Foam Core Paddles Explained: Materials, History and PBCoR of Gen 4 Paddles

Coach Yoshi

Owner of Pickleball Lab

Published October 24, 2026

About 29 min read

17970 characters

Foam Core Paddles Explained: Materials, History and PBCoR of Gen 4 Paddles

Over the past 1 to 2 years, the word "foam" has been showing up on paddle spec sheets far more often. Foam cores are the construction at the heart of what are now called "Gen 4" (fourth-generation) paddles.

I'm Coach Yoshi. I've played tennis for 15 years and discovered pickleball in 2026. This article is a follow-up to What Is a Foam Core? (the beginner's guide). Drawing on sources from outside Japan, I'll dig into why foam cores came about, what they're made of, and how they relate to PBCoR, the standard for paddle rebound.

First, a Key Point: Paddle "Generations" Are Not an Official Standard

Before we get into it, just one thing. Pickleball paddles are often talked about in generations, like "Gen 1" or "Gen 4." But this isn't an official standard. These are labels that manufacturers and review sites started using each time core construction changed. USA Pickleball (the governing body in the U.S.) also breaks this history into generations in a June 2026 article, but when it comes to Gen 4, it describes it as "what many consider Generation 4."

Where the lines fall varies a little from source to source. Here's the general progression.

Some sources treat a foam perimeter as a feature of Gen 2 (The Kitchen), while others treat it as a feature of Gen 3 (USA Pickleball). In 2026, some sellers also started calling paddles that combine several kinds of foam "Gen 5," but there's no fixed definition for that either.

One thing you can say is that with each generation, foam has come to play a bigger role inside the core. Foam cores are the construction at the very front of that trend.

The Past: Why Foam Cores Came About, and the Side Effects of Thermoforming

The story starts with Gen 2 and thermoforming. This method uses heat and pressure to mold the face, core and edge into a single piece, and it spread from around 2022 to 2023. USA Pickleball explains that it increased power and durability. Thermoforming is often discussed together with raw carbon faces, but the face material and the core construction are separate topics. For raw carbon faces, see the Raw Carbon material guide.

However, this construction came with side effects. According to PickleballCentral, there are 3 main ways a paddle breaks down on the inside.

Delamination (layers separating): The layers that make up the face come apart from each other
The face-to-core bond failing: The bond that attaches the face to the core comes apart
Core crush: With repeated hits, the honeycomb core gradually collapses

The tricky part is that, depending on how it breaks down, a paddle can get more powerful the more you use it. The trampoline effect, where the face flexes and springs back, gets stronger, and the ball comes off faster than when the paddle was new. A paddle in this state is called a "hot" paddle, and it falls outside USA Pickleball's standards. It can also go the other way, with the rebound dying and leaving a "dead spot." I've covered the signs that it's time for a new paddle in Paddle Lifespan and Care.

💡 Coach Yoshi's Tip Sources differ on why paddles get "hot." Selkirk explains that delamination creates a trampoline effect. PickleballCentral says the idea that delamination is the cause is now considered unlikely, and that core crush is the leading theory. A USA Pickleball official has also said that paddles get hot when the core has been worn down through use. I think it's best to take any article that pins it on a single cause with a grain of salt.

That's where the idea came in of dropping the hollow-celled honeycomb and building the core out of foam instead. With no hollow cells to collapse, core crush is less likely. That was the starting point for foam cores. That said, the face layers and the bond between the face and the core can come apart in any paddle, whatever its construction.

Materials: What Foam Cores Are Made Of (EPP, MPP and EVA)

"Foam" covers several different materials. These 3 are the ones you'll hear about most often.

EPP (expanded polypropylene): A foam made by expanding small beads with heat inside a mold so they fuse together. Its density can be adjusted by the amount of beads. It's said to be the material most widely used today for all-foam cores (Pickleball.com). It's often described as having a softer feel that absorbs vibration and as being forgiving on off-center hits.
MPP (microcellular polypropylene): A foam made by injecting gas into polypropylene to create tiny air bubbles within a single solid piece (Pickleball.com). Opinions on how it feels are split. Some describe it as "denser and more rigid" and "more poppy" than EPP (The Dink), while others say it compresses more than EPP and has a more muted response (Pickleball Effect, Pickleball.com).
EVA (ethylene-vinyl acetate): A soft, very bouncy foam. A core made of EVA alone would be too bouncy, so today it's generally used for things like a ring around the outer edge of the core (Pickleball.com). Selkirk's Boomstik and Engage's X2 wrap EVA around a foam center, under the names "EVA Power Ring" and "EVA Foam Transition Ring," respectively.

