Hold a barbell with both hands and your palms facing up; hands spaced about shoulder width. Place your feet flat on the floor, at a distance that is slightly wider than shoulder width apart. This will be your starting position. Lower the bar as far as possible by extending the fingers. Allowing the bar to roll down the hands, catch the bar with the final joint in the fingers. Now curl bar up as high as possible by closing your hands while exhaling. Hold the contraction at the top.