roman chair leg raises

I've recently joined a gym with the main goals of putting on size and strength. Part of the program that was done up for me is roman chair leg raises - now I'm not sure if I'm doing them incorrectly or not, but when I do them I tend to feel them more in the hip region than my lower abs (I'm assuming the exercise is aimed at lower abs).

I'm studying human movements at uni, and I was taught that strengthening hip flexors is a NO NO. This is because the hip flexors are only designed to stabilize the hip joint and are already very strong because they're so commonly used. Over-working the hip flexors can lead to them becoming 'too strong', which results in a rotation of the pelvis due to shortened hip flexors which can cause some major lower-back problems.
We were taught that the straight leg raises you do when lying on your back have little benefit for your abs, but they do really work the hip flexors - so were told that this exercise should not be used.

So basically what I'm trying to ask is this - are the roman chair leg raises a bad exercise? (ie. do they work the hip flexors)
Or am I just doing them wrong? (which I would be very surprised about because it seems like a simple, straight-forward exercise)

If they are a dud exercise, can anybody recommend a good lower ab exercise that I could substitute into my program to replace the roman chair leg raises?

This is my first ever post on ausbb!
Hope it isn't a stupid question and it contributes somewhat...

The only time I've ever trained abs lately was knees to elbows on rings, really sore all over the abs every time I did it.
You could do them on a straight bar too I suppose.

I do hanging leg raises and this sure smashes my abs. Maybe it is because you are knew to the excersize? Maybe you are weak in your hip flexors? Do you squat often?

I am surprised as a student of human movement that you are asking an internet forum and not your lecturers though.

yeah could be because i'm new...
pretty much i asked on the forum because it's quicker and easier than asking a lecturer when i'm just after some opinions.
i'll keep at it for now and see how I go

cheers guys.

There are probably only few people who could really answer your question in relation to the Hip Flexor. I don't see it as a bad excersize myself.

Hanging leg raises will work mainly the hip flexors.

The abs shorten the distance from pelvis to sternum and vice versa so the best exercise to target then directly is crunches and reverse crunches.

Abs are also involved in stabilizing the core in heavy compounds like squats and deads.