MUSCLES ENGAGED Obliques Many people put a lot of focus on working their abs but forget their surrounding neighbors; the oblique muscles. Obliques serve as stabilizers, and are used in almost every physical activity. Exercising your obliques should be a very important part of your workout program. Shoulders The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well. Equipment Used Dumbbells The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs (one for each hand). Dumbbells vary in weight from 3lbs. up to 150lbs. Exercise Instructions Step 1 Start in a t-bar side plank with your hips raised high and your feet stacked on top of each other. Hold a dumbbell in your hand held above your shoulder. Step 2 Rotate your body and twist the dumbbell underneath your body. Step 3 Rotate back up to the starting position, fully contracting your posterior deltoid at the top of the motion.