One more thing that I would like to point out, as girls we want to have nice abs but we also want to have a thin waist, so I would recommend to avoid doing too many side plank holds and do more side to side bends. To make my waist smaller I do side bends about 4-5 times a week 20 – 60 reps, 20 at a time. Side to side bends really help to tighten the side muscles without bulking them up. You can do that while you watch TV, or right after you wake up in the morning. If you are a guy then you can skip on side bends and do side planks holds instead.