Summer is the offseason for golf in Arizona because of the heat, and for that reason, I like to have a to-do list of goals to get me through those slower months. There are afternoons in the Golf Shop when you can go 2-3 hours without seeing or hearing from a soul. One my goals this summer was to learn more about TrackMan’s launch monitor technology and to go through their online certification program, TrackMan University.
Everything is done through the TrackMan University web site or the company’s very slick mobile app, which features a black graduation cap with an orange tassel. Your training starts in the Game Room where there are ten fundamentals tutorials to help you learn the basics of impact and ball flight.
After that, there are three course management tutorials designed to help you understand how weather and environment affect ball flight and then four definitions (intended for Coaches) to discover the meaning of the TrackMan vocabulary.
The self-paced tutorials feature everything from slides and infographics to videos and actual Trackman training sessions with real PGA and LPGA Tour pros. The training is free, up to a point. If you decide you want to become TrackMan Certified, the cost is $475 for one year of TrackMan Platinum Membership, which unlocks the Level 1 and Level 2 Certifications Tests through the app. I decided not to take the plunge, but I took copious notes during every one of the tutorials up until that point. I’ve attached those notes here:
Distance
High launch and low spin are optimal for maximizing driver distance. If a driver club speed changes, spin rate, ball speed, and launch angle will also change.
A golfer’s optimal ball speed, launch angle, and spin rate are primarily dictated by club speed and attack angle.
When a golfer has a negative attack angle, more loft is needed to launch the ball high. Increasing the loft without changing the attack angle generates more spin and reduces the smash factor due to the greater spin loft.
Increasing attack angle also helps launch the ball higher. This method increases the launch angle while keeping the spin loft low, and this controls the spin rate while providing a higher smash factor. The end result: more ball speed, a better launch angle and spin rate, and greater carry.
As club speed decreases, a higher launch and more spin are required to optimize carry due to less lift and drag on the golf ball at lower speeds. As club speed becomes very low, the optimal spin will slowly begin decreasing. Spin rate has less effect on the trajectory at low speeds. Launch angle becomes the primary factor for optimizing distance.
The golfer’s club speed and attack angle have a big influence on their optimal launch conditions. Increasing attack angle is a good way to increase a golfer’s potential distance. The more positive the attack angle, the higher the driver smash factor will be when optimized for distance.
For a given club speed and attack angle, increasing dynamic loft will increase spin rate. If a golfer’s attack angle becomes more positive, then their optimal ball speed will be higher.
Smash Factor
The club speed value used to calculate smash factor is measured at the geometric center of the club head.
Smash factor = ball speed / club speed
To increase ball speed, it is more important to improve centeredness of contact than to increase club speed. An increase of 3 mph of ball speed will generate approximately 6 yards of distance with the driver (1 mph = 2 yds.).
An off-center impact is less efficient in transferring energy from the club to the ball.
Spin Rate
Spin rate is generated primarily by club speed and spin loft. There are many factors that affect spin rate: club and ball design, friction, and impact location.
Spin loft is the wedge created by the direction the club head is moving and the orientation of the cub face at the time of maximum compression. If the club face is pointing in the same direction as the club head is moving, then there would be no spin assuming center contact.
As spin loft increases, spin rate increases. Club speed also has an effect on spin rate.
2.1 x club speed (mph) x spin loft (degrees) = driver (expected spin rate factor = 1.9-2.2)
2.9 x club speed (mph) x spin loft (degrees) = irons (expected spin rate factor = 2.8-3.0)
Impact location, in particular on the driver, can change the expected spin rate significantly. Impact high on the club face can reduce the expected spin rate as much as 1,000 rpms. Impact low on the club face can increase the expected spin rate as much as 1,000 rpms.
Changes in the friction between the club and the ball will also affect the spin rate. Moisture, grass, dirt, face tape, and other substances will change the expected spin rate value.
Dynamic loft – attack angle = spin loft (Ex: 15.5° dynamic loft minus -1° attack angle = 16.5° spin loft)
Ball type and spin loft directly influence spin rate.
According to Jason Dufner, launch angle should be close to one-half the loft of the club. Spin rate should be close 1,000 rpm for every number on the club (7i = 7,000 rpm). Height should be about the same for the entire bag (PW-3i). You stop the ball with spin rate and land angle.
A spin loft of 12.5° (vs. 9.1° or 11.2°) will generate the highest spin rate. A club speed of 125 mph will generate the highest spin rate. A lower club speed will generate a lower spin rate.
Attack angle and club path make up the direction the club head is moving at a specific point in time (ie. the club head’s direction at maximum compression).
