1- Stand up straight facing a low pulley cable stand, knees slightly bent.
2- Grab the straight short bar on low pulley, with underhand grip (palms facing upward, thumbs away) at shoulder width, arm straight.
3- Exhale and curl the bar up toward your shoulders by bending the elbows.
4- Inhale at the end of the movement, and lower the bar to the starting position, then repeat until you finish your reps.
Tips and Advices:
1- The upper arms should always remain stationary next to your body and only the forearms should move.
2- Keep your back straight though out the exercise.
3- Don't allow your elbows to come forward in order to lift the weight.
4- Holding the bar with wider than shoulder width focuses effort on short head of the bi, whereas a narrow grip focuses on the long head.
Variation:
1- One Arm Biceps Cable Curl
2- Overhead Cable Curl