Is stroke correction the secret to becoming an Ironman World Champion?

You would assume that by the time you're winning Ironman Age Group title you would have your swim technique dialled in. Right? We caught up with the 2015 Ironman Age Group World Champion Malte Bruns to find out what he does in the water and if regular stroke analysis and stroke correction works for an Ironman World Champion then it should work for the rest of us weekend warriors trying to improve our performances.