Spin loft is the three-dimensional angle between the direction of the club head’s movement and the club face’s orientation at the time of maximum compression. It is largely responsible for the smash factor and spin rate of a golf shot.
If the face to path value is 0°, then spin loft is the difference between dynamic loft and attack angle. As the face to path value becomes larger, the actual spin loft will have a greater value than the simplified calculation of dynamic loft minus attack angle because spin loft is a three-dimensional angle.
The greater the difference between the dynamic loft and attack angle, the lower the smash factor and the higher the spin rate.
Decrease spin loft to generate higher ball speeds and lower spin rates.
Low friction will decrease the spin rate. High friction will increase the spin rate.
Higher club speeds will generate higher spin rates.
Face angle and dynamic loft make up the direction the club face is pointing at a specific point in time (ie. the club head’s orientation at maximum compression).
Launch Angle
Dynamic loft accounts for approximately 75% of the launch angle for a 6-iron.
Dynamic loft = 18°
Attack Angle = -6°
6i Launch Angle = 12°
Dynamic loft has a greater influence than attack angle on the launch angle of a golf shot. Several factors influence the dynamic loft of a golf shot including where along the arc impact occurs and the golfer’s position at impact.
Adjusting the amount of loft presented to the golf ball at impact is the most direct route to changing the launch angle. At impact, the direction the club is moving (attack angle) and the direction the face is pointing (dynamic loft) are the two main factors that will influence the launch angle.
The ball will always launch in between the dynamic loft and the attack angle. If the two are equal, then the ball will launch in the same direction. For the driver, dynamic loft has roughly a 4x greater influence than attack angle. For an iron, dynamic loft has roughly a 3x greater influence than attack angle.
Club and ball construction as well as friction are other factors that can make this ratio vary slightly. Dynamic loft accounts for 80% of launch angle for a driver and 75% of launch angle for a 6-iron. As the club’s loft increases, the influence of the dynamic loft is slightly diminished. Changing the dynamic loft has a substantial effect on the launch angle for the driver and irons.
The static loft, the point on the arc impact occurs, and the angle between the lead arm and shaft all influence the dynamic loft. Any bending (flexing) of the shaft can also have a small impact on this value. A higher impact point on the driver increases dynamic loft. A lower impact point on the driver decreases dynamic loft.
For clubs with roll (vertical) on the face, the vertical impact point will also change dynamic loft. Dynamic loft has the greatest influence on the launch angle of the golf ball and therefore is an important component to controlling the height of a golf shot.
To increase the launch angle of his driver, at set-up, Kevin Streelman tees the ball up higher and plays the ball more forward in his stance to allow for a more positive attack angle on the way up.
The launch angle will move closer to the dynamic loft if friction becomes low relative to a shot with normal friction.
Dynamic loft = the vertical angle of the club face at the center-point of contact between the club and the ball at the time of maximum compression.
Launch angle = the vertical angle the golf ball takes off at relative to the horizon and measured immediately after separation from the club face.
Attack angle = the up or down movement of the club head’s geometric center at the time of maximum compression.
For a high-lofted wedge, attack angle accounts for approximately 30% of the launch angle.
Launch Direction
Club path has less influence than face angle on the launch direction of a golf shot.
A positive club path = inside-out for a right-handed golfer.
Launch direction always falls in-between club path and face angle assuming they are not equal. If the two are equal, then the ball will launch in the same direction. Launch direction is closer to face angle than it is to club path.
Club path = the in-to-out or out-to-in movement of the club head’s geometric center at the time of maximum compression.
Face angle accounts for approximately 70% of the launch direction with a lob wedge.
At impact, the direction the club is moving and the direction the face is pointing are the two main factors that will influence the launch direction.
For the driver, face angle has roughly a 4x greater influence than club path. For an iron, face angle has roughly a 3x greater influence than club path.
Club and ball construction as well as friction are other factors that can make this ratio vary slightly. The face angle accounts for around 80% of the launch direction. That value for a 6-iron is 75%.
As the club’s loft increases, the influence of the face angle is slightly diminished.
The club path must be changed significantly in order to see a real difference in the launch direction. Changing the face angle has a substantial effect on the launch direction.
Impact location directly affects face angle, which in turn directly affects the launch direction.
When in trouble, make sure the face is pointed at the edge of the obstacle and the path is outside that point. This will guarantee the ball’s launch direction will not be pointed at the obstruction.
Depending on the type of curve you want, you shift your body lines but aim the face where you want the ball to start, and then you shift your body lines to get the curve.
