The heavy left arm biceps curl is an exercise that targets the biceps muscle. It is performed by holding a dumbbell in your left hand and curling it up towards your shoulder. The weight of the dumbbell should be heavy enough to challenge you, but not so heavy that you cant complete the exercise with good form. To do the heavy left arm biceps curl, stand with your feet shoulder-width apart and hold a dumbbell in your left hand. Your palm should be facing towards you. Bend your elbow and curl the dumbbell up towards your shoulder, keeping your upper arm stationary. Slowly lower the dumbbell back down to the starting position. Repeat for the desired number of repetitions.