Spot on Scrap and Adam, low intensity work isn't the only way to burn fat. Due to excess post exercise oxygen consumption (epoc) you can still benefit in terms of weight reduction from high intensity workouts, as this increases our base metabolic rate. At rest our predominant fuel source is fat, so increasing the metabolism in general, helps burn excess fat. So working those fast twitch fibres in as many ways as possible is the best sport specific training for amateurs.