i heard doing cardio for 20 minutes and then doing ab excersies help flatten your stomac i did it for a week and i lost and inch off my waist. then i got busy with school anyway i want to start again but im going somewere theres no treadmil but i could bike ride well any way i was wondering if bike ridding will work to. do i have to bike ride loner then 20 minutes ? thanks =]

Well, if you ride your bike for 20 minutes and only make it half a mile it probably won't benefit you the way you want it to. Riding your bike is good way to start getting active, but if you're looking to get a good physique there are probably better ways to do it. Do you ride your bike on a path? Why not alternate riding your bike and jogging? Or do exercises other than just those that are supposed to target your abs? You can't get a flat stomach without losing overall body fat, and you'd probably benefit if you started doing exercises that work your whole body, too.

When I go on bike rides, it takes me 5+ miles of bicycling before I start to sweat. A biking for 20 minutes exceeds 1 mile. Because running a mile usually only take 10 min average and that's at a slow running rate. I can run a mile in 7 minutes. If you're bicycling, I recommend it for an hour or more.

Ab exercises don't flatten your stomach. You should still do resistance training, but not under that presumption.

my response is pretty late here but in my professional and well regarded opinion as they usually are with the rare exception of hemorrhage and various internal bleeding, i would suggest with prior warning that it may not be the optimal but perhaps best option available, that you should probably, but not certainly… now what were we talking about again? …ah right, you should try swimming! swimming is the best work out there is right up there with the running of the bulls and professional dodge ball. Good luck

...on top of the ab excercises of course. happy thrusting!