We talk to athletes at last Sunday's Muller Indoor Athletics Grand Prix in Glasgow ahead of this week's World Indoor Athletics Championships in Birmingham. We hear from 2012 Olympic 110m metres hurdles champion Aries Merritt from the United States and reigning World and Olympic women's pole vault champion Katerina Stefanidi from Greece. And we talk to South African fast bowler Hardus Viljoen, one of only 20 players in the history of Test cricket to take a wicket with his first delivery.
