Set an incline bench to about 45°, and place it in front of a high-cable pulley with a short straight bar attached. Grab the bar, and sit back on the bench. Your arms should be straight and angled upward toward the pulley. Without any shoulder or upper-arm movement, strictly curl the bar toward the forehead. Hold the peak contraction for 1 to 2 seconds, actively flexing the biceps. Slowly return the bar to the starting position.