Global initiative Fashion for Good has unveiled a 12-month project to explore sustainable and circular alternatives for shoe soles.

The Next Stride: Bio-Based Materials for Footwear Soles project will involve testing and validation of bio-based polymers as an alternative to traditional fossil fuel–derived materials.

The project brings together key industry players, including adidas, Target, and Zalando, alongside material innovators such as Algenesis Labs, Balena, Evoco, KUORI, and Yulex.

Soles constitute approximately 40% of a shoe’s total mass and are predominantly made from non-recyclable fossil fuel–based polymers like PU, TPU, EVA, and rubber.

A standard synthetic running shoe is estimated to have a carbon footprint of approximately 14 kilograms of CO2, and 97% of this environmental impact can be attributed to the processing and manufacturing of raw materials.

Fashion for Good managing director Katrin Ley 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.”

‘The Next Stride’ project is set to undertake a comprehensive evaluation process that encompasses material assessments, performance mapping, and extensive testing.

Initially, the project will conduct an in-depth analysis of the innovators’ bio-based materials to ensure they meet the performance standards required by partner companies.

Following the validation phase, prototypes will undergo testing in collaboration with SATRA, an independent research and testing organisation, to confirm their performance capabilities and environmental benefits compared to traditional options.

The outcomes of these tests are expected to contribute to the creation of a roadmap that will guide larger-scale adoption of bio-based soles across the industry.

“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,” adidas sustainability direction director Gudrun Messias said.