Launch direction = the horizontal angle at which the golf ball takes off relative to the target line and measured immediately after separation from the club face.
The launch direction will move closer to the face angle if friction becomes low relative to a shot with normal friction.
Attack angle is the point in time of maximum compression where TrackMan reports attack angle. The attack angle will be very close to zero if the club head’s geometric center aligns with the horizon of the golf ball.
Attack angle is an important factor in controlling the trajectory and maximizing distance of any golf shot.
Face angle = the direction the club face is pointing relative to the target line at the center-point of contact between the club and ball at the time of maximum compression.
Club Path
Darren May (Kevin Streelman’s Coach) likes swing direction to be half of the attack angle to get the club path down to a small number.
If you hit a ball before the bottom of the arc (attack angle hitting down) that’s how you get a rightward swing direction. In conjunction with a rightward club path, this will produce a draw.
Attack angle and club path are measured at the time of maximum compression. Swing plane and swing direction are measured during the bottom portion of the swing arc.
-4.4° swing direction = left (for a right-handed player)
Better players touch the ball before they touch the ground. In order to take a rightward path and make it (the ball) go straight, you have to change your swing direction to the left. The swing direction is left, but now you can get your club path nice and straight.
During the downswing, the club head is moving along an arc and in a downward motion as it is approaching the golf ball. The up or down movement of the club head can be described by a line that is tangent to the arc at a specific point in time.
Club path = the in-to-out or out-to-in movement (relative to the target line) of the club head’s geometric center at the time of maximum compression of the golf ball.
The club path will be very close to zero if the blue arrow aligns almost perfectly with the target line.
Club path is a key factor in the direction and curvature of a golf shot.
Swing direction, swing plane, and attack angle all have a direct effect on club path
Face angle, dynamic loft, and club speed all have an indirect or no effect on club path
For a Right-Handed Golfer:
* If swing direction is negative and attack angle is 0, then the club path must be negative (left)
* If swing direction is 0 and attack angle is negative, then the club path must be positive (right)
* If swing direction is negative and attack angle is positive, then the club path must be negative (left)
* If swing direction is 0 and attack angle is positive, then the club path must be negative (left)
* If swing direction is positive and attack angle is positive, then the club path cannot be determined
* If swing direction is positive and attack angle is negative, then the club path must be positive (right)
* If swing direction is positive and attack angle is 0, then the club path must be positive (right)
* If swing direction is negative and attack angle is negative, then the club path cannot be determined
For a Left-Handed Golfer:
* If swing direction is 0 and attack angle is negative, then the club path must be negative (right)
* If swing direction is 0 and attack angle is positive, then the club path must be positive (left)
How much will the club path change if the attack angle changes by 1°?
Swing plane > 45° = club path changes less than 1°
Swing plane = 45° = club path changes 1°
Swing plane < 45° = club path changes more than 1°
45° swing plane, 0° swing direction, 4° attack angle = -4° club path
For a swing plane of 63° (7-iron), the ratio of the change for attack angle to club path is 2:1 (attack angle:club path).
Changing swing plane and swing direction will change the club path.
Swing direction = the angle between the base of the plane created by the club head’s geometric center movement and the target line.
Swing plane = the vertical angle between the plane created by the club head’s geometric center movement and the horizon.
Swing plane and swing direction are measured during the bottom portion of the swing arc.
If the attack angle and swing direction are both zero, then the club path must be zero (assuming a swing plane of 50°).
For a right-handed golfer, assuming a 45° swing plane and a 0° swing direction, the attack angle is 5° if the club path is -5°.
For a right-handed golfer, assuming a 45° swing plane and a 0° swing direction, the club path is -2° if the attack angle is 2°.
For a right-handed golfer, assuming a 45° swing plane and a 0° swing direction, the club path is 3° if the attack angle is -3°.
For a right-handed golfer, if swing direction is 0 and attack angle is 0, then the club path must be 0.
Spin Axis I
For a right-handed golfer, a negative spin axis would be described as a draw/hook (right to left). Think of the wings of an airplane.
If the wings are level to the ground, the plane is going to fly straight ahead. If the face to path number is negative, the ball will draw (face is closed to the path). If the face to path number is positive, the ball will fade (face is open to the path).
The golf ball spins around one axis. The greater the spin axis value, the more curvature on the shot.
For every 10° of tilt in the spin axis, the ball will curve approximately 14 yards to the side at 200 yards and 7 yards to the side at 100 yards. For every 5°, the ball will curve approximately 7 yards to the side at 200 yards.
