The power of the gym to improve almost every facet of your sporting performance cannot be denied, but training outdoors-under cerulean skies and surrounded by lush greenery -adds a certain joie de vivre to your workouts that even the plushest indoor training facility can’t hope to match. And if you’re taking on a race or outdoor event this summer, working out in an environment similar to the one you’ll be competing in will make you far more comfortable on race day.