Have 34 minutes to spare each week? Then you can put on muscle and lose fat fast. Sounds like magic, but it’s the science of making workouts smarter and more efficient—and it’s scientifically proven.

When people talk about muscle growth, you may think of protein-rich foods or supplements and strength training. These are key ...

I didn’t know I could love working out so much until I tried my first group fitness class. I’ve been active my whole life, but after having my third kid at 34, I struggled to find a workout that stuck ...