The alternate dumbbell preacher curl is a good exercise for isolating the biceps and making them work independently. Adjust the height of the seat on the preacher bench so that when you sit on it, the back of your upper arms restcomfortably flat on the padding.

Grab a set of dumbbells and sit on the preacher bench.

Your arms should be resting on the padding and be around shoulder width apart.

Allow the weight to drop and arms to fully extend. This is the starting position for the exercise.

Starting with your weakest arm, slowly curl the dumbbell up, squeezing the bicep at the top of the movement.

Lower the weight back until your arm is fully extended, and then repeat for the other arm.

This is one rep, now repeat to complete the set.

Preacher Curl Tips:

Control the weight, lowing it slowly.

As a general rule, always work your weakest body part/side first.For most people this will be their left arm.

Really focus on the contraction and stretch on the bicep muscle. Work that mind-muscle connection!