How can I do more crunches in 20 minutes?

Start off with a manageable number. Then slowly increase the number you do everytime you do the crunches. Eventually will build up those abs and do much more then you already can!

If you work on it every day you should be able to increase your number. You could also do other ab workouts to keep your abs in good shape.

Arms widespread with hands behind your ears like you have wings, legs bent with heels 6 inches from your rear, point chest toward cieling and push 5-6 inches off the ground, it doesn’t feel like you are doing much until about after 15 reps, then the burn sets in.

I found that if you increase the intensity of the crunches, your body will get accustomed to doing more of them. What I mean by this is:

I needed a minimum of 45 crunches for MEPS, but the goal was 80. On certain days, I did 20 extremely slow crunches to increase the contraction of the abdominals. Then, I performed 20 as fast as I could while keeping form perfect. Then, 20 at medium speed. After a few days, the added intensity will become more adaptive and you’ll be able to perform more crunches to get to your goal. It works a lot easier if you use a weight such as 10lb. or 45lb.