-degree deviation would be exactly at the edge of this imaginary fairway target. If you hit more accurate shots on average, you could focus on gaining distance if you hit less accurate shots you should focus on accuracy.
You probably don’t want to stand on the range and start calculating shots. In order to make the process of determining the deviation angle of a shot more convenient I have created a table which gives you the angle of the shot when you have “total” and “side total”. In the following the process of analyzing your shots is explained in every step, this was just the statistical background.
Analyze your shots
You can measure every tee shot with this method, it doesn’t matter if it’s a Driver, Wood or Iron, but you have to make sure that the target is a fairway.
Take 5 shots with your driver and let TRACKMAN record “total” and “side total”. All tables and diagrams are in yards and also in meters, so you can record whichever you are used to. Just be careful to stay in one system.
Choose the second longest drive, for example, if you have 5 shots of 237,235,233,227 and 220 m you would take the second longest shot with 235m (this shot has a “side total” value of 12m in our example). This would mean you have an angle of 3° according to the table.
|Distance in [m]||3°||4°||5°||6°||7°||8°|
Table 1: Distance in meter
|Distance in [yds]||3°||4°||5°||6°||7°||8°|
Table 2: Distance in yds
Then use the following graphic to determine which area you should work on.
- If your point with “total” and angle is below the amateur baseline you should work on distance since the player is too accurate.
- If your point with “total” and angle is above the amateur baseline you should work on accuracy and direction since the player is losing strokes by being too inaccurate.
In our example 3° and 235m “total” you can determine what area you should work on since this point are below the amateur baseline, this player should work on gaining more distance.
You have to consider that if you are very close to the line you should always go for distance since distance always outweighs accuracy and more accuracy can always be trained with a faster club speed later on.
You should repeat this measuring process of 5 shots for at least 3-4 times to get an accurate result, so you need approximately 15 to 20 Drives. You can repeat the complete process in multiple training sessions to account for different daily performances of your player. If you are always on one side of the chart you can be pretty certain that you can work on this aspect.
Start your training
If you decide to start training for distance a good starting point would be to improve clubhead speed. If you have the highest possible clubhead speed you would start to improve launch angle and spin rate. Since those are heavily influenced by the attack angle and your body motion. I would suggest that you try to optimize a stable body movement and attack angle first. As soon as all those parameters are improved you would improve the smash factor since this can be easier optimized with a stable body movement.
If you decide to start training for direction a good starting point would be to improve clubface control and club path since this generates “side spin” and is the main factor for deviation. In my opinion clubface control is heavily influenced by your grip and should be fixed first. After you have fixed your grip a stable motion for Club path should be found. If you have good clubface control and club path you can start to improve center hits since gear effect also generates deviation. Center hits can be created with a stable body motion much easier.