SLICE is a footwear concept by designer Soroosh Riazi Isfahani that repurposes used tennis balls by cutting and reshaping them into shoe components rather than shredding or melting the material. Entered into the James Dyson Award 2026, the project uses a custom cutting guide to preserve the tennis ball's original rubber structure and felt surface, allowing the material's existing properties to remain intact throughout the manufacturing process.
The concept evolved from earlier experiments that combined shredded tennis balls with natural rubber for outsole production before shifting to a process that retains the material's layered construction. By avoiding energy-intensive recycling methods, the approach minimizes additional processing while making use of the durability, resilience and textured felt already present in discarded tennis balls. . Developed through research at the Royal College of Art and Imperial College London, the project explores an alternative upcycling strategy for a sporting product that is rarely recycled after use.
Upcycled Tennis Footwear
SLICE Transforms Used Tennis Balls into Wearable Shoes
Trend Themes
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Low-intervention Upcycling — Preserving existing material structures creates room for circular products that reduce processing energy while maintaining performance characteristics.
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Sports Waste Footwear — Discarded athletic equipment is emerging as a source of durable components for fashion products with built-in sustainability narratives.
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Material-first Design — Design concepts centered on the original properties of waste materials can produce distinctive forms that differ from conventional recycled goods.
Industry Implications
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Footwear — Shoe brands can differentiate through visible upcycled components that combine functional texture, resilience and environmental value.
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Sporting Goods — End-of-life sports products present new revenue pathways when their specialized materials are redirected into adjacent consumer categories.
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Sustainable Fashion — Circular design methods that avoid shredding or melting support lower-impact production models with stronger traceability and storytelling potential.