In the textile and clothing sector, a wide range of auxetic textiles have been made and shown great application potential in many areas. Creating auxetic effect at the yarn stage is relatively a simple approach since helical auxetic yarns (HAY) can be made only by winding or twisting different conventional filaments together with existing spinning machinery. Employing sports safety equipment is a cost-effective solution for avoiding injury and increasing the safety and protection. In the area of materials development for sports safety equipment, an important candidate is auxetic materials. In this study, polyester filament/elastane based helical auxetic yarns (HAY) and knitted fabrics from the yarns were developed that will offer dampening effect against injuries during sports activities. Effects of count of the elastane component and the presence of a third component in the HAY structure on the auxetic behaviour of the knitted fabrics were also studied.