This week, the team looks at advances in sporting technology. The world 400,000-metre champion, Ros Lamb, demonstrates a new serum (based on caramel-flavoured rocket fuel) which is said to help her to run at up to 3,500 miles per hour. And Ros faces this week's Challenge - can she run the 524 miles from London to Aberdeen in under five minutes? (But it was not foreseen that she would arrive... see more