Spin Axis II
The amount of change in tilt in the spin axis created by an off-center impact of .5” is greatest in the driver followed by a hybrid and then an iron.
For a right-handed golfer, the spin axis assuming center contact with a face angle of 3° and a club path of 3° is a push.
Face to Path:
-17.7°= spin axis -20.5°
-15.6° = spin axis -18.3°
-13.5° = spin axis -16°
-1.2° = spin axis -1.5°
Just because the face to path is a certain number, we really need to take into account where we’re making impact on the club face. That could actually override what the shot shape should have been.
Anytime the face to path is negative but the spin axis is positive, that indicates a heel hit for a right-handed golfer. That closing of the club face imparts gear effect, which will get the ball to curve to the right.
Off-center impact and face to path have a direct effect on spin axis
Low point, swing direction, and swing plane have no effect on spin axis
Gear effect is responsible for the toe hook and the heel slice.
The amount of horizontal gear effect depends on the depth (further back = more tilt) of the center of gravity (CG) of the club head, moment of inertia (MOI), amount of off-center impact, ball speed, and launch direction.
Bulge was designed into drivers so that the ball would finish closer to the target line. The bulge changes the face angle on off-center impacts, which influence the face to path and the launch direction.
The spin axis tilt produced by the gear effect outweighs the tilt from the face to path. Golfers with higher club speeds need more bulge than slower club speeds due to the ball speed’s roll and gear effect.
On irons, a blade’s center of gravity (CG) is closer to the club face, and therefore, there is minimal gear effect.
If the face is delivered closed to the path with an iron, the gear effect will only minimize the amount of draw created by the face to path differential, and the shot will still have a negative spin axis tilt.
If you find the right balance of CG and MOI, the net effect will create a very playable shot. Not only will a larger cavity back iron help with minimizing distance lost on off-center hits, it will also make mishits have smaller dispersion. Gear effect can be a good thing!
For a pitching wedge with a face to path of 1°, which spin loft will generate the greatest spin axis assuming center contact? 38.1°
The greatest tilt in spin axis (in order): -9.5°, 6.8°, -4.3°, 2.9°
For a driver:
Face to path -9.5° = spin axis of -30.5°
Face to path 4.2° = spin axis of 14.7°
Face to path 8.7° = spin axis of 28.4°
Face to path 8.9° = spin axis of 28.9°
For a 6-iron:
Face to path -11.1° = spin axis of -22.5°
Face to path -3.1° = spin axis of -6.6°
Face to path 2.9° = spin axis of 6.2°
Face to path 12° = spin axis of 24.1°
The smaller the spin loft, the greater the tilt in the spin axis when face to path is non-zero assuming center impact.
If clubs have the same spin loft, they will have the same spin axis.
For a right-handed golfer, impact towards the heel will create a positive spin axis assuming 0° face to path.
If face angle and club path are the same, the spin axis value will be 0° assuming center impact.
A driver has more horizontal gear effect than an iron because the CG is further from the club face.
For a left-handed golfer, impact towards the heel will create a fade or slice assuming 0° face to path. Impact towards the toe will create a positive spin axis assuming 0° face to path. A negative face to path value will generate a fade or slice assuming center contact.
For a 6-iron with a face to path of 1°, a spin loft of 22.9° (vs. 26.7° or 25.5°) will generate the greatest spin axis assuming center contact.
For a driver with a face to path of 1°, a spin loft of 7.8° (vs. 10.2° or 15.1°) will generate the greatest spin axis assuming center contact.
Straight Shot
0° club path, 0° face angle = center impact for a straight shot
In-to-out club path, closed face angle = heel impact
Out-to-in club path, open face angle = toe impact
There are three scenarios (methods) for hitting a straight shot that travels in a straight line to the target:
Method 1 (center impact)
Club path = 0°
Face angle = 0°
Longest carry
Method 2 (heel impact)
Club path = positive
Face angle = negative
Shortest carry
Method 3 (toe impact)
Club path = negative
Face angle = positive
Middle carry
The spin axis for straight shot Method 2, which has the least efficient carry, is 0°. The launch direction for straight shot Method 3, which has the 2nd most efficient carry, is 0°.
Bounce & Roll
A flatter land angle will increase the amount of bounce and roll.
Hard surface = most amount of bounce and roll
Soft surface = least amount of bounce and roll
Land angle, landing ball speed, ground hardness, and landing spin rate directly affect the amount of bounce and roll.
The landing ball speed for a given player is nearly the same for all full shots.
Higher landing spin rates will generate less bounce and roll.
