Clyde1820

Stations like the TechnoGym "low row" can be used for some core engagement as well. As well as the complementary chest press type machine that's designed in a similar format. Just don't use the back or chest support while doing the movement. It'll limit the amount of weight one is capable of moving, without that support, sure. But such devices can be used with a handful of sets for the purpose of the row or the pecs, but with a separate handful of sets specifically for engagement of the core.

Myself, I've got really damaged flexor/groin muscles that preclude the use of much equipment such as the Roman Chair, or leg-raise, or typical ab/crunch stations. But I can use cable cross stations, or things like the TechnoGym "low row", in a manner that engages the core. Perhaps isn't ideal, but it does work.

For abs, one can even lie down on the floor, grab a medicine ball or dumbbell with both hands, raise the ball/dumbbell up "over" the head, and then work with the legs ... flutter kicks, scissors, alternate leg raises, knees-to-chest, all the while counter-balancing with the ball/dumbbell. Doesn't require a machine, as such, and can easily be done anywhere. Can make more difficult via the addition of lighter ankle weights.

Lots of choices, out there.