YOU MIGHT THINK back to your childhood gym class and remember learning the basics of physical fitness, setting a foundation for the grown-up workouts you continue to do today. While you likely keep ...

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.

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 ...