I don't know if it happens to you too, but it seems like all the new running shoes releases we see now have one thing in common: a considerably high midsole height compared to what we knew 4 or 5 years ago.
The turning point came with the launch of the first version of the Nike Vaporfly, a running shoe that incorporated a combination of a high quality foam and a carbon plate. It was with this model that Nike demonstrated to the market that a higher sole height could significantly improve performance. True, the Vaporfly offered excellent cushioning, but it also provided an energy return that had not been seen before (where the plate had a lot to do with, admittedly), allowing runners to maintain a faster pace for longer.
The success of the Vaporfly led other brands to follow suit. Adidas, for example, later joined the trend, but did so in an even exaggerated way with the Adizero Prime X with a 50 mm heel height. And although World Athletics regulations limit the sole height to 40 mm for official competitions, training shoes and some competition models we are seeing continue in this vein.
The origin of premium foams
In order to better understand why high midsole heights have become fashionable, we must first analyze the origin and evolution of foams to what we now call super foams or premium foams. Foams have always been a fundamental component of running shoes, providing cushioning, reactivity and support. However, not all foams are the same.
Historically, EVA (ethylene-vinyl acetate) has been the most commonly used foam due to its durability and good cushioning capabilities. However, the limitations of EVA in terms of mainly energy return and light weight led the industry to look for more advanced alternatives. This is where super foams or premium foams come into play.
Types of premium foams
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Go to the Shoe FinderPremium foams, such as PEBA (Polyether block amide), Pebax (this is a variety of PEBA that was developed by the French chemical company Arkema) or TPEE (thermoplastic polyester elastomer), have become the market standard for high-performance running shoes. These foams offer significantly higher energy return and superior lightness compared to traditional EVA. But what makes these foams so special?
PEBA, for example, is a thermoplastic elastomer that combines flexibility, elasticity and strength. This structure allows the foam to be extremely lightweight and reactive, providing a higher energy return than EVA with each stride. However, it is true that its manufacture is more complex and above all more expensive than that of conventional EVA foams.
What do we consider a premium foam or a super foam?
When we talk about premium foam or super foam, we are referring to the latest generation materials used in the midsole of running shoes, which offer superior performance in terms of cushioning, energy return and lightness. These foams are designed to provide not only greater lightness and reactivity, but also to reduce fatigue and increase the runner's efficiency.
- Increased energy return
Premium foams offer significantly higher energy return than standard foams, typically between 80% and 95%. This high level of energy return helps runners maintain a faster pace and reduce muscle fatigue.
- Increased cushioning
These foams are designed to provide optimal cushioning, absorbing shock and protecting joints and muscles during running. This allows for a more comfortable run and reduces the risk of injury.
- Lighter weight
Premium foams are remarkably lightweight, which contributes to reducing the overall weight of the shoe. This is crucial for runners looking to maximize their performance, especially on long, high-intensity runs.
- Innovation in materials
Premium foams are typically made from advanced materials such as PEBA (Polyamide-block-ether), TPU (Thermoplastic Polyurethane) and other proprietary formulations that combine different polymers to achieve the desired characteristics. These materials are the result of scientific research and advances in materials technology.
- What about durability?
At the moment most premium foams appear to have inferior durability to EVA foams. Except for TPEE (used by adidas in the Adidas Adizero Adios Pro range). Durability may vary anyway, but the market is moving towards foams that are designed to withstand wear and tear while trying to minimize the loss of their cushioning and energy return properties.
The hardness of foams
The hardness of foams is a very important factor that affects both the comfort and performance of the shoes. Firmer foams, such as some variants of PEBA, or TPEE, offer greater stability and are more suitable for runners who need additional support and a greater quest for reactivity. On the other hand we have the softer foams that will provide a more comfortable feeling and shock absorption, being preferred for long distances. We do lose some stability and reactivity (hence the importance of carbon plates in the faster models, as the plate offers dynamism and control).
