Abdominal
crunch

The abdominal
crunch is one of the most popular
abs exercises, and a great way to strengthen this area. The starting
position for the abdominal crunch is on your back, both feet off the
floor, legs forming a right angle, shoulders just off the floor.
Inhale, then simultaneously bring your knees in towards your chest,
while lifting your upper body to an angle of around 30 degrees.
When your elbows touch your legs, pause for a second, then slowly
return to the starting position. Pause again, then repeat. Be sure
to keep the contraction in your abs the whole time. If you allow
your shoulder blades to go all the way back to the floor, then the
contraction in your abs will be reduced, making the exercise easier.
For beginners this is OK, for those that are more advanced, try and
focus on feeling your abdominal muscles working throughout the
movement.
Keep your chin up off your chest, and if necessary gently
support your head by placing your hands at the side of the head.
You can also perform this exercise with your arms straight along
your body, which is a little easier, or with your hands crossed on
your chest, which is harder.
As with all abs exercises, the movement should be smooth, with the
focus on using your abdominal muscles to lift and lower yourself.
Beginners should aim for two sets of 8 - 12 reps; Intermediates two
sets of 15 - 20 reps; Advanced should do three sets of 20+ reps.
Rest for 20 seconds between sets.