Ball Speed vs Spin: Racquet Movement
Understand why we get Power
Power Potential: At each location the ball will bounce off the racquet at the indicated percentage of its impact speed. Shot speed is the sum of the bounce speed plus the racquet speed at the impact point.
Shot Speed: The indicated speeds for each location are the results of a standard impact: ball speed=30 mph, racquet tip speed = 65 mph, angle of impact = 90 degrees using the Power Potential at each impact location.
Hittingweight: This is the effective weight of the racquet involved in the hit of a tennis ball at this location. The entire weight is never involved unless you hit right at the balance point, which usually isn't in the string plane.
Plowthrough Index: The percentage of racquet velocity remaining after impact. The lower the number, the more velocity is lost, which means the racquet head (and your arm) experiences a larger deceleration during the 5ms of impact. The higher the number, the more the racquet "plows through" the ball without slowing down as much. A negative number means the racquet location is actually going backwards, not just going slower!
Power/Hittingzone Size: The Power Zone is the total area under each colored curve. The Hitting Zone is the measured area under each colored curve AND above the gray 19-inch line. Each zone is indicated as the area in which the Power Potential is greater than 20%, 30% or 40%. This gives you an idea of over how great an area and to what degree your shot will feel solid.
Vibration Frequency: This is the number of times per second your racquet handle moves back and forth in your hand after impact. Vibration depends on both material stiffness and mass — since bending is movement. It is the best indicator of "dynamic stiffness" — what you actually feel during and after impact. A higher number is stiffer, a lower one is more flexible.
Shot Trajectory with Racquet: Knowing what we know about the racquet, we can plot the shot trajectory for any given input paramteters. For this shot: hitting height = 4 ft., ball speed = 30 mph, ball angle in = -5 deg., racquet tip speed = 65 mph, racquet swing angle = 30 deg., racquet tilt = 5 deg.