For years, sportswear brands Adidas and Nike have competed to design record-beating trainers . As Adidas wins the race to record the first official sub-two-hour marathon , Dezeen plots a brief timeline of the so-called battle of the super shoes. Marathon records have tumbled in the last 20 years, with most experts agreeing that advancements in running-shoe technology have played a significant role. Spurred on by the target of recording the first officially recognised sub-two-hour marathon, Adidas and Nike have invested heavily in developing a series of record-breaking trainers. At times it has proved controversial, with claims that the focus on footwear amounts to "technological doping" , but the trend shows little sign of slowing down. In recent years the title has been broken by athletes wearing the latest innovations developed by both brands, as the world record edged closed to dipping under two hours.…