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.

Editor’s note: Dana Santas, known as the “Mobility Maker,” is a certified strength and conditioning specialist and mind-body coach in professional sports, and is the author of the book “Practical ...

Core-stabilization training was derived from physical therapy in which injured patients needed to improve core strength after an accident or surgery. This specialized category of exercise made its way ...