The rich research tapestry that foreshadowed advanced footwear technology and what it suggests for the future

Since the early 1980s, with the emergence of footwear biomechanics and the focus on performance in running shoe design and engineering, shoes have been thought of as having an ergogenic potential. However, the notion that footwear can have energetic penalties, or, conversely, benefits, first came to light in the 1940s, with reports on the outsized effects of shoe mass and mass distribution on the energetic cost of transport while walking (Russell & Belding, 1946). Catlin and Dressendorfer (1979) extended similar observations to running. This notion of lighter meaning faster, was quickly embellished by the idea that cushioning also might have an ergogenic benefit (Frederick et al., 1986). During this same period, McMahon and Greene (1978) demonstrated that running tracks tuned to runners’ mechanics could enhance performance. So we began to think that mechanically ‘tuning’ shoes might also provide ergogenic benefits. At that moment, the list of potential shoerelated ergogenic factors would have included: making shoes lighter, appropriately cushioned, and perhaps tuning their compliance to a runners’ lower limb mechanics. More than a decade later, Stefanyshyn and Nigg (2000) added another critically important idea to this general theory of shoe-generated ergogenic benefits. Their proposal that joint energy could be conserved or perhaps redirected by using stiff moderator plates to enhance performance and reduce overall energetic cost was quite radical at the time, and it foreshadowed the development of Advanced Footwear Technology (AFT). Impressive in its performance (Hoogkamer et al., 2018) the Nike Vaporfly 4% ushered in a new era of AFT in 2017. Researchers and developers at Nike exploited these fundamental concepts of ergonomic benefits in running shoes by incorporating lightweight, highly resilient cushioning materials and stiff moderator plates. These technologies were packaged in a unique geometry, specifically a shoe with a sizeable stack height and pronounced forefoot rocker, to help maximise the effects as well as alleviate some potential negative side-effects that can arise from some of these technologies (Farina et al., 2019). Interestingly, the 4% improvement in running economy with the Vaporfly shoes aligns well with a cumulative result of published effects associated with each of these individual concepts, namely; 1% effect of mass, 2% effect of cushioning and 1% effect of moderator plates. The Vaporfly has revitalised performance running footwear and garnered tremendous interest from: (1) biomechanics researchers trying to better understand the performance increasing mechanisms; for example ‘Is it the foam?’, ‘Is it the plate?’, ‘What internal mechanisms are affected?’ (2) footwear manufacturers trying to develop their own performance running models that are competitive with the Vaporfly, and (3) governing bodies interested in ‘Maintaining the integrity of the sport’. With AFT now common place in road running, innovation efforts have shifted to track spikes and trail running shoes. For track spikes, the demands are generally similar to those of road running shoes