What connects the trainers on your feet to a jumbo jet flying 40,000 feet up in the air? The trainer is a miracle of modern science. The average pair lasts just six months, but in that time, they will have run 3,000 miles, absorbed 400 litres of sweat and withstood 400 tonnes of impact. How they survive this battering is down to some miraculous chemistry that lurks beneath their flashy skin - a hidden world of impact cushioning gel, moisture absorbing insoles, and breathable foot-hugging coatings. So tune in and explore the chemistry that propels us around the planet.