In the fourth century B.C., the Greek philosopher Aristotle laid down some key principles of running form. "Runners run faster if they swing their arms," he wrote. "There is in extending the arms a ...

Wondering why you should strength train with kettlebells when you already use dumbbells? For the insane calorie burn! A study by the American Council on Exercise found that the average person burns ...

Alex Hutchinson is a National Magazine Award-winning journalist and Outside’s Sweat Science columnist, covering the latest research on endurance and outdoor sports. New perk: Easily find new routes ...