Add Yahoo as a preferred source to see more of our stories on Google. Person doing jumping jacks workout Look, I’m gonna be straight with you – those online calculators that tell you exactly how many ...

Jumping jacks are one of those old-school exercises that most of us haven't thought about since school PE days. Simple, familiar and tucked somewhere in the warm-up section of a workout, they're ...

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.