Amy and Emily speak to Sam Scott (York University,Toronto, Canada) about his recent research into high intensity interval training, and Ruth Wood (University of Southern California, US) and Ildus Akhmetov (Liverpool John Moores University, UK) about how testosterone can affect athletic performance.  They also discuss: can you eat before you swim? Could Forrest Gump really have run that far? And how fast can you swim through syrup?