At higher altitudes, a tailwind will increase the amount of bounce and roll because the landing angle will be flatter and the landing speed will be faster.
A shot to an uphill target will increase the amount of bounce and roll because the landing angle will be flatter.
Wind
A headwind will not change the spin rate.
A headwind hurts more than a tailwind helps. In fact, at higher wind speeds, a headwind will hurt more than twice as much as a tailwind helps. A tailwind will create a lower max height (apex).
When you hit into a headwind, your shots carry shorter, fly higher, and land steeper due to lift (what makes the ball rise) and drag (what slows the ball down).
Under calm conditions, the air is moving into the golf ball at the speed the ball is traveling. When there is a tailwind, the wind speed subtracts from the airflow. A headwind adds to the airflow. The faster the airflow, the greater the amount of lift and drag, which is why you see the ball balloon when hitting into the wind.
It’s a common misconception that a ball spins more when hit into a headwind. Actually, it’s the extra lift created by the added airflow that gives this impression.
More spin also creates more lift and drag. Into a headwind, spin is the enemy. Trying to swing harder is not the answer. Swinging harder likely creates more club speed, which creates more spin. Instead, use a club with less loft to optimize for the conditions, and hit the ball the correct distance, reduce the spin loft, and therefore, reduce the spin rate.
A shot with two little spin in a tailwind will turn that ballooning shot into one falling to the ground because lift also keeps the ball in the air.
A tailwind will produce shots that carry longer, fly lower, and land flatter. Although you can use a higher-lofted club to create more spin, the best bet is to launch the ball higher so that it will land steeper and stop more quickly.
Lift and drag do not behave linearly to air flow. That is why a headwind hurts more than a tailwind helps.
Tailwind
Increases carry
Decreases height and land angle (less lift and drag means the ball will apex lower and land flatter)
No change to ball speed, spin rate, or launch angle
Headwind
Decreases carry
Increases height and land angle (due to greater lift and drag, the ball will fly higher and land steeper)
No change to ball speed, spin rate, or launch angle
A headwind creates a greater change (delta) compared to carry under calm conditions.
For a shot that starts straight (zero launch direction) and has no curvature (zero spin axis), a right-to-left wind will create a side value that is to the left (negative). A left-to-right wind will create a side value that is to the right (positive).
Weather
A higher temperature will decrease max height (apex). A lower temperature will increase max height (apex).
Temperature, humidity, and air pressure all affect air density. Denser air creates more resistance for the golf ball. The greater the air density, the more lift and drag. This means greater air density results in shots that fly higher, land steeper, and carry shorter.
Although wind and altitude have much larger effects on distance, changes in the weather can result in noticeable gains and losses. Lower humidity will decrease carry. Lower humidity, lower temperatures, and higher air pressure will increase air density.
An 8° change in temperature will affect land angle the most. A change in temperature will affect land angle, apex, and carry.
As elevation increases, air pressure decreases, but for a given location, weather patterns will create small changes in air pressure.
High pressure systems increase air density, and lower pressure systems decrease air density. However, the differences are unlikely to create a noticeable change in your ball flight. Normal changes in air pressure will result in less than one yard difference in distance.
Higher humidity will make the ball fly farther. Even though humid air may feel heavier, the molecular weight of water is less than that of dry air, which consists primarily of nitrogen and oxygen. Higher humidity decreases air density.
Even though humidity does affect air density, going from 10% to 90% has negligible effects on distance (less than 1 yard to a mid-trajectory 6-iron and just over 1 yard to an optimized drive).
Temperature changes will have the greatest effect on distance. Going from 40° F to 100° F will increase a mid-trajectory 6-iron by almost 8 yards and the driver by 9 yards. That is a little more than 1 yard per 10° F. This distance increase is only due to temperature’s effect on air density.
Low air pressure, high humidity, and hot temperatures will result in a combination of weather conditions that decrease air density and make the ball fly lower and farther but no more than a club difference. A higher temperature will increase carry.
A higher temperature will decrease land angle. Higher humidity will slightly decrease height. Higher humidity and lower air pressure will decrease air density. Lower humidity will slightly increase land angle. A lower temperature will decrease carry. Temperature will affect carry the most. Higher air pressure will slightly increase height and land angle. Lower air pressure will slightly increase carry and slightly decrease height.
Elevation
All else equal, a shot hit to a downhill target will have less bounce and roll than a shot to an uphill target.
Some range finders contain an inclinometer that measures how far uphill or downhill a target is located.
At 30 feet downhill, the differences in land angle (30’, 45’, or 60’) would cause the carry distance to be more than 10 yards different by the time a shot reaches the ground.
