In a previous article, we discussed how the dynamics of your pickleball paddle contribute to the speed, power, and accuracy of your shots. In particular, we discussed the importance of the paddle trampoline mode and its frequency relative to the diving board and anti-resonance modes. In practice, however, we have found that not all trampoline modes are equal, and thus the trampoline mode frequency alone is not an adequate indicator of paddle reactivity (or power). In this article we will re-visit paddle trampoline and diving board modes and show how certain paddles can generate more power based on characteristics of their trampoline modes. Let’s first look at the paddle diving board modes.
Diving Board Modes
One common misconception is that when contact is initiated with the ball, the paddle face bends backwards like a diving board, then flings the ball forward like a slingshot at the end of contact. This “whip action” effect has been studied extensively with baseball bats and golf clubs, with the following findings:
- For baseball bats, the frequency of the diving board mode is too low. High speed photography verifies that the ball will have already rebounded from the bat before the bat could spring back to its original configuration.
- For golf clubs, the club shaft flexes backward at the start of the downstroke, then springs forward as the head contacts the ball. This effectively increases the effective club swing speed, propelling the ball forward with increased velocity.
In our dynamic analyses of pickleball paddles we found that they behave more like baseball bats in that the paddle face bends backwards about the paddle throat when contact with the ball is initiated. However, the spring-back frequency of the diving board mode is too low (in relationship to the trampoline mode) to contribute much energy to the return of the ball. As shown in Figure 1, the relative amplitude of the diving board mode for most paddles is 3-5 times lower than the amplitude of the trampoline mode.
Our results verify the findings of other researchers who have studied diving board and trampoline (hoop) modes for conventional and metal baseball bats. We will therefore focus on the trampoline modes of pickleball paddles.
Trampoline Modes
In a previous article we performed modal impulse tests of several paddles and hypothesized that paddles can be classified according to the frequencies of their trampoline modes, as follows:
- Less than 500 Hz: Maximum reactivity (or power), but may exceed limits for the USAP Paddle/Ball Coefficient of Restitution (PBCoR) test.
- Between 500 and 700 Hz: High reactivity “Power” paddles.
- Between 700 and 850 Hz: Medium reactivity “Hybrid” paddles.
- Greater than 850 Hz: Low reactivity “Control” paddles.
On further examination, we now believe that using the trampoline mode frequency alone may not be sufficient to classify a paddle’s power. Rather, we must look at both the frequency and deformation shape of the paddle trampoline mode because certain trampoline deformation shapes will be more efficient in transferring power to the ball than others. To illustrate, let’s look at a few test results.
Classical Trampoline Bending (Figure 2) – In the classical trampoline bending mode, the paddle edge (or frame) appears to be rigid together with the handle, and the point of ball contact at the center of the paddle oscillates. For this particular paddle, the region of maximum deformation is tightly centered at the ball contact point, indicating that the dynamic sweet spot of the paddle is relatively small. Players may find that they can generate a lot of power by hitting the ball at the paddle face center but may lack power by hitting the ball off center.
Figure 2. Classical Trampoline Bending
Taco Bending (Figure 3) – This mode is characterized by the paddle face folding along the longitudinal (handle) axis, causing the edges to “flap” like a soft taco shell. This deformation shape is a result of the paddle frame lacking rigidity across the top edge and bottom shoulders. As described above, a Classical Trampoline mode requires the paddle face sheets to oscillate between a rigid frame. The Taco Bending mode is therefore less efficient in transferring energy to the ball since energy is wasted by the flapping motion. Players may also find a loss of power if they contact the ball off of the paddle longitudinal axis.
Figure 3. Taco Bending
Potato Chip Bending (Figure 4) – This mode is characterized by the paddle face folding along the transverse or lateral axis, causing the paddle face to deform into the shape of a potato chip. This deformation shape is a result of the paddle lacking rigidity along the sides. Like the Taco Bending mode (Figure 3), the Potato Chip mode is less efficient in transferring energy to the ball than the Classical Trampoline mode since the lateral bending wastes energy. Furthermore, players may find a loss of power if they contact the ball too high or too low along the paddle longitudinal axis.
Figure 4. Potato Chip Bending
Asymmetric Bending (Figure 5) – If the ball contacts the geometric center of the paddle face, it will normally cause the greatest dynamic deformation to occur at the geometric center. However, Figure 5 shows that the greatest dynamic deformation occurs off-center, which is an anomaly. Further investigation found that this particular paddle had a delaminated face sheet due to an inadequate amount of adhesive used during manufacturing. The asymmetry and loose face sheet results in a significant loss of power and unpredictability of your shots. This illustrates how the modal impulse test is useful not only to predict a paddle’s reactivity (or power) but to detect potential paddle damage.
Figure 5. Asymmetric Bending
Optimum Trampoline Bending – Figure 6 shows what we consider to be the Optimum Trampoline bending mode. Here, we can see that the paddle frame is somewhat rigid and the entire region from the paddle geometric center towards the outward edges of the paddle undergo the maximum deformation. This paddle would be considered to have a large dynamic sweet spot and would be forgiving if the ball is hit off-center. Use of this paddle on the court verified that it could generate a considerable amount of power, yet shots were well-controlled and predictable.
Figure 6. Optimum Trampoline Bending
Future Articles
In this article we showed some different characteristics of paddle trampoline vibration modes and how these characteristics related to the efficient transfer of power from the paddle to the ball. In future paddle reviews, we will categorize the paddle’s power potential by knowing the deformed shape of its trampoline mode and the frequency that this mode occurs.
