This deceptively simple exercise is the secret to rock-hard abs. The plank position engages the transverse abdominals, which aid in stabilization of the spine and pull in the tummy. It helps develop strength in the core, shoulders, and glutes.


  LEVEL 1: Plank
  LEVEL 2: Diagonal Mountain Climber
  LEVEL 3: 1-2 Push

Place your forearms on the floor and extend your legs until your body is balanced between your toes and forearms. Your elbows should be directly beneath your shoulders and your body should form a straight ...

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