But the six-pack sure does look good. Haha!
Functionally, I rarely focus on rectus abdominus. In every day life, pulling our ribs to our pelvis isn’t a natural thing. In fact, flexion of the spine is often seen as a bad thing. More often, it comes into play in an isometric sense (non-shortening fibers). When we lift heavy things, we focus more on transverse abdominus. Of all the muscles of the abdomen and back, I’d say rectus abdominus is the least of our concern. It is the outer, superficial layer and is kind of a last resort muscle.
That being said, R. abdominus is really sore on me right now. I did crunches (with one of those funky crunch things you buy on late night TV for $19.99). As much as CrossFit’rs, powerlifters, and any other serious lifter laughs at crunches (except bodybuilders), they do work. Even though R. abd is the primary focus and not as important, you can’t help but enjoy working them.
I actually worked to fatigue several times last night and even had to rest to complete my reps. They are surely aching today.
Go ahead and work them now and then. I give you permission.