This video will show you how to build your arms with lying single arm dumbbell extensions. Darin Steen, creator of the Fat Loss Lifestyle 12-Week Body Transformation Program, Shows you how to build up your triceps with this exercise of the week! Make sure to get your shoulder off the bench and keep your elbow nice and high. Bring the dumbbell down to your cheek and exhale as you bring it back up. Use your other hand to stabilize your arm. For a more intensive workout, after the extensions get a nice isometric squeeze of your triceps and bring your palm down towards the floor and keep squeezing for about 5 to 10 seconds!