How do I work out my lower abs while having a hip flexor (illiacus) injury?

Question

About 25 years ago, I had a partial tear in my hip flexor (specifically illiacus muscle). It eventually got better but I didn't rehab it properly at the time. As a result, I have a specific spot in my hip flexor that is prone to overuse injury. When it flares up (every few years), I have to avoid working my hip flexor while it heals.

All that is fine and is just part of life for me.

The problem is: I can never find a way to work my lower abs while laying off my hip flexor. Is there a way to do that? So, I still work my upper abs through crunches and my obliques (I avoid things like bicycle crunch, but I can do things like a russian twist and side-to-side stick exercises). And, I also do planks which I guess does also work out the lower abs a bit. But, is there something more that I haven't thought that I can do for my lower abs? I normally do reverse crunches and leg lifts. Both of those I can't now do without aggravating my illiacus. I know that there if I am able to use perfect form, then I can supposedly do a reverse crunch that activates my abs and not my hip flexor (I have seen suggestions like keep you hip slightly off the ground and squeeze your glutes), but I have tried it and I am not able to achieve that level of perfect form.

Is there another way to work my lower abs without aggravating my hip flexor that doesn't require superhuman observance of perfect form?

Answer 1

There's no such thing as a "lower abs" exercise, as there aren't separate upper and lower abdominal muscles, there's only the rectus abdominis, and it does not have different origin or insertion points at different heights that would be required to allow it to even possibly have different fibres dedicated to causing flexion in the upper vs the lower sections of the lumbar.

When people use the term "lower abs exercise", they're actually typically describing exercises that are specifically for the hip flexors.

I know that there if I am able to use perfect form, then I can supposedly do a reverse crunch that activates my abs and not my hip flexor

This is not the case. The reverse crunch is a hip flexor exercise, and it is completely impossible to do it without using the hip flexors.

If you're having occasional hip flexor pain, your best bet would be determining a type and intensity of hip flexor exercise that you can tolerate without provoking that pain, and forget about the idea of using an obsessive focus on form to try to eliminate the use of the hip flexors.