There is a huge variation in rotational range of motion in the shoulder, but somehow many people are not aware of this.
For many people, as soon as the arm goes behind the back in a kimura, they are done, and any pressure there is going to result in some sort of shoulder strain.
On the other hand, there are people who can twist and fight quite awkwardly from that position, so many people feel a need to really crank from that position, which is bad for group #1. Falling into group #1 myself, I find that I have to tap to Kimuras basically as soon as I lose any anchoring grip on the front of my body, as I generally don't trust people to slow down when they are finishing the lock.
For many people, as soon as the arm goes behind the back in a kimura, they are done, and any pressure there is going to result in some sort of shoulder strain.
On the other hand, there are people who can twist and fight quite awkwardly from that position, so many people feel a need to really crank from that position, which is bad for group #1. Falling into group #1 myself, I find that I have to tap to Kimuras basically as soon as I lose any anchoring grip on the front of my body, as I generally don't trust people to slow down when they are finishing the lock.