6 abdominal workout for lower abdominal area - you will work on entire abs, don't worry ;) Exercises include variations of jackknife sit ups, half jackknife sit ups, rowing, planks. These exercises are advanced, and if you have problems with you back, it is best to avoid them, or at least add support by putting hands behind your back (support part of your body weight by putting hands behind back). If you do not find these exercises stimulating enough, I suggest you use weights (2-5 kg) and perform them with additional resistance. At the end of each set you must perform 2 back exercises that stabilize and strengthen back muscles (this is really important). Perform at least 2-3 sets.
Advanced training for lower abdominal muscles - avoid if you have back problems or adjust workouts