Are "super-shoes" giving some runners an unfair advantage?

The Kenyan runner Kelvin Kiptum has just set a new marathon world record. He did it wearing “super-shoes”. Sports brands are racing to design new trainers which are lighter and have clever geometry to propel runners forward. Bobbie Jackson from BBC Sport and Celestine Karoney from BBC Sport Africa discuss whether they really make a difference - and is it fair if some athletes wear them? And in the week of Halloween and Day of the Dead, Mathias Clasen, Co-Director of the Recreational Fear Lab at Aarhus University in Denmark, answers our question; “Why do some people love scaring themselves?”

Email: whatintheworld@bbc.co.uk WhatsApp: +44 0330 12 33 22 6 Presenter: Hannah Gelbart Producers: Mora Morrison, Benita Barden and Julia Ross-Roy Editors: Verity Wilde and Simon Peeks