Pilates is great for core strength, I go to a class once a week, our teacher is excellent, every week she has a different routine.
Last week we were doing planks with a foam roller under our knees, then under our toes (reduced balance = more control)! Then just to make it really hurt, push up from your elbows onto your hands (one hand at a time), without any twisting, then back down again.
I was still sore two days later, and Im still a fat fella!

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