Re: Nail physics exam.
In general, almost everything CF does involves core strength and this is why I love it. Just do a few warmup situps before each WOD as part of the CFWU. Whenever you do squats, burpees, any olympic lift, etc. you are using your core- your abs- your situp muscles.
It is funny how CF works- You can do stuff you think is totally unrelated then come back to a lift you have not done in a long time and hit a new PR.