Despite their abs-firming reputation, crunches aren’t the shortcut to a six-pack. In order to strengthen your entire core, you need to target all of the muscles in your midsection, and this workout will do just that.

Fitness trainer Sam Skelton will lead your through a quick, 13-minute routine that goes beyond simple sit-ups or crunches. These three key moves will strengthen your deep core muscles (the ones that give you stability and protect your spine and back). Each move will have a few progressions that’ll really fire up your deep abdominals and challenge your balance. You’ll end with a well-earned stretch.

To recap, each move below features a progression element. The entire circuit will be repeated before moving to the next move.

  • Dead Bug Progression
  • Bridge Progression
  • Plank Progression

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