Step by step instructions
Stand on right leg with knee slightly bent. Raise left knee until it's straight out from left hip. Extend right arm overhead, left arm hangs by side.
Brace core and begin to hinge forward from hips, extending left leg straight behind hip and "windmilling" arms so that left arm extends by head. Continue to lower until torso is parallel to the ground (body forms a straight line from left heel to hand). Slowly return to start, keeping left foot raised off the ground the entire time. That's one rep. Complete all reps on one leg, and then repeat on the other side.