Strengthen muscle's belly.

And if weight loose is fast, thus a muscles belly will suffer more, thus regular these exercises repeating.
Lie on spine, hands put for a body along, palms touching a floor, raise a strengthening in knees a legs on a high till 30 cm, and two times slightly to beat a one foot about other, repeat this 7 times,and move is steady.
Lie on spine, raise a high hands up, and put on a floor, and after energy swing to front with hands, do not move a heels from floor, if it not possible add support for edge bed or shelf,straight out spine, move hands to sides, and fast move back, slowly return back, repeat till 5 times.

Lie on a right side, bended in elbow right hand to put under head, left on waist. Raise left leg up, do not bend in a knee, and low. Repeating till 5 times,after return on an other side and to do other leg, breathe out doing,with raising a leg.