Some people question why we never focus on just doing abdominal work. My reply is almost always the same - we do abs all the time and you just don't realize it. In order to maintain proper midline stabilization, the core must be strengthened. The core involves not only the abs, but also the spinal erectors. They work together to provide the core strength we need for all of our work. We improve our core strength by engaging in functional movements that require midline stabilization to perform the moves properly. Everything we do, whether we're powerlifting or doing Olympic lifts, engaging our POSE running form, and doing pushups, pullups, and wall ball shots requires a strong core. The more we do these moves, the stronger our core becomes and the greater weight we can lift or move.
Doing abdominal work in isolation provides no more benefit than any other move one might do in isolation. Sure, it might be okay to focus on a particular area of the body on occasion, but true functional fitness requires involvement of the entire core. So, no, we're not going to do an ab buster class by name, but try doing 75 overhead squats for time with 95 pounds and then tell me the next day if you worked your abs!
Click either of the links to hear what Coach Glassman says about abs.