Uh, sure. Do leg extensions if you want. Generally they're frowned upon but like everything in exercise science there is some debate and shifting of opinions. Sort of like the notion that weak VMOs are the source of patellar pain and that targeting them leads to positive outcomes.
You sound like you want an argument. I'm not interested. I am proud to say I am a relative newcomer to proper strength training. I can say that your arguments do not agree with anything I've come across yet, but hey, if it works for you, go for it.
Crunches are overemphasized and should take a back seat to exercises which train your real core muscles. Most people don't need them. They need a stronger posterior chain, obliques(and all the little core muscles), back extensions and training on proper breathing.
You sound like you want an argument. I'm not interested. I am proud to say I am a relative newcomer to proper strength training. I can say that your arguments do not agree with anything I've come across yet, but hey, if it works for you, go for it.
Crunches are overemphasized and should take a back seat to exercises which train your real core muscles. Most people don't need them. They need a stronger posterior chain, obliques(and all the little core muscles), back extensions and training on proper breathing.