Trainer Luke Jones shares a six-minute ab workout that activates deep core muscles, improves posture, and leaves you feeling the burn long after you're done.

So, in the name of curiosity (and core strength), I decided to try a workout created by Justin Gelband — a world-class ...

It's well established that a strong core can help with posture and back issues, and properly executed sit ups can contribute to a stronger, more stable core. "Regularly doing sit-ups or crunches can ...