Tuck-Ups are a great abdominal exercise because they emphasise both the lower and upper portions of the stomach at the same time.
1. Lie down on the floor with your arms outstretched behind your head. Your legs should be together with your toes pointed as much as possible. (See Fig.1)
2. Start to lift your arms from behind your head, simultaneously lifting the legs and torso. Keep the core and abs under tension.
3. As you raise the legs and torso from the floor, the aim is to tuck the knees as close into the chest as possible. This is achieved by lifting the torso right up, so you are sitting right up on your glutes. Hold for a breath to maintain control. (See Fig. 2)
4. With control reverse the process lowering the legs and torso all the way back to the floor with the arms outstretched.

Fig. 1

Fig. 2