Lie on the floor with the legs extended straight and your fingers at the sides of your head. Simultaneously perform a sit-up and bend your knees to lift them up, rotating the trunk to bring one elbow to the opposite knee. Hold this position.
 
Return to an extended body position without allowing the heels to touch the floor, and pause in this position before starting the next rep, rotating to the opposite side.
 
Purpose
Including pauses increases the demand on trunk/hip control and adds isometric stabilization of the trunk with rotation.
 
Programming
Perform sets of 10-30+ reps.