Which Racket Foams Are Most Likely to Last?
FLO Lab | Research Review
A padel-racket core needs to recover after thousands of ball strikes.
A lively first bounce tells us something about how a foam performs when new.
Durability asks a different question:
How much of that response remains after repeated use?
FLO has reviewed four candidate foam grades:
- PN28 — 27 kg/m³
- EV30 — 30 kg/m³
- EV50 — 50 kg/m³
- VA35 — 35 kg/m³
Using the supplied material-properties sheet alongside published EVA fatigue research, EV50 is currently the strongest candidate to test first for durability.
Our provisional screening order is:
- EV50
- VA35
- EV30
- PN28
This is not a verified ranking of padel-racket lifespan.
It is an order based primarily on resistance to permanent compression in the supplied sheet, supported by its reported tensile and tear properties.
The difference matters.
What Do We Mean by “Last”?
A foam can last in several different senses.
It may resist permanent compression.
It may preserve rebound.
It may retain its stiffness.
It may resist tearing.
It may recover quickly between impacts.
It may remain consistent across hot and cool playing conditions.
A grade that performs well in one area may not lead in every other area.
For a padel racket, the most useful definition would be:
The foam continues producing an acceptably consistent response after repeated impacts inside the finished racket construction.
The supplied sheet cannot establish that by itself.
It can only help identify which materials deserve priority in testing.
What Research Outside FLO Tells Us
Published research helps explain why EVA changes under repeated compression.
Aimar and colleagues subjected closed-cell EVA foam to cyclic compression and examined its internal structure using X-ray microtomography.
They observed cell flattening, permanent bending and increased tears or holes in cell walls. Interrupting the cycling allowed partial recovery, but it did not erase the fatigue mechanisms that had developed.
The study helps demonstrate that foam fatigue is not simply a temporary reduction in bounce. Repeated loading can change the internal cellular structure itself.
However, the tested material was associated with running-shoe applications—not padel-racket cores.
It explains a mechanism.
It does not provide a racket lifespan.
Formulation Matters Alongside Density
Wen and colleagues studied microcellular EVA under reciprocating compression and developed a fatigue-life model.
The research examined foams with densities considerably higher than the four grades in FLO’s supplied sheet. That prevents direct numerical comparison with PN28, EV30, EV50 or VA35.
Its broader lesson remains useful:
Density alone does not describe fatigue performance.
Gel content, cellular structure and formulation influenced the material’s mechanical behaviour under cycling.
Two foams carrying similar density or hardness descriptions can therefore behave differently because the material behind those numbers is different.
Stiffer Does Not Automatically Mean More Durable
A 2026 study investigated how biosourced silica nanofiller content affected the fatigue and recovery of EVA-based cellular composites.
Increasing reinforcement changed mechanical properties, cell-wall behaviour, accumulated deformation and shape recovery.
The researchers identified a trade-off between reinforcement and fatigue durability.
That is important for racket development.
A foam may feel firmer when new.
It may produce higher initial test values.
Neither observation automatically proves that it will preserve its performance for longer.
The complete formulation still matters.
What These Studies Do Not Tell Us
These are external materials studies, not FLO racket tests.
They do not establish:
- How many padel hits a foam will survive
- How many months a racket will remain lively
- Which of the four supplied grades will retain rebound longest
- How the foam behaves after being combined with carbon, resin and frame construction
- How temperature and real playing conditions affect each finished racket
- Whether one player will fatigue a core faster than another
The Aimar study includes university and Decathlon affiliations, but it remains research into EVA fatigue rather than proof about a commercial padel core.
None of the three papers tests the exact PN28, EV30, EV50 and VA35 grades listed in the supplied sheet.
Their value is in helping us understand what to examine.
They do not give us a ready-made lifespan table.
What the Supplied Sheet Shows
The supplied properties sheet reports compression set after the foam was compressed by 25% for 22 hours at 23°C.
Compression set describes how much residual deformation remains after the load has been removed and the foam has been allowed to recover.
Lower is better within that particular test.
It does not measure ball rebound.
| Screening order | Grade | Density | After 30 minutes | After 24 hours |
|---|---|---|---|---|
| 1 | EV50 | 50 kg/m³ | 9% | 2% |
| 2 | VA35 | 35 kg/m³ | 10% | 3% |
| 3 | EV30 | 30 kg/m³ | 13% | 4% |
| 4 | PN28 | 27 kg/m³ | 15.2% | 8% |
The figures create a clear screening order for recovery from the stated static-compression test.
They do not establish the same order under repeated ball impacts.
EV50: The First Durability Candidate
EV50 records the lowest compression set:
- 9% after 30 minutes of recovery
- 2% after 24 hours
It also has the highest reported tensile strength and tear strength among the four grades on the supplied sheet.
Together, these properties make EV50 the strongest candidate for the first durability trial.
That does not mean EV50 has already won.
Its greater density may affect:
- Core mass
- Finished-racket weight
- Balance
- Feel
- Deformation
- Rebound
- Player comfort
A durable foam is only useful if the resulting racket still meets its intended playing specification.
VA35: A Lower-Density Challenger
VA35 follows closely on compression set:
- 10% after 30 minutes
- 3% after 24 hours
At 35 kg/m³, it is substantially less dense than EV50.
That makes it an important candidate where mass and recovery both matter.
