When it comes to strengthening the abdominals and core muscles, it is always great to have an arsenal of routines, because your body needs change to create results. Doing regular crunches with your feet placed on the ground are great, but you will get used to that exercise quickly. When that happens, lift your feet with a slight bend in your knees, this will make the hip flexors from helping you out. But we are here to talk about the next level of abdominal training and that involves hanging crunches.
Hanging crunches are challenging because you have to hold your body from a pullup bar, so your muscles in your hands, forearms and upper arms will get quite fatigued (if you are new to this exercise). Watch this video to see the regular hanging crunch.
For those who need a more advanced Hanging crunch, then you want to add resistance and that can be done with your own body weight. I have attached another video to show you how this is done.
Both are great exercises, so take your time to build up your repetitions, but you will get there.