A CSCS trainer shares an 8-minute standing routine that targets abdominal fat after 50 -- no machines or floor work needed.

Core training has always been part of military PT and fitness testing. From crunches to sit-ups, flutter kicks, leg tucks and plank poses, the U.S. military uses many exercises to test core strength.

If you’re after six-pack abs, you’re in the right place. The core workouts below have been hand-picked by top trainers to help you build muscle and forge a rippled midsection with enough definition to ...