For cyclists, measuring force is an everyday part of training. Cyclists can use gadgets to calculate the force applied to a bicycle pedal when in motion, wattage being one of the most important factors in the results. For swimmers, strength and force measurements could be just as useful, but how force is exerted in the water isn’t as clear as in cycling. How much energy does a swimmer use during an arm pull? In which direction does the energy go? What kind of effect does it have on the swimmer’s performance? A Finnish startup is asking exactly those questions, and finding the answers in a new technology that’s barely larger than a box of Tic Tacs.

David Marsh is one of the most respected and successful swimming coaches worldwide. The 60-year-old American coached around 50 Olympians from various nations and is currently head coach of  the "Team Elite". Olympic gold medalists Ryan Lochte and Anthony Ervin, among others, trust his guidance. At the Olympic Games, Marsh was part of  Team USA coaching for four times, in Rio he was even named  head coach of the women’s swimming team. We talked to the top coach about  US swimmers always managing to be on the top of the podium at the Olympics, and what it means to be a swimming coach today.

It's this magical lane in the middle of the pool, reserved only for the fastest. It's where stars are born, medals are won and tears are shed, when some outsider on another lane hits the wall first. But what's it like to live your life in the fast lane? And how do you get there?