You don’t have to have an ab machine to work on the abdominal muscle group – a coffee table will do fine. Strengthening our core is very important for healthy posture, however if the abdominal muscles are weak, when we do work on these muscles, often the neck is strained in the process. This is not ideal.
So keep the neck relaxed and stable – better to do less reps correctly than more with neck strain. Isolation is always the key. As always, aim to do as many reps as comfortable in your two minute time frame.