Will renegade rows make your obliques too big? I do them with very light weight, but I don´t want my obliques to grow too much. And will they work abs overall?
No weight bearing exercise is going to put on muscle mass indefinitely unless you are constantly increasing the weight you are using. If you get to a point where you don't want to grow any more, then drop the weight you are lifting down a notch. There's no chance of you accidentally getting too big without noticing . I didn't actually know what a renegade row was, but I looked it up and it looks pretty much the same as a normal row, but from the plank position. Is that what you're talking about? That will target your abs, but probably not much better than a normal plank would (i.e. not very effective on its own).
so the plank is better then? I had read that the renegade rows worked your abs harder than a normal plank
No, I don't think the plank is very good; I was referring to the plank when I said it wasn't very effective. I've held a weighted plank for 5 minutes and I just stopped because I got bored and it wasn't doing anything. Renegade rows will provide a better 'workout' for your abs than a normal stationary plank because they will be under more strain to keep you stable, however it still won't be a very good ab-targeting exercise. Doing crunches for 10 seconds will most likely be more effective for your abs than doing the plank or these renegade rows for an extended period. Rows target your lats primarily (lats are your back muscles that flange out to the sides and can be seen from the front - Latissimus dorsi muscle - Wikipedia, the free encyclopedia. They aren't the same as your obliques, although they sort of follow on from each other). These renegade rows may target your obliques as well, but I'm not sure and I haven't done them myself. If you want to target your obliques then you'd probably be better off using another exercise.