Strengthen your core after 55 with 4 chair drills that train rotation, lower abs, and anti-rotation without floor strain.

While the plank is an excellent core exercise, several other options can strengthen your core. You can do these bodyweight exercises anywhere, and they don’t require equipment.

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.

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Deep inside Earth is a solid metal ball that rotates independently of our spinning planet, like a top whirling around inside a bigger top, shrouded in mystery. This inner core has intrigued ...