There are a few other ways to use foam as well: adding foam layers to a honeycomb core so the center "floats" (a floating core), or layering another foam ring around a foam center. Selkirk's OMNI layers a PureFoam ring and an EVA ring around a PureFoam center. The goal is the same in every case: to deliver pop while keeping the response consistent wherever you hit on the face.

Some brands have taken a different path from honeycomb altogether. Gearbox has long been known for its own construction, SST (Solid Span Technology), which builds the core from carbon fiber ribs (a framework) instead of honeycomb. Its Pressure X, released in fall 2026, fills the space around the SST framework with either EPP or MPP foam. In its review, Pickleball.com writes that the MPP model, even though MPP is usually considered softer than EPP, ends up with the stiffer feel because of a difference in how the perimeter presses in on the core, and that the construction matters more to the feel than the type of foam. It seems fair to say the competition has shifted from whether to use foam to how to combine it.

💡 Coach Yoshi's Tip Even when a paddle says "foam core," the feel can vary a lot depending on which foam is used, where, and at what density. Selkirk has a model with cutouts in the perimeter of its foam core to change how it flexes, and Engage's X2 builds its core from foam in 4 different densities. The trick is not to judge the feel from the single word "foam" on a spec sheet.

Strengths and Weaknesses: What Foam Cores Do Well, and What to Watch Out For

Strengths

These are the 4 strengths most often cited for foam cores.

A large sweet spot and a consistent response: The response tends to be consistent wherever you hit on the face, with fewer dead spots (The Kitchen).
Cores resist crushing, so performance tends to last: With no hollow cells to collapse, core crush is less likely. EPP cores are said to have proven durable in real play so far, but long-term data is still limited (Pickleball Effect).
Less vibration and a calmer feel: EPP is described as absorbing vibration and having a softer feel. Foam cores are also said to sound quieter, but I couldn't find any measurements comparing their loudness with honeycomb in numbers. If you're worried about noise for your neighbors, choosing gear from USA Pickleball's Quiet Category, which I introduced in Pickleball Noise and How to Deal With It, is the more reliable option.
The ball stays on the face a little longer (dwell time): That's said to make it easier to adjust direction and spin. However, some take the view that differences in foam have only a small effect on spin (Pickleball.com).

Foam cores are valued not because they "hit the hardest," but because "their performance holds up over long use, and the response is consistent wherever you hit on the face."

Weaknesses

On the other hand, there are some points to watch out for.

The power can feel modest: Early all-foam paddles were described as lacking pop by players used to the strong rebound of Gen 3 paddles (The Kitchen, March 2025). Today there are power-oriented foam cores as well, so you can't say a paddle is weak just because it's foam.
Durability concerns with some materials: With some models that use MPP, concerns have been reported about the face separating from the core and about the core cracking in a brittle way. The cause isn't clear, and long-term data is still limited (Pickleball Effect).
Many models are on the expensive side: Foam cores spread from each brand's top-end models. In 2026, foam core paddles advertised at lower prices have also started to appear.
The single word "foam" doesn't tell you what's inside: Depending on the combination of material, density and layering, a paddle can lean toward power or toward control.

The Present: Foam Cores and PBCoR (the Rebound Limit and Testing at Tournaments)

Today, you can't talk about foam cores without talking about regulation. The key is a test called PBCoR. A ball is fired at about 60 mph (about 97 km/h), and the speed at which it bounces back off the paddle is used to put a number on the paddle's rebound (the strength of its trampoline effect). The higher the number, the bouncier the paddle.

