World Athletics has announced significant changes to its rules that will outlaw some variants of Nike's Vaporfly running shoes and introduce strict limits to the technology developed for any future shoes used in elite competition.
The sport's governing body said that with immediate effect, road shoes must have soles no thicker than 40mm and not contain more than one rigid, embedded plate.
The Vaporfly shoes used by Eliud Kipchoge (below) to run the first sub-2 hour marathon and by fellow Kenyan Brigid Kosgei to smash the women's marathon world record both contained triple carbon plates.
The new rules also state that, from 30 April, any shoe used in competition must have been generally available to the public for four months - putting paid to the use by Nike and others of prototypes by its athletes in major races.
World Athletics' review concluded that the new technology may provide a performance advantage and could raise concerns that it might threaten the integrity of the sport, and it has recommended further research.