For people who are not strong in their core, activating abdominal muscles may not happen automatically. For these people, you need to be taught how to do a proper crunch step by step, starting with proper core activation.
Core activation is important for protecting the spine from injury any time you move or carry something. Your abdominals are also responsible for keeping your internal organs from bulging out. A hernia (disorder where the intestines push through the weak parts of your abdominals) can be prevented with the right kind of core strengthening.
Please watch this short video on how to activate your core and crunch from your abdominals, not your neck. You can check out the link here: