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 ...

FITBOOK author Nina Ponath loves challenges—this time: 10 days of jumping jacks. Photo: Getty Images / Antonio_Diaz; Collage: FITBOOK Jumping jacks in all variations–FITBOOK author Nina Ponath did at ...

Jumping rope is an effective workout — it can help you lose fat, build muscle and improve agility. Plus, they are a portable and affordable piece of exercise equipment, so they're great for travel or ...

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, ...