Concentration curls

Step 1: Start by sitting at the edge of a bench holding the dumbbell in your right hand. Let the right arm straight down with the elbow resting on the inside of the knee

Step 2: Lean forward so your torso is your legs and place the left hand on the left knee. Make sure to keep the back straight and firm at all times. Start the curl motion using the elbow as the pivot point.

Step 3: Lift the dumbbell to the shoulder level and pause momentarily. Slightly curl the wrist to make the dumbbell faces in parallel to the floor (as illustrated in pictures). This will activate the "bicep hill" and allow the formation of the "boulder" shape.

Avoid this mistake: Make sure to keep your back straight at all times. It has been observed that during this exercise many individuals abend their back unintentionally. Not only does that decrease the effectiveness of the workout, but also hinders in optimum muscle growth and also causes lower back pain in the longer run.

Step 4: Slowly return to the starting position. Repeat.