Thread: Can you give me a good ab workout routine I can follow?

What you should do
Here is what i do
well i do 25 rep of sit ups
and 25 reps of crunches

and then i do another set of each of them

I'd like to follow this routine for at least a month.
I'm not chubby or anything, I've already lost 18lbs in the past 2 months doing cardio workouts. I weight 155 and my height is 5'9, i'm 19 yrs old.
Best and informative answer gets 10 points. Thanks!