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Running is one of the most effective workouts you can do. The problem? Not only can it be boring, but if you run too long or too often you risk sacrificing hard earned muscle (ever seen a built marathon runner?). Not sure what to do? No sweat. Take a crack at this explosive twist on long boring cardio and you’ll not only preserve the muscle you’ve got but set the stage for more growth to come! Ready, Set, Grow!