Ok there was a good conversation starting on Twitter re: weighted vs unweighted ab excercises. Here’s some current research:
http://www.flexonline.com/training/abs/slow-vs-fast-rep-speed
That being said, a balanced approach to training your abs (and core) that recruits different muscle fibres AND different muscle groups is probably your best way to go.
My standard ab days include some variation of the following set:
Set #1 (Repeat 3-4 times)
- 10x hanging leg lifts (start with knees bent and as you develop strength, move to straight legs. Remember, unless you’re breaking the 90-degree plane, you’re mainly working your hip flexors, so get them up there!)
- 20x weighted slow swiss-ball crunches - I’m using a 45lb plate (crunches on a ball requires you to stabilize laterally. Play with your foot positioning to balance off stability with safety. It’s important not to bounce, and to get the most out of the range of motion afforded by the ball - go slow all the way back and all the way up)
- 20x ‘crossing’ fast swiss ball crunches (Different muscle fibres this time, and you recruit the serratus and obliques)
- 30-45 second rest.
Set #2 (4 times)
- 12x, 12x , 8x, 8x Cable crunches (If you’re new to cable crunches,start light to get the range of motion correct, and use a rope. Lots of videos on line showing good form and bad form. My first two sets are moderate weight, my last two are heavy)
- 30x Mason twists (usually unweighted, but if I’m feeling strong, I’ll grab a 35lb plate, or a medicine ball if one is handy - listen to your body, and keep those legs up!)
Miscellaneous
- If you’re on a bench on a chest or arm day, why not work in a set of crunches on the bench. Add decline crunches on a chest day supersetted with decline bench press or dumbbell press to get the most of your time!
- Swiss ball pikes (get in a push=up position with your legs on a ball and ‘pike’ your legs up. I dread these, but try to do them a couple times a week
There’s a ton of different approaches and exercises out there for your abs, and don’t even get me started on core training (Plank & side plank FTW! These days, its all about the core baby.). Find what works for you.
NOTE(S) OF CAUTION: There is a lot of ‘controversy’ regarding how hard you should train obliques and transverse abdominals, if at all. This all depends on what your goal is, so again, not everyone is training for the same reasons. Obliques and transverse abdominals lie on the side of your abs, effectively under your ‘love handles’. For obvious reasons, if you train them, like any muscle, they will grow. Many body builders and fitness models avoid training obliques and transverse abdominals like the plague, to emphasize a V-taper to the waist. MMA fighters and football & rugby players train them hard to increase lateral core strength. The same goes for really heavy weighted crunches and cable crunches, although to a lesser degree as a decent chest will complement solid abs. I work my obliques and transverse abdominals really hard by adding in a couple other exercises with big weights as I’m more focused on functional strength, and less on pure aesthetics.
All I have to say is figure out what your goals are in your training, read as much as you can, and if you have the resources, work with a trainer to help achieve your goals!