I need a stability ball. A stability ball is a great addition to standard workouts as they help core muscles to activate. Core is what supports your posture and daily functions, but often overlooked and underutilized while working out.
Jackknife: Sit on top of a bosu with legs extended, and place hands on the ground behind you, fingers facing forward and elbows bent [a]. Raise legs at a angle as you lift torso, straightening arms [b]. Return to starting position and repeat.