Core strength is at the center of any conditioning program. There are entire books dedicated to strengthening your abs. However, since kicking isn’t done while on your back, Sprague The Leg encourages creativity in this area. Any gym has Swissballs, because they’re an excellent resource for building stability, balance, and strength.
Deceptive, but effective exercises for building strength are Swissball Circles. Take a shoulder-width stance with your feet and place your forearms on top of the Swissball so you are in a bridge position. Make sure not to let your hips sag down, keep them straight and squeeze your abs tight. Using your forearms to move the ball, make ten small circles in a clockwise direction and ten counter-clockwise. After the first set of small circles, try making bigger circles with the ball throughout each of the next three sets.