Walk into any gym across the world and you'll be met by a sea of elliptical machines and treadmills. If you happen to become a regular at any of those said gyms, you're bound to start noticing the ...

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Most gyms have an elliptical machine. And chances are, someone's on it—and using it incorrectly. The ...