What Does Energy Return Really Mean?

Energy return refers to how efficiently a foam rebounds after being compressed, creating the responsive or “bouncy” feel many runners notice in modern performance footwear. Below, we’ll explain what energy return is, how it’s measured, what influences it, and why it has become such an important part of footwear design.

If you’ve been following the latest trends in performance footwear, you’ve probably heard the term “energy return.” It’s become one of the most talked-about characteristics in modern running shoes. But what does it actually mean, and why has it become such an important part of footwear design?

During this year’s Portland Track Festival, one thing stood out after talking with athletes: runners notice when their footwear feels responsive. They describe it as “springy, bouncy”, or simply feeling smoother with every stride. 

All of those feelings can be related back to one key material characteristic: energy return.  

What is Energy Return?

The answer is surprisingly simple. When your foot hits the ground the foam beneath your feet compresses or pushes down. As it rebounds, some of the energy from your step returns. The more efficiently a material rebounds, the more responsive it feels. That is where that bounce sensation comes from. 

Think of a foam like a spring. When compressed, it stores energy. As it returns to its original shape, some of that stored energy is released. The more efficiently the material rebounds, the more responsive it feels underfoot.

How is Energy Return Measured?

While “bounce” is easy to feel, engineers rely on standardized testing to evaluate energy return. One common method is the ASTM D2632 test, which measures a material’s resilience by evaluating how efficiently it rebounds after impact.

This is the same ASTM D2632 resiliency test we demonstrated at our booth earlier this year during The Materials Show, where visitors could see how different foam materials respond and rebound in real time.

These objective measurements allow material developers to compare foam formulations and optimize material properties for different applications. While laboratory testing provides valuable insights, real-world performance ultimately depends on how the material is integrated into the complete footwear system, including the shoe’s design, geometry, and intended use.

Energy Return Vs. Cushioning

Many people assume that softer automatically means better performance, but that isn’t necessarily the case. There is an important difference between soft cushioning and responsive cushioning, and each has a different purpose.

Responsive cushioning is designed to return a greater portion of the energy generated with each step than materials designed primarily for impact absorption. As the foam compresses under your foot, it rebounds, returning some of that energy and creating the “bounce” or responsive feel often associated with performance footwear.

Soft cushioning, on the other hand, is designed primarily for comfort. It absorbs and disperses impact to create a plush underfoot feel that helps reduce the forces experienced with each step, making it ideal for everyday comfort and long periods of wear.

Neither approach is inherently better than the other. High-quality responsive foams and soft cushioning materials both play an important role in enhancing the wearer’s experience. The best choice depends on the intended application and the needs of the individual, whether that’s maximizing responsiveness for performance or prioritizing comfort for everyday activities. The best footwear isn’t defined by the most cushioning or the highest energy return. It’s about engineering the right balance.

What Factors Influence Energy Return?

Several key factors influence the energy return you feel when you step into a high-performance shoe. While the sensation may feel simple, the material science behind it is carefully engineered.

Energy return is shaped by a combination of foam chemistry, cell structure consistency, density, material design, and manufacturing process. Each factor affects how the foam compresses under force, how quickly it rebounds, and how much of that energy is returned with each step.

At DSC®, our engineers and chemists work to tune these material properties based on the needs of each application. By adjusting the structure and performance characteristics of the foam, we help designers, developers, and engineers create footwear solutions with the right balance of cushioning, responsiveness, durability, and comfort for each project.

Why Supercritical Fluid Foaming Has Become So Popular

One of the technologies driving these improvements is Supercritical Fluid Foaming (SCF). As energy return has become one of the defining characteristics of modern performance footwear, SCF has become an increasingly important part of the conversation. While it is often associated with the responsive, “bouncy” feel found in today’s running shoes, its benefits extend well beyond energy return alone.

During the SCF foaming process, gases such as carbon dioxide (CO₂) or nitrogen are introduced in a supercritical state to create a highly consistent cellular structure. This level of control allows engineers to develop foams that can be engineered for lightweight, durable, and responsive performance.

The result is a material that compresses under impact and rebounds efficiently, creating the responsive feel many runners associate with today’s performance footwear. Just as importantly, SCF technology gives designers, developers, and engineers greater flexibility to tune material properties, helping them achieve the right balance of responsiveness, cushioning, durability, and weight for each application.

Why Energy Return Matters to Athletes

Athletes may never think about the chemistry or cellular structure inside their shoes, but they definitely notice how those materials perform. The right combination of responsiveness, cushioning, durability, and weight can contribute to a smoother ride, a more comfortable experience, and the confidence that comes from consistent performance in their footwear.

Events like the Portland Track Festival give us the opportunity to hear directly from athletes and better understand what matters most to them. Those conversations reinforce an important truth: no two applications require the same material solution. That’s why at DSC® we engineer foams with a range of performance characteristics, helping footwear brands create products tailored to the needs of the people who wear them.

Engineering the Right Balance

The next time someone talks about the “bounce” in a running shoe, you’ll know there’s much more happening beneath the surface. Behind every responsive step is years of material science, engineering, and innovation working together to create the right experience underfoot. The best materials are those engineered to deliver the right balance of responsiveness, cushioning, durability, weight, and comfort for their intended application.

At DSC®, we believe every great product begins with materials engineered around real-world needs. Whether it’s maximizing energy return for performance footwear or designing comfort for everyday wear, we’re continually exploring new ways to help brands take materials further.

Interested in learning more about DSC’s advanced foam technologies? Connect with our team to discover how we’re engineering the next generation of material solutions.

Frequently Asked Questions

What is energy return in footwear?

Energy return refers to how efficiently a foam rebounds after being compressed, returning a portion of the energy generated with each step and creating a more responsive feel.

Does more energy return mean a better shoe?

Not necessarily. The best footwear is engineered to provide the right balance of energy return, cushioning, durability, comfort, and weight for its intended application.

What is Supercritical Fluid (SCF) Foaming?

Supercritical Fluid Foaming is a manufacturing process that uses gases such as carbon dioxide or nitrogen in a supercritical state to create a highly consistent foam structure. This process gives engineers greater control over material properties.

How is energy return measured?

Engineers commonly use ASTM D2632 resiliency testing to evaluate how efficiently a foam rebounds after impact.

Why is energy return important?

Energy return contributes to the responsive feel of performance footwear, but it is only one factor among many that influence overall comfort and performance.