In the sports industry, the products currently being developed by design teams are degraded over time due to wear and tear. During the last decade, awareness about the global environmental crisis has increased and sports users are now more demanding about the environmental impact of products and services that they are using. Therefore, people are searching for companies that make durable and sustainable products and services. While the importance of durability regarding the development of a circular economy has been recognized, a concrete concept has not yet been specifically addressed in European product policies. Standards are missing and this research aims to develop a method, where companies from the water-sports industry could follow a step-by-step process to assess the normative lifespan of a product, especially in the early design stages of the product development process.

The case study of OLAIAN, the DECATHLON surf brand, has made it possible to develop repeatable long-term quality test protocols on neoprene wetsuits and surfboards to characterize the ageing of these products. A product’s resistance is one of the durability factors that are tested in this method, by creating a database containing the number of uses a product has made and its evolution over time. This case study has allowed the testing of different protocols in co- creation with the surf organizations and explores further the study of a testing phase during the product development process.

From these empirical findings, a 10-step method has been designed to estimate the normative lifespan of a product. Globally, the outcomes are intended for the design team, in order to know a product’s resistance over time and its weaknesses, thus being able to improve and further its lifespan. A second outcome is to fulfill information to complete studies on durability. Therefore, increase the reliability of Life Cycle Analysis and observe where is the biggest environmental impact in the product’s process (from inception to recycling) to take actions. This also helps to know more precisely the temporal warranty that companies can promise to their customers, and it completes studies on environmental indicators display to guide consumers to more sustainable choices.

This study aims to allow in the future, sports organizations certified by Standardization organization for testing of products and the assessment of their durability. Further research on sensors or electronic devices, to more precisely follow the evolution of product during field- testing would be very relevant. As this thesis focused on field-testing for the reliability of products, based on these results further research in statistical models to support failures analysis in accelerated lab-testing must be implemented. Another opportunity is the emergence of platforms and product-service systems in the sports field. This could open up opportunities to have products used at a high frequency and in intense conditions to enable faster feedback on durability.