A pocket knife

Muscle

Legs

Equipment

Bodyweight

Measured in

Reps

How to do it

Lying on your back, extend your arms along the body and firmly press them to the floor. On the inhale, engage your glutes and lift your legs off the floor. With controlled muscle tension, slowly bring your legs behind your head, envisioning yourself folding like a knife. Then, straighten your legs, attempting the "birch" exercise. Bring your legs back over your head. Keep your hands aligned with your body. On the exhale, gradually lower your pelvis and legs down, one vertebra at a time. If you experience any pain in your neck, back, or shoulder joints, skip this exercise.