A year-long project has been launched by Fashion for Good to develop bio-based alternatives for footwear soles. The Next Stride initiative will test bio-based polymers as replacements for fossil fuel–derived sole materials. Prototypes will be assessed with SATRA, an independent testing organisation, for durability and environmental impact against conventional sole components.
- The project was announced in Amsterdam on Thursday as a year-long effort to drive sustainable solutions in footwear soles.
- Project partners include Adidas, Target and Zalando, alongside material innovators Algenesis Labs, Balena, Evoco, Kuori and Yulex.
- Soles are a crucial driver of a product's overall footprint, with at least a 40% share of the total mass of the shoe.
- A typical synthetic running shoe has a carbon footprint of around 14 kg of CO2, with 97% of this impact traced to raw material processing and manufacturing.
THE LAUNCH STRATEGY: The announcement of The Next Stride has signalled a decisive intervention at a time when footwear sustainability is under mounting scrutiny. By formally unveiling the project, Fashion for Good has established a clear agenda to challenge the dominance of fossil fuel–derived sole materials. The launch has underscored urgency in redirecting resources towards circular alternatives and has demonstrated leadership in uniting diverse stakeholders under one collaborative programme.
- The launch has been timed to frame footwear sustainability as an immediate industry challenge requiring collaborative interventions rather than distant future commitments.
- The announcement has provided a structured framework, giving the industry a tangible benchmark against which progress and accountability can now be measured.
- The launch has highlighted footwear soles as the priority intervention point, distinguishing the project from initiatives that often spread focus across multiple apparel components.
WHY SOLES ARE THE PRIORITY: Footwear soles have remained one of the most intractable sustainability problems, given their reliance on fossil fuel–derived polymers and limited recyclability. With soles representing the largest share of a shoe’s mass and driving most of its environmental footprint, stakeholders face mounting pressure to address carbon emissions, microplastic release, and the absence of scalable circular solutions across the global footwear supply chain.
- Soles account for more than 40% of footwear weight, making them the single biggest driver of lifecycle environmental impact across the sector.
- Besides, soles are also a source of fibre fragmentation: abrasion from synthetic materials such as footwear soles contributes significantly to primary "microplastics" released into the environment, with studies showing these fragments and additives accumulate in soils, waterways, and even indoor air.
THE EVIDENCE FOR CHANGE: Research has documented the scale of footwear’s footprint, underscoring why the sole is a critical intervention point. A typical synthetic running shoe carries substantial carbon emissions, and material processing dominates that impact. Beyond emissions, microplastic shedding from soles has been identified as a persistent pollutant, confirming the need for validated alternatives that perform at scale without repeating the environmental harms of existing polymers.
- Roughly 97% of that footprint has been traced to raw material processing and manufacturing, reinforcing the significance of upstream interventions.
- Scientific studies have confirmed that abrasion from synthetic soles releases microplastic particles that accumulate in soil, water systems, and indoor environments.
BEYOND A NICHE SOLUTION: The footwear industry has long struggled to align sustainability goals with scalable material innovations, leaving most solutions limited to niche products or pilot programmes. The Next Stride has positioned itself within this wider transformation effort, aiming to shift an industry valued at $400 billion. By targeting the sole, the initiative directly connects with broader systemic moves towards circularity and decarbonisation across global fashion supply chains.
- Circularity has remained elusive because conventional sole materials such as PU, TPU, EVA, and rubber have limited recycling options.
THE PARTNERSHIP MODEL: Fashion for Good has brought together an unusual coalition of global brands and innovators, moving beyond isolated experiments towards structured collaboration. Collectively, they have agreed to test and validate bio-based polymers, aligning commercial requirements with environmental performance benchmarks to accelerate the search for scalable alternatives to fossil-based soles.
- The project begins with a deep validation of the innovators' material offerings and the alignment of these with partner performance requirements. Prototypes will then be tested in collaboration with SATRA to validate both performance and environmental impact against conventional options. The findings will then be used to inform the development of a roadmap for larger-scale adoption.
FROM LAB TO MARKET: The Next Stride has set out a roadmap for the months ahead, focusing on structured testing phases and industry engagement. Findings will inform adoption pathways, including infrastructure needs, feedstock availability, and end-of-use solutions, providing stakeholders with practical insights into scaling bio-based soles across global markets.
- Results will guide development of a roadmap for larger adoption, incorporating practical considerations such as infrastructure readiness and supply chain integration.
- Stakeholders will receive clearer benchmarks for scaling bio-based solutions, helping brands plan investments and operational adjustments over the coming year.
WHAT THEY SAID
The Next Stride is a critical, collaborative intervention to de-risk the widespread adoption of high-performance bio-based alternatives for footwear soles. By transforming the very foundation of the shoe, we address the most impactful component in its lifecycle and open the door to systemic change in the footwear industry.
— Katrin Ley
Managing Director
Fashion for Good
For adidas, sustainability and performance go hand in hand. Through The Next Stride, we will work with innovators to explore if bio-based materials can potentially lower the environmental impact of footwear soles while at the same time meeting or even enhancing the high-performance standards our athletes and consumers expect from adidas products.
— Gudrun Messias
Director, Sustainability Direction
Adidas
As we have recently confirmed in our sustainability attitude-behaviour gap report, It Takes Many, consumers aspire for more sustainable choices. We believe innovation in materials is key to meeting that demand. The Next Stride brings together the right partners to reimagine the sole, the foundation of every shoe, and set new benchmarks for the industry.
— Pascal Brun
VP Sustainability and D&I
Zalando