If VA35 preserves rebound nearly as well as EV50 inside matched rackets while allowing a more suitable weight or balance, it may become the better material for certain constructions.
The most durable isolated sample is not automatically the best complete racket core.
EV30: The Softer Candidate
EV30 records:
- 13% after 30 minutes
- 4% after 24 hours
The supplied sheet also gives it the lowest Shore 00 hardness of the four grades.
That makes it relevant where a softer response is desired.
The key question is whether it can retain that response after repeated impacts.
A softer initial feel should not automatically be interpreted as poor durability. Equally, comfort when new should not be assumed to remain unchanged.
EV30 needs to be tested for both response and response retention.
PN28: Last in This Screening, Not Proven to Fail First
PN28 has the highest reported compression set:
- 15.2% after 30 minutes
- 8% after 24 hours
It therefore ranks last on this particular recovery measure.
That does not prove that PN28 will fail first in a finished padel racket.
The supplied sheet does not provide:
- Full polymer formulation
- Vinyl-acetate content
- Cell-size distribution
- Crosslink density
- Filler system
- Detailed processing history
- Independent certification
- Repeated-impact performance
The correct conclusion is narrow:
PN28 shows the greatest residual deformation in the supplied static-compression comparison.
Anything beyond that requires testing.
Why Density Cannot Decide the Winner
The provisional order broadly follows density, but that does not make density the cause of the result or a universal predictor.
Foam durability can also be influenced by:
- Polymer chemistry
- Vinyl-acetate content
- Crosslinking
- Cell size
- Cell-wall thickness
- Open- versus closed-cell content
- Filler type and quantity
- Foaming process
- Cure conditions
- Temperature
- Strain level
- Recovery time
A future supplier could provide another 35 kg/m³ foam that behaves completely differently from VA35.
The grade must be tested—not merely the density label.
What Would Confirm the Longest-Lasting Foam?
The next useful FLO Lab comparison should move from loose material data into matched finished rackets.
For each foam grade, FLO should produce several rackets with the same:
- Mould
- Face material
- Lay-up
- Resin system
- Hole pattern
- Frame construction
- Target weight
- Target balance
- Manufacturing process
Using multiple samples matters.
One racket from each grade would not separate material behaviour from normal manufacturing variation.
Each racket should be measured before fatigue testing, at predetermined impact intervals and after a standard recovery period.
The trial should control:
- Ball model and condition
- Impact speed
- Impact angle
- Impact location
- Racket support
- Temperature
- Humidity
- Recovery time
- Number and spacing of impacts
What Should Be Measured?
At minimum, FLO should record:
- Initial rebound response
- Rebound after agreed impact counts
- Recovery after resting
- Changes in sound
- Changes in face deflection
- Changes in racket mass and balance
- Visible or internal damage
- Player-blind feedback where practical
The most useful result will not necessarily be:
Which foam survived the highest number of cycles?
It may be:
Which foam retained the most suitable playing response for the longest period inside this particular racket construction?
That is the question the player actually cares about.
Shoe-Foam Cycles Are Not Padel Hits
Published cyclic-compression studies cannot be converted directly into a number of padel impacts or months of play.
The loading conditions are different.
A laboratory sample may be compressed uniformly between plates.
Inside a racket, the foam works within a composite structure and receives localised dynamic impacts through the face.
Ball strikes vary in:
- Speed
- Location
- Spin
- Angle
- Frequency
- Temperature
- Player technique
A statement such as “100,000 laboratory cycles equals a certain number of matches” would therefore be unsupported without a validated relationship between the two tests.
FLO should not make that claim.
The Current Recommendation
From the supplied properties sheet, our current screening recommendation is:
Test EV50 first.
Test VA35 alongside it as the lower-density challenger.
EV30 should remain in the trial where a softer core is required.
PN28 should not be rejected solely from one static-compression measure, but its higher compression set means it enters the trial with the weakest recovery case from the available sheet.
The final winner should not be the foam with the highest density, hardest initial feel or strongest marketing description.
It should be the foam that retains the required performance after repeated impacts inside a finished racket.
Supported by measurements.
Repeated across multiple samples.
And confirmed on the court.
The properties sheet gives us a shortlist.
FLO Lab still has to find the answer.
Sources
-
C. Aimar, L. Orgéas, S. Rolland du Roscoat, L. Bailly and D. Ferré Sentis, “Fatigue mechanisms of a closed cell elastomeric foam: A mechanical and microstructural study using ex situ X-ray microtomography,” Polymer Testing, Volume 128, 108194, 2023. https://doi.org/10.1016/j.polymertesting.2023.108194
-
S. Wen, Z. Xin, A. D. Phule and Z. X. Zhang, “Microcellular Ethylene–Vinyl Acetate Copolymer Foam: Life Prediction Under Reciprocating Compression,” Advanced Engineering Materials, Volume 24, 2101089, 2022. https://doi.org/10.1002/adem.202101089
-
“Effect of biosourced silica nanofiller content on deformation-induced cell morphology and compression fatigue of EVA-based cellular composites,” Composites Part C: Open Access, Volume 20, 100741, 2026. https://doi.org/10.1016/j.jcomc.2026.100741
-
Supplied document: EVA Properties(1).pdf. Source of the four-grade comparison. No authorship, test standard or independent certification is displayed on the sheet.
