Russian twists are great for targeting your obliques. To start, sit up straight on the floor with your knees bent and heels about a foot away from your body," Lagree explained. "Then, slightly lean back without rounding your spine. This part is particularly important (and yes — it's going to be hard!) but don't let it curve or the exercise won't work. Hold a weight with both hands in front of you. Then while pulling your belly button to your spine, twist slowly to one side. Hold for three seconds and inhale, then rotate to the other side." He recommended working up to 16 full rotations (left and right is one rotation).