The ball that carries the farthest will also have the flattest land angle, causing the total distances to be even farther apart.
At a 30° land angle, for every 1 foot, yard, or meter the target is downhill, the ball will carry roughly 1.75 feet, yards, or meters farther. At a 45° land angle, the ratio is 1:1. This is the adjustment most golfers use. A 60° land angle, which is steep, is typically only seen if there’s a headwind.
Playing distance is the carry flat value the golfer should try to achieve when the target is uphill or downhill.
Shots hit to an elevated green will have a flatter land angle, which can generate a lot of bounce and roll. Shots hit to a downhill green will have a steeper land angle (less bounce and roll). Shots hit to uphill targets lose a little more carry than the amount gained to downhill targets.
Land Angles: For Uphill Shots:
High = 60° High = straight-line distance + (.6 x uphill distance)
Mid = 45° Mid = straight-line distance + (1 x uphill distance)
Low = 30° Low = straight-line distance + (1.8 x uphill distance)
For Downhill Shots:
High = straight-line distance – (.6 x downhill distance)
Mid = straight-line distance – (1 x downhill distance)
Low = straight-line distance – (1.8 x downhill distance)
Shots to uphill targets will typically have more bounce and roll than shots to downhill targets.
In general, the ball will carry shorter at lower altitude. The ball will land flatter at higher altitude and land steeper at lower altitude. The ball flies 10% farther at high altitude, but the average gain is only 6%. On the PGA Tour, the largest gains are with a 6-iron, 7-iron, and 8-iron, but the average gain is still below 10%.
At higher altitudes, the lower air density creates less lift and drag. This means the ball will fly farther but apex lower and land flatter.
The lower trajectory will cause the ball to miss the golfer’s window. The flatter land angle will cause the ball to release more than normal.
An elite-level golfer will typically adjust by launching the ball higher, which increases their land angle. This higher launch angle generally increases carry at the high altitude. For someone with Tour Pro club speed, the altitude and higher launch angle adds up to 10%.
Golfers can also use club design to help at higher altitudes. Compared to an iron, a hybrid is designed to launch the ball higher, which makes it apex higher and land steeper. Not only will the hybrid provide a little more carry, it will also make it easier to stop the ball on the green. And this holds true for all altitudes.
With the driver, tee it high and let it fly!
Increasing attack angle and optimizing ball speed, launch angle, and spin rate at high altitude can produce dramatic distance gains. Altitude will have varying effects for a golfer depending on their club speed and trajectory.
After apex, the land angle will continually become flatter.
Club – Part I
Club speed is measured and reported just prior to first touch between the club and ball.
Dynamic loft, club path, attack angle, and face angle are all measured and reported at maximum compression.
During impact, the when is typically described as first touch, maximum compression, or separation. The where can be described as the front of the face, center of the club, or back edge. It can also be described as the heel or toe. The when and where selected will affect the club delivery measurements. When is the point in time at which the parameter is measured. Where is the physical location at which the parameter is measured.
TrackMan reports club delivery measurements at the time of maximum compression and at the geometric center of the club head.
Club speed, attack angle, and club path are measured at the geometric center of the club head. Dynamic loft and face angle are measured at the center-point of contact.
Dynamic loft and attack angle are measured relative to the horizon. Club path and face angle are measured relative to target line.
Club speed is measured relative to the direction the club is traveling just prior to impact.
Attack angle = vertical movement of the club head at impact
Club speed = the speed of the club head
Dynamic loft = the angle of the club face relative to the horizon
Face angle = the angle of the club face relative to the target line
The average driver attack angle on the LPGA Tour is 3°. The average driver attack angle on the PGA Tour is -1°. The average driver club speed on the LPGA Tour is 94 mph. The average driver club speed for the male amateur is 94 mph. The average driver club speed on the PGA Tour is 113 mph. The highest verified club speed ever recorded by TrackMan is 156mph (Connor Powers at the Quarterfinals of the 2014 World Drive Championship). An increase in 1 mph in club speed will create a distance gain of 3 yards with the driver.
For a right-handed golfer:
Positive face angle = open
Negative face angle = closed
0° face angle = square (or neutral)
A negative attack angle would be described as hitting down on the golf ball. The standard assumption attack angle for the pitching wedge is determined by mid-trajectory and 72 mph club speed (assumed club speed for a pitching wedge based on the average male golfer). Mid-trajectory is always assumed for non-driver shots.
Trajectory type along with the club speed is used to determine the optimal attack angle.
