Considering a new fitness challenge? Experts say there are benefits — but it's not for everyone. (Getty Creative) ...

Operation 66 has joined the long line of viral fitness challenges promising to help you overhaul your health. Like the 75-Hard, 75-Soft, and Winter Arc challenges, Operation 66 is designed with ...

The challenge is a 28-day customizable workout plan, with follow-along video workouts led by five different trainers. (No guesswork—and lots of variety.) The WH Flex Challenge is free for WH+ ...