Torch Fat and Build Muscle With the Tabata Workout — It's Only 20 Minutes

Reps: 20, alternating sides

Lie on your stomach with your arms reaching overhead, pulling your abs away from the floor to protect and lengthen your lower back. Lift your legs, arms, and head off the mat.
Keeping your knees straight, lift your right leg and left arm higher toward the ceiling. As you lower your right leg and left arm, lift your left leg and right arm up to complete one rep.
• Continue alternating sides in a slow controlled manner, keeping your torso stable.