The standard assumption attack angle for a 6-iron is determined by mid-trajectory and 80 mph club speed.
For a right-handed golfer:
Positive club path = in-to-out
Negative club path = out-to-in
0° club path = square (or neutral)
The standard assumption used for a driver club speed of a male golfer is 94 mph.
The average driver attack angle for the male amateur golfer is -2°. On average, as a golfer’s handicap goes up, the attack angle becomes slightly steeper. However, this does not mean that a high handicapper will always have a negative attack angle.
The standard assumption used for a 6-iron face angle is 0°.
Driver Standard Assumptions
Club speed = 94 mph
Attack angle = 0°
Dynamic loft = 15.6°
Ball speed = 137 mph
Launch angle = 13.6°(conditions optimized for max carry with a 0° attack angle)
Spin rate = 2772 rpm
Face angle and club path are 0°
6-Iron Standard Assumptions
Club speed = 80 mph
Attack angle = -3.2°
Dynamic loft = 28.7°
Ball speed = 110.4 mph
Launch angle = 16.9°(conditions optimized for a mid-trajectory)
Spin rate = 5956 rpm
Face angle and club path are 0°
Pitching Wedge Standard Assumptions
Club speed = 72 mph (based on average male amateur)
Attack angle = -3.9°
Dynamic loft = 44.6°
Ball speed = 85.6 mph
Launch angle = 26.7° (conditions optimized for a mid-trajectory)
Spin rate = 8408 rpm
Face angle and club path are 0°
Club – Part II
For a right-handed golfer, a negative face to path value means the face is closed to the path.
Face to path = the difference between the measured face angle and the measured club path.
Face to path = face angle – club path
Face angle and club path are reported at the time of maximum compression
The smaller the face to path value, the less curvature you will see for center struck shots.
For a left-handed golfer, a negative face to path value means the face is open to the path. A positive face to path value means the face is closed to the path.
Swing plane = the vertical angle between the plane created by the club head’s geometric center movement and the horizon.
Low point = the distance from the club head’s geometric center to the lowest point on the swing arc at the time of maximum compression.
Face to path and spin loft use the center-point of contact between the club and ball as part of the measurement.
Spin loft, the direction the club face is pointing, is comprised of face angle and dynamic loft. Both of these use the center-point of contact as part of the measurement.
Face to path, spin loft, and low point are measured at maximum compression. Swing direction and swing angle are measured during the bottom portion of the swing arc. Face to path, spin loft, low point, swing direction, and swing plane are measured at the geometric center of the club head. Face to path and spin loft are measured at the center-point of contact.
Swing direction is measured relative to the target line. Swing plane is measured relative to the horizon. Face to path, spin loft, and low point are measured relative to other things.
Swing direction, swing plane, and low point are measured at the geometric center of the club head. Face angle and dynamic loft are measured at the center-point of contact between the club and ball. Spin loft and face to path are measured at both the geometric center and the center-point of contact.
Less than 100 points of the club head’s position during the bottom portion of the swing arc are used to measure swing angle.
TrackMan measures swing angle based on the movement of the club head’s geometric center during the bottom portion of the swing arc from approximately knee high on the downswing to knee high after impact with the points prior to impact weighted more heavily. The loft of the plane created by these points relative to the horizon is the reported swing angle. Longer clubs such as the driver generally have a lower (or flatter) swing angle value, whereas shorter clubs will have a higher (or steeper) value. Other factors such as height and posture at impact can affect swing angle.
Spin loft is a three-dimensional angle.
Attack angle and club path make up the direction the club head is moving at a specific point in time (i.e. the club head’s direction at maximum compression).
Spin loft components:
Club head’s movement = attack angle, club path
Club face’s orientation = dynamic loft, face angle
Dynamic loft and face angle make up the direction the club face is pointing (club face’s orientation).
A low point that is reported as “before” will always have a positive attack angle.
Spin loft only equals dynamic loft minus attack angle if the face to path is 0°.
A dynamic loft of 58.2°minus -9.2° attack angle = 67.4° spin loft assuming face to path is 0°.
For a right-handed golfer, a negative swing direction can be described as “over the top.”
Launch
Smash factor = the ratio between the measured ball speed and measured club speed.
Smash factor = ball speed / club speed
Smash factor provides an indication of how solidly a shot is struck.
TrackMan measures club speed just prior to first touch.
The maximum smash factor achievable is limited by the COR of the club, which is sometimes referred to as the “trampoline effect.”
Other components that affect smash factor: the club head’s mass, the ball’s mass, and spin loft.
A centered impact with low spin loft will help maximize smash factor and increase distance.
