Short on time? Don't skip the strength-training session — get playful with the plank! By doing multitasking variations of this basic move, you can target your arms, back, core, legs, and booty to chisel out a stronger, more toned you.
6 Must-Do Moves With a Stability Ball. I changed the inner thigh squeeze for sitting twist with ball for obliques and a bit more of an ab workout. Loved this one. Takes about 10 minutes. The first two exercises are a bit hard on the wrist so mix it up if you need. Good workout!!!