WINDSHIELD WIPERS

Lie on your back on the floor, and lift your legs so that they're fully extended and perpendicular with the floor. Keeping the backs of your shoulders on the floor throughout, using your arms on the floor at your sides to keep you stable, lower both legs (still fully extended) to one side. Touch the floor with the outside foot, then return to the start position (legs vertical). Lower to the other side, then again return to start. Go back and forth from side to side (like windshield wipers on your car) until you've completed all reps on both sides.