The Swiss ball side plank is an advanced core-strengthening exercise that specifically targets the obliques. This exercise will also improve hip mobility and stability.
Lie on the floor on one side, placing your forearm on a Swiss ball with your shoulder directly above your elbow. Place your opposite hand on your hip and fully extend your legs, placing one foot about two feet in front of the other.
Brace your core and raise your legs and hips so your body forms a straight line. Hold the position for the prescribed time, then lower your hips to the starting position.
Squeeze your glutes while holding the plank so your hips carry the majority of the weight.