For the last two months I've stopped doing sit ups entirely and focused more on my core with raised side planks, throwing a 15kg plate behind me from overhead on alternate sides, 'windshield wipers' and dragon fly's on a bench. I initially found the last two exercises very, very difficult but am now getting much better form and finding them more achievable. The thing is, my abs are showing a LOT more now than when I was doing endless sit ups and crunches and my core feels tight and stronger than I've ever felt. Has anyone else had a similar experience? When I'm in the gym I'm now getting a few younger guys asking me how to do the wipers and flys and they seem very surprised that an "old guy" (I'm 45) can do these exercises when they really struggle with them. What I'm seeing is big, muscular guys who seem to have a weak core and it's making me realise that people can be fit and strong without the need for huge muscles. It's been a real learning curve and now I want to take it to the next level and want to know if anyone out there can recommend any other good core exercises that they've had good results with. Thanks for your input and Grok on!