Long time reader, first post!
I've been prioritizing my abs recently to try and get some more size and shape in my rectus abdominis muscles. Using some weighted crunches on a bosu ball and weighted incline situps I've been able to increase size and visibility over the last couple of months.
Does anyone know if adding a twist somewhat isolates the left or right 'ab' muscle? It seems to if I just feel my upper abs with my hand while twisting my torso (one side of 'six pack' seems contracted, other seems relaxed). If so, it seems like there might be a benefit to working the left and right side of your abs (rectus abdominis, not obliques).
Any suggestions or pointers? Any other good movements to increase strength and muscle size here?