Ball speed, smash factor, launch angle, launch direction, spin rate, and spin axis are measured immediately after the club and ball separate.
Ball speed, smash factor, launch angle, and launch direction are measured at the geometric center of the ball.
Spin rate and spin axis are the imaginary lines the ball rotates around.
For launch direction, if the value is negative, the ball starts to the left of the target line for a right-handed golfer. If the value is positive, the ball starts to the right of the target line for a right-handed golfer.
Launch angle and spin axis are measured relative to the horizon.
Launch direction is measured relative to the target line.
Ball speed is measured relative to the direction that it is traveling immediately after separation.
The greater the spin axis value, the more curvature on the shot.
For a right-handed golfer, a positive spin axis value means the ball will curve to the right. A negative spin axis value means the ball will curve to the left. The bigger the value, the greater the curvature (ie. slice or hook).
Spin axis = the angle relative to the horizon of the imaginary line that the golf ball rotates around and is measured after separation from the club face.
Spin axis describes the amount of curvature on a golf shot. The direction the club head is moving, the direction the club face is pointing, and the impact location all contribute to the resulting spin axis. Spin axis along with launch direction create the 9 different ball flights.
The average driver ball speed on the PGA Tour is 168 mph. The average driver ball speed on the LPGA Tour is 140 mph.
Spin loft and face to path are used to determine the spin axis when using TrackMan in the indoor setting (ball flight less than 30 yards).
For a left-handed golfer, a positive launch direction is described as a pull. A negative launch direction is described as a push.
When using TrackMan in the outdoor setting (ball flight more than 30 yards), the club delivery measurements are not used to determine spin axis.
TrackMan sometimes refers to spin rate as total spin.
Spin rate = the rate of rotation of the golf ball about the imaginary line the golf ball rotates around (spin axis) measured immediately after separation from the club face.
Spin rate is one of the three launch components to maximizing distance.
At impact, the speed of the club and impact conditions influence the amount of spin generated.
Although the spin rate decreases throughout flight, TrackMan reports its maximum value, which is immediately after the ball leaves the club face.
Spin rate is primarily influenced by club speed and spin loft.
A gain of 5 mph of ball speed with the driver will equate to approximately 10 yards of added distance.
Back spin and side spin can be calculated using the spin rate value and spin axis value. Spin rate has the same value as the back spin component when the spin axis is 0.
Ball flight is used to measure the spin axis when using TrackMan in the outdoor setting.
A heavier club head will increase smash factor. A heavier golf ball will decrease smash factor.
The highest ball speed verified by TrackMan is 226 mph (Connor Powers, 225.9 mph, Quarterfinals of 2014 World Long Drive Championship).
When using TrackMan in the indoor setting, the club delivery measurements of club path, face angle, dynamic loft, and attack angle are used to calculate spin axis.
Flight
Maximum height and apex are alternative names for the parameter height.
Height = the maximum height (apex) of the trajectory measured relative to the elevation at which the golf ball was launched.
The greater the height of a golf shot, the steeper the land angle.
Total Distance = carry + bounce and roll
Carry can also be referred to as carry flat since it is the carry value if the ground were flat.
Carry = the straight-line distance between where the golf ball was launched from and where it crosses a point that has the same elevation.
Side total = the distance from the target line to where the ball comes to rest.
Side and side total are measured relative to the target line.
Land angle is always measured relative to the horizon.
Land angle = the angle the golf ball lands relative to the horizon and at a point that has the same elevation as where it was launched.
The shallower the land angle, the more bounce and roll for a golf shot.
Height and land angle are measured relative to the horizon (the elevation the ball is launched from).
Side and side total are measured relative to the target line.
Carry and total are distance measurements using two points that both lie on the horizon/same elevation.
Carry and side use the carry flat point as part of the measurement.
Side is not the distance from the target line to the calculated bounce and roll point.
Side = the perpendicular distance between the target line and where the trajectory crosses a point that has the same elevation as where the golf ball was launched. It is sometimes referred to as dispersion. It can also be referred to as side flat.
The average driver carry on the PGA Tour is 276 yards. On the LPGA Tour, the average driver carry is 224 yards. The average driver carry for the male amateur golfer is 208 yards.
A negative side total value indicates the ball’s calculated resting position is left of the target line.
Total uses landing spin rate, land angle, landing speed, and assumed ground hardness to calculate the expected bounce and roll.
Total = the straight-line distance between where the golf ball was launched from and its calculated resting position.
Carry actual refers to the straight-line distance between where the ball was launched and where it lands.