'If you can do it for 4 hours then it isn't challenging. Definitely not stimulating muscle or strength development.'

This is an inaccurate statement because what I'm doing is stimulating muscle & strength development in my body with my workout routine.

If you want to argue efficiency, then fine, feel free. I'm not gonna pretend like I'm 100% certain the exact workouts I'm doing are 100% efficient. I'm building muscle, I enjoy my routine & my health is as good as it's been since I was in college 20 years ago. All I really care about, TBH. 

 Okay