Fitting Terms Glossary
Club head speed is the speed at which the clubhead is traveling at the moment of impact. This measurement is the best predictor of the distance a ball will travel. Every 1 mph of club head speed equates to approximately 2-3 yards of distance.
Attack angle is the vertical angle the club is traveling relative to the ground at impact. A negative Attack Angle means the club is striking down into the ball at impact, which is desirable with irons. A positive attack angle means the club is striking upwards into impact, which is usually desirable with the Driver.
Club path is the lateral angle, relative to the target line, that the clubhead is traveling at impact. A positive club path number indicates an inside-out swing. A negative club path number means the club is moving outside-to-inside at impact.
Swing plane is the angle made between the ground and the plane created between the clubhead and handle of the club at the bottom of the swing arc, as measured down the target line. The higher the value, the steeper the swing. The lower the value, the flatter (or less upright) the swing is.
Swing direction is the orientation of the swing plane to the target line at the lowest point of the swing. This concept is different from club path, which is measured at the point of impact.
Dynamic loft is the loft that is actually delivered to the ball at impact. This figure is influenced by the static loft of the club, shaft lean at impact, and the squareness of the clubface to the target-line. The higher the dynamic loft, the higher the ball will launch with added spin, and the slower the ball speed will be. The lower the dynamic loft, the lower the ball with launch, with less spin, and more ball speed.
Spin loft is the difference between the angle of attack and the dynamic loft. It is one of the numbers that can help explain back spin imparted on the ball. The lower the spin loft number, the lower potential for backspin, when also considering clubhead speed. The higher the spin loft, the higher the potential for backspin, when also considering clubhead speed.
Face angle measures the orientation of the club face at impact relative to the target line. If the figure is positive for a right-handed golfer, then the face is open relative to the target line. If the figure is negative, then the face is closed relative to the target line.
Face to Path
Face to path measures where the club face is at impact relative to the swing path. If the figure is positive for a right-handed golfer, then the face is open relative to the path. If the figure is negative, then the face is closed relative to the path.
Ball speed is a pretty simple term: It is the speed at which the ball is traveling when it leaves the club face. Ball speed is the primary contributors to the distance the ball travels, with launch angle and spin rate being close secondary factors.
Launch angle is the angle, as measured from ground level, that the ball launches at impact. In order to achieve ball flight, which is optimized, the preferred launch angle for a shot is dependent on the static loft of the club, combined with the golfer’s clubhead speed and typical attack angle.
Launch direction, measured relative to the target line, is a metric which measures how many degrees the ball launches offline.
Spin axis is the measurement of the axial tilt or the rotation of the ball due to impact with the club. A negative Spin Axis denotes a ball that will curve with “draw” or hook”. A positive Spin Axis denotes a ball that will curve with “fade” or “slice”. The Spin Axis of the ball is due to the face-to-path differential, and strike point on the face.
Spin rate is the amount of spin, as measured in RPMs, imparted on the ball at impact, a measure of all types of spin combined.
Smash Factor / Efficiency
Smash factor/efficiency is a ratio that is derived from dividing ball speed by club head speed. This is an index of efficiency which indicates how solidly the shot was struck.
This is a measurement of the total peak height of a shot at the highest point in the ball’s trajectory.
Carry is the measure of how far the golf ball travels in the air from impact to first landing on the ground.
Total distance is measured using the carry number and adding in the anticipated bounce and roll from a standard PGA Tour fairway at sea level, accounting for spin rate, landing angle and landing speed rate.
This indicates the total dispersion from the target line as the ball lands. If the number is positive, it measures a ball landing to the right of the target line. If the number is negative, it measures a ball landing to the left of the target line.
Side total indicates the dispersion from the target line after bounce and roll. If the number is positive, it measures a ball landing and stopping to the right of the target line. If the number is negative, it measures a ball landing and stopping to the left of the target line.
Landing angle refers to the angle at which, relative to the ground, the ball first lands and hits the ground after a shot. Lower lofted clubs will typically have a shallower landing angle compared to higher lofted clubs. Landing angle is determined by ball speed, peak height, and ball spin.