Planks for abs?

Planks suck. Really, they do. However, if you want to do them and can hold it for longer than a minute, you need to add weight.
The only exception for me is side-planks for obliques. I find obliques difficult to target and side-planks seem to be the most effective for me.

There aren't different exercises for 'flat' and 'bumpy' abs - the difference is just how developed they are and your genetics. 'Flat' abs are just less developed than 'bumpy' abs, combined with low bodyfat so you can still see definition.

 

I would say that if you are going for a flat stomach ab exercises are something to stay away from. All they're really going to do is make the muscle stronger without burning any of the surrounding fat. Jogging, swimming, cycling and weight lifting are all better ways to lose fat. That being said, planks can be an excellent ab exercise because they can be modified for all different skill levels. You can do them with weight, you can do them on one arm, one leg, one arm and one leg - heck, I think the best think I've found is to do them on stairs. They are excellent for adding definition IF you already have low body fat.

 

IMO, planks are good for core strength, not much for losing fat/developing muscle. How your abdominal area looks is determined by your genetics and body fat percentage. Running is a good way to tone your stomach. Watch what you eat and exercise and you'll get to where you want.

 

Abdominal obliques are big, flat, thin muscles that don't really grow outward in size unless you are really working them out hard.

If you develop your obliques enough it will make your stomach area a bit wider, but bodyweight/low weight side-planks aren't going to increase the size very much if at all. For me it has just firmed up the area and defined it a little.

 

If you want abs do v ups and leg raises. For the obliques you can do weight twists, or really anything that incorporates a twisting motion.

 

No, but once I started losing some fat around my waist (I'm lucky, there wasn't/isn't much) side planks were a tremendous help in firming up the area. I found it also gives you a somewhat well defined...groin area...(I'm not a medical terminologist, I just like to work out ).

 

Planks are definitely a good exercise for strengthening the abs. If your stomach tends to stick out a bit, not from fat but from a weak abdominal wall then they'll definitely help. I wouldn't worry about them getting too big, as long as you're not doing weighted exercises.

You could also try stomach vacuums. I've been doing those recently, although I haven't had time to tell if they're effective (my stomach is already pretty flat so it won't make a huge difference for me anyway). Some bodybuilders swear by them though.

 

Try Pilates type exercises.

The muscles that make the stomach look flat/waist smaller are actually UNDER the six pack. The main one is called the transversus abdominis, its hard to target with a lot of exercises but Pilates is big on strengthening this muscle.