Each runner has different needs and preferences. Firm foams can be beneficial for those looking for fast response and more efficient energy transfer. On the other hand, softer foams may be more suitable for runners who prioritize comfort and cushioning.
The impact of foams on performance and race paces.
Higher midsoles with these types of super foams can have a significant impact on performance and race paces. A higher midsole provides more cushioning material between the foot and the ground, which will help reduce muscle fatigue and improve running efficiency, especially over longer distances.
This extra cushioning helps us to absorb impacts better, allowing runners to maintain a steady pace for longer periods of time.
But it is also true that greater height can also compromise stability. It is very important when looking for a shoe of this type to find a balance between cushioning and stability to optimize our performance. And that's where the brands' goal is to find a foam that balances cushioning, reactivity, lightness, durability and support. Complicated, isn't it?
The best foams of each brand
Each running shoes brand has its own premium foam formulation, optimized for different types of runners and their different needs. I'm going to introduce you to some of the best foams from each brand:
- Nike: ZoomX (Pebax) - Offers exceptional energy return and is used in high-end models like the Vaporfly and Alphafly.
- Adidas: Lightstrike Pro (TPEE) - Noted for its good durability and responsiveness, present in the Adizero line.
- Fuelcell (Pebax): Probably the foam that best combines softness and reactivity. It is also somewhat heavier.
- ASICS: FlyteFoam Blast Turbo (PEBA) - Provides a perfect balance between rebound and lightness, used in the Metaspeed series.
- Saucony: PWRRUN PB (Pebax) - Noted for its comfort and energy return, used in the Endorphin Pro line.
- Puma: Nitro Elite (PEBA + EVA) - Combines durability with reactivity, ideal for intensive training.
But more volume or more height is not always better.
We've already seen the benefits that can come from having running shoes with a high midsole. But more volume or height is not always synonymous with better performance. As I mentioned earlier, an excessively high midsole can compromise stability and increase the risk of injury, especially on uneven terrain or on runs with curves or changes of direction.
It is very important to consider your own needs and running styles when choosing shoes with higher midsoles. For example, we don't see much point in using this type of shoe for competitive exams where there are agility circuits.
In addition, a higher midsole can add unnecessary weight to the shoes. Although premium foams are lightweight, the additional bulk can make the shoes heavier, affecting speed and efficiency on shorter distance runs.
Durability of different types of foam
The durability of these types of foams is another key factor to consider. Premium foams, to date, have not proven to be as durable as traditional EVA foams. For example, those of you who have been users of shoes like the Nike Vaporfly with its ZoomX foam have sent us your opinion about the poor durability of the model300500 kilometers). After this period, we noticed a decrease in responsiveness and cushioning. At the moment, it happens with many of the marathon super shoes that usepremium foams.
On the other hand, TPEE-based foams, such as Adidas' Lightstrike Pro, have proven to be more durable, although it is true that their feel is not as soft, and they are harder on the run. These foams can deliver consistent performance up to 700-1,000 kilometers, depending on usage and running conditions.
Factors affecting durability
Heavy use: Premium foams can wear more quickly with heavy use and on hard surfaces. High mileage runners should consider durability as a key factor when selecting their shoes.
Runner weight: Heavier runners may experience greater foam compression, reducing the life of the foam. It is important for runners to choose foams that match their weight and running style.
Weather conditions: Extreme temperatures can affect the elasticity and durability of foams. Foams can become stiffer in cold weather and lose their shock absorption capacity, while in hot weather they can degrade faster.
It is very important to balance the need for high performance with the durability of your shoes.
Top models with quality super foams
- Nike Alphafly 3
The Nike Alphafly 3 is equipped with ZoomX foam. This is a PEBA (Polyether Block Amide) based foam, known for its exceptional energy return and light weight.
- ASICS Metaspeed Sky Paris
The ASICS Metaspeed Sky Paris uses FlyteFoam Blast Turbo foam, which is composed primarily of Nylon / PEBA. This combination provides excellent rebound and durability.
