Stretching which part of the muscle?

I have a background in a quite quadriceps intensive sports. That was ten years ago, now just started to practice Muat Thai.

I have always stretched after exercise, but maybe not in a totally correct manner (bending to much back on hamstring stretch for example).

I now about isometric stretching since before and have now started following the "official" Marial Arts Planet program to get to the splits.



Enough with the background, to the question:

Especially when stretching the hamstring, I feel the stretch on different locations depending on hip rotation.

More hip rotation, more "stiff" stretch sensation close to the hip joint.

Less hip rotation, more "flexible" stretches station in the middle of the muscle.



I read about "joint stretching" being the most important part on some stretching website which unfortunately sold a book that I dont wanna buy.

However I didn't feel the scuentifical background was that solid.



So.. What is your operator opinion?