Issue four of Sportstextiles magazine is here, exploring, as always, the frontiers of performance and sustainability in materials for outdoor and sports clothing, footwear and equipment. Biotech dyes are taking off, offering a lower-impact alternative to conventional colourants, while Polartec’s new AirCore fabric promises breathability and moisture control for cyclists and beyond, without PFAS materials. In Newcomers, Hyosung and Loop Industries show how textile-to-textile recycled polyester can go mainstream, bringing circularity to everyday garments. Sustainability highlights the latest in biobased elastane, recycled insulation, protein-derived fibres and other innovations at the recent Future Fabrics Expo in London, plus the argument that regulations can be the ‘stick’ required to help these materials reach scale. Our Dialogue rounds out the issue with Haglöfs’ chief executive, Martin Daniels, reflecting on PFAS-free outerwear, product durability as the path to circularity, and the brand’s ambitious growth across Asia. We hope you enjoy every article.