Tie a superband to a machine or squat rack.

Loop in a small weight plate (2.5 lbs).

Standing in a staggered stance, hold the free end of the band in both hands.

Throw the hands forward into full arm extension and hold the position until the weight plate stops swinging.

Keep the shoulders engaged and core tight to disallow the arms to move around freely -- you want the upper body to be as rigid as possible.