Look, I used to think those “100 jumping jacks = 10 calories” calculators were gospel. Then I started paying attention to real people doing real workouts, and wow – was I wrong. Those generic formulas ...

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." YOU MIGHT THINK back to your childhood gym class and remember learning the basics of physical fitness, ...

Look, I’m gonna be straight with you – those online calculators that tell you exactly how many jumping jacks you need to burn 500 calories? They’re basically making educated guesses about your body.

Real talk: The thought of doing jumping jacks may be only slightly more enticing than burpees. It may bring back memories of pre-dodgeball warm-ups back when dodgeball was part of gym class. Yet, ...