The limit: USA Pickleball started at 0.44 in November 2024 and lowered it to 0.43 in November 2025 (still 0.43 as of October 2026). Each limit applies to paddles that undergo certification testing after its effective date
Existing models: Models that were already certified are also subject to testing. In December 2024, USA Pickleball announced that existing models exceeding the initial limit (0.44) could no longer be used in sanctioned tournaments from July 1, 2025
Testing at tournaments: In January 2026, a program began at some amateur tournaments (Golden Ticket events) to test competitors' paddles on site. It starts by checking things like face deflection and friction, with PBCoR and spin measurements to be added in the next phase (as of October 2026, I haven't found any announcement that they've been added). By March, more than 2,000 paddles had been tested, and about 6% failed to meet the standards. The most common reason was that the paddle had broken down

This test came about because rebound rose sharply with thermoformed paddles and with Gen 3 paddles, which added foam to honeycomb. All-foam Gen 4 paddles spread after that, and manufacturers are now competing over "how much rebound and feel they can build in while staying within the limit." For the details of how the test works and the story of the models that lost their certification, see What Is PBCoR? The Paddle Power Limit and How It's Tested. For how certification works, see USAP vs. UPA-A Certification.

The Future: Where Are Foam Cores Headed?

Finally, here's my own take on what comes next.

Foam cores will no longer be just for top-end models: In 2026, foam core paddles advertised at prices well below those of top-end models have appeared. I think this trend will continue.
Competition over how to combine foams: Layering foams of different densities, wrapping a ring around the perimeter, filling the space around a carbon fiber framework with foam. Brands are already putting out all kinds of constructions, and the differences will come down to "which foam is used, where, and how."
Spin: toward measuring the spin rate itself: Until now, USA Pickleball has kept spin in check with upper limits on surface roughness and the coefficient of friction. From October 1, 2026, it directly measures the spin rate of paddles newly applying for certification and limits it to 2,100 RPM (2,100 revolutions per minute) or less. I've covered how face materials relate to spin in Raw Carbon Grit and the Science of Spin.
The power story doesn't end with the limit: PBCoR measures rebound when the ball hits the paddle under fixed conditions; it isn't the ball speed of a full swing itself. There are also measurements showing that, even after PBCoR was introduced, full-swing ball speeds with certified paddles have kept rising with each release year (Pickleball Effect). The cat-and-mouse game between manufacturers and regulators looks set to continue.

As I see it, foam cores are no longer a new technology; they're the standard going forward. But now that they're the standard, it will get harder to say a paddle is good "because it has a foam core."

Summary: Foam Cores Are the Heart of Gen 4, but What's Inside Varies

Paddle "generations" are not an official standard, and where the lines fall differs by source. Even so, USA Pickleball's article and review sites outside Japan agree in using "Gen 4" for "a core made entirely of foam"
Foam cores spread against the backdrop of core crush and "hot" paddles in thermoformed and Gen 3 paddles
EPP, MPP and EVA each have a different character. Don't judge the feel from the single word "foam"
PBCoR caps rebound at 0.43. If you'll use a paddle in tournaments, check that the model is on the USA Pickleball or UPA-A approved list
Going forward, expect continued competition over how to combine foams, along with adjusting to new regulations such as the spin limit

If you want to start from the basics, read What Is a Foam Core? (the beginner's guide). For how power and control break down, see Control vs. Power Paddles, and for how the brands differ, see A Complete Comparison of the Major Brands.

The paddles we carry include foam core models, too. Engage's X2 (we're Japan's exclusive authorized distributor for Engage) has a core made of foam in 4 densities, which Engage bills as "100% Foam." Six Zero's Black Opal 14mm (we're an authorized dealer) uses the "G4 Aerospace Solid Foam Core." Selkirk's Boomstik and OMNI (we're an authorized dealer) wrap an EVA ring around a PureFoam center, and the SLK Dauntless has a one-piece PureFoam core. Knowing what's inside your gear makes choosing a paddle even more fun.

If you have questions like "Which foam core suits the way I play?" or "Is it about time to replace my current paddle?", feel free to ask me (Coach Yoshi) on LINE. You can add us as a friend through Pickleball Lab's official LINE account. You can also add us with the green "LINE Official" button at the bottom right of the screen.

References

Author

Coach Yoshi / Owner of Pickleball Lab

Former international ski competitor and active tennis coach. Discovered pickleball in LA in 2026 and has play-tested more than 100 paddles from Japan and around the world. Pickleball Lab is Japan's exclusive authorized distributor of Engage Pickleball (as of May 2026).

About Coach Yoshi →