- adidas Adizero Adios Pro 3
The adidas Adizero Adios Pro 3 features Lightstrike Pro foam, made from TPEE (Thermoplastic Polyester Elastomer), which gives it impressive durability and consistent energy return.
- Saucony Endorphin Pro 4
The Saucony Endorphin Pro 4 uses PWRRUN PB foam, which is composed of PEBA. This foam is known for its combination of softness and energy return.
- New Balance FuelCell SuperComp Elite v4
The New Balance FuelCell SuperComp Elite v4 is equipped with FuelCell foam, which uses a blend of PEBA. This formulation offers maximum cushioning and excellent energy return.
- Hoka Cielo X1
Incorporates a highly reactive PEBA foam. This foam does not yet have a commercial name, but provides an optimal balance between cushioning and energy return, capable of making the difference in these HOKA Cielo X1
- PUMA Fast-R Nitro Elite 2
The PUMA Fast-R Nitro Elite 2 uses Nitro Elite foam, composed of PEBA and A-TPU (aliphatic TPU). This formulation offers impressive energy return and enhanced durability.
- On Cloudboom Echo 3
The On Cloudboom Echo 3 is equipped with Helion HF foam, based on PEBA. This foam offers excellent energy return and reactivity.
- Brooks Hyperion Elite 4
The Brooks Hyperion Elite 4 with its updated nitrogen-infused DNA FLASH v2 foam featuring a new formulation that is lighter than the previous version (nitrogen-infused EVA). This combination provides increased reactivity and very good durability.
- Mizuno Wave Rebellion Pro 2
The Mizuno Wave Rebellion Pro 2 features Enerzy Lite+ foam, which is a PEBA-based formulation. This foam provides a soft and responsive underfoot.
And then... How does midsole height in a running shoe affect running performance?
You have to stick with this idea: The height of the midsole significantly affects a runner's performance. But of course it's not the only quality that makes a difference: The amount of cushioning and support a shoe can offer, as well as its stability and the runner's efficiency are also decisive. But how does a higher or lower midsole height affect our performance?
- Cushioning and comfort
High midsole: shoes with a higher midsole usually offer more cushioning, which can provide a comfortable and soft feel during the run. This extra cushioning can be beneficial for long runs, as it reduces impact on joints and muscles, reducing fatigue.
Low midsole: A lower midsole offers less cushioning, which can result in a firmer, less comfortable feel, especially on long runs. However, some runners prefer thismore direct and closer-to-the-ground feel, as it provides greater feedback from the ground.
- Energy return
High midsole: A higher midsole height allows for the inclusion of advanced foams and other technologies that increase energy return. This can help runners maintain a faster pace with less effort, as the shoe returns some of the energy applied in each stride.
Low midsole: Although it may have a lower energy return, some advanced foams can provide good energy efficiency even in shoes with a lower midsole. These shoes tend to be lighter, which can be advantageous for shorter distance runs and sprints.
- Stability and control
High midsole: Increasing midsole height can compromise the stability of the shoe, especially for runners with pronation problems or on uneven terrain. The increased height can make the foot more prone to unwanted lateral movement, increasing the risk of twisting or injury.
Low midsole: Offers greater stability and control, as the foot is closer to the ground. This is ideal for runners seeking a greater sense of security and stability, especially on technical runs or uneven terrain.
- shoe weight
High midsole: Generally, a higher midsole height means more material, which can increase the overall weight of the shoe (although we have already seen that foams are now much lighter). More weight can negatively affect performance, especially in long distance races where every gram counts.
Low midsole: These shoes are usually lighter, which can improve the runner's speed and efficiency. Short distance runners and those looking to maximize their speed can benefit from a lighter weight.
- Drop (difference in height between heel and toe)
HighDrop: A higher drop can help if you tend to land with your heel, providing more cushioning in this area and promoting a smooth transition into the forefoot.
LowDrop: A low or zero drop promotes a more natural stride and a more efficient posture. It is preferred by runners who land with the forefoot or midfoot and those seeking a more minimalist running technique.
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