I’ve always wondered what exactly is the difference between spin, control, and power focused racquets. Below is the result of my own research into it all, and some educated assumptions on my part.
Physics of Hitting a Tennis Ball
The ball and tennis racquet both have some initial momentum before the hit. The racquet then transfers the forward momentum to the ball depending on how elastic the collision is in the forward direction. The racquet also transfers upwards momentum and spin to the ball depending on the how elastic the collision is in the lateral direction, and how much friction there is between the racquet and ball.
Racquet Strength Definitions
It’s important to understand what is meant by a racquet giving more control/spin/power.
Spin
The spin of a racquet is how much spin you impart on the ball with respect to the lateral speed of the racquet.
Control
The control of a racquet is your ability to influence the outgoing ball trajectory by adjusting your swing.
A racquet with high control will give more maneouvreability to let you position the racquet exactly how you want to.
A racquet with high control will also be less affected by
- The incoming speed of the ball; and
- The incoming spin of the ball.
Power
The power of a racquet is how much speed you impart on the ball with respect to the forward speed of your tennis racquet.
Racquet Properties
Forward Elasticity
This is how elastic the hit is in the forward direction. Increased forward elasticity gives
- Increased Power: Less kinetic energy loss gives more speed to the ball.
- Decreased Control: More elasticity means more of the ball’s own forward momentum is used.
Lateral Elasticity
This is how elastic the hit is in the lateral direction. Increased lateral elasticity gives
- Increased Spin: Less kinetic energy loss in the lateral direction gives more spin to the ball.
- Decreased Control: More lateral elasticity means more of the ball’s own spin and vertical momentum is used.
Time on String Bed
This is how much time the ball stays on the string bed.
Lateral Friction
This is how “grippy” the strings are to the ball. Increased lateral friction gives
- Increased Control: Increased lateral friction lessens the impact of the incoming spin of the ball.
- Increased Spin: Increase lateral friction increases how much spin you can put on the ball.
Balance
This is, for a given overall racquet weight, whether the racquet has more weight towards the head (head heavy) or handle (head light). A more head heavy racquet gives
- Increased Power: More of the weight is towards the head, so with the same racquet head speed more momentum is imparted to the ball.
- Decreased Control: Increased head weight decreases the maneouvreability of the racquet.
- Decreased Spin: Increased head weight decreases the maneouvreability of the racquet, which decreases the amount of lateral speed you can produce with it. This decreases the spin imparted to the ball despite the gain in inertia in that direction.
Overall Weight
This is simply how heavy the racquet feels. A heavier racquet gives
- Increased Power: More weight = more momentum.
- ? Control: Increased weight decreasing maneouvreability but increases stability.
- Decreased Spin: Increased weight decreases the maneouvreability of the racquet, which decreases the amount of lateral speed you can produce with it. This decreases the spin imparted to the ball despite the gain in inertia in that direction.
Giving Racquets Desired Properties
So, based on the previous section, we have that:
- Control racquets want low elasticity in both directions, high lateral friction, and head light balance.
- Spin racquets want high lateral elasticity, high lateral friction, head light balance, and a low overall weight.
- Power racquets want high forward elasticity, head heavy balance, and a high overall weight.
Racquet manufacturers have a number of ways to achieve these things (I’m setting head size at 100in):
-
RACQUET FEATURES
- Frame Stiffness: Increasing frame stiffness increases forward elasticity by not allowing the frame to flex much, making the strings do the flexing.
- Grommets: So called “spin grommets” allow the strings to move more laterally, increasing lateral elasticity.
- String pattern: The more dense string pattern, the less forward elasticity and lateral elasticity.
- Balance: Racquets can put weight wherever required to adjust the balance.
- Mass: More mass in the racquet, the higher the overall weight.
Before we talk about specific strings, there’s potentially the most impactful feature:
- String tension: Increasing string tension decreases both forward elasticity and lateral elasticity.
String choice does also affect things, but not as much as the racquet and string tension:
-
STRING FEATURES
- Thickness/Gauge: Increasing the thickness of a string decreases both forward elasticity and lateral elasticity.
- Material: Different string materials give different properties. Simplifying it HEAPS, you choose either poly or non-poly. Poly strings give more lateral friction at the cost of decreased elasticity.
Racquet Features to Strengths
I won’t include string type in here, because I don’t believe it has too much of an impact.
| Feature | Spin | Control | Power |
|---|---|---|---|
| Frame Stiffness | - | Low=1, High=-1 | Low=-1, High=1 |
| Grommets | Spin=1, Regular=-1 | Spin=-1, Regular=1 | - |
| String pattern | 16x18=2, 16x19=1, 18x20=-1 | 16x18=-2, 16x19=-1, 18x20=1 | 16x18=1, 16x19=1, 18x20=-1 |
| Balance | HL = 1, HH = -1 | HL = 1, HH = -1 | HL = -1, HH = 1 |
| Mass | ‘Light’ = 1, ‘Heavy’ = -1 | - | ‘Light’ = -1, ‘Heavy’ = 1 |
| String tension | Low = 1, High = -1 | Low = -2, High = 2 | Low = 2, High = -2 |
My racquet (Pure Aero+) scores:
- Spin = 4
- Control = -2
- Power = 0
I very much enjoy the spin it gives, but I might want to up the control a tad. A more average stiffness frame like the Yonex Vcore would even out control and power while still keeping the spin.