So I was trying to take someone's back from DLR guard in no-gi class tonight and his defense was to fall forward and kneel down, but I already had a strong grip around the waist so I just pulled him backwards to take his back. Then he yelled at me like "DON'T DO THAT! NEVER DO THAT, YOU COULD BLOW OUT MY KNEES!" I was pretty surprised, I've never heard of this before as being something dangerous that you should never ever do. Do you guys agree with this? Any of you actually been injured this way? On the one hand, I can see how it could hurt your knees or ankles if you're fully kneeling in turtle position with the insteps of your feet on the mat and someone pulled you straight backwards, especially if you're not very flexible. But on the other hand, it seems to me that if kneeling to defend that type of back take not only doesn't work, but also puts you at risk of knee injury, then it's a bad defense and you shouldn't do it. I guess in the future when I take the back against a standing opponent and they try to turtle to defend, instead of pulling them backward I'll come up and attack the turtle position from the side. Just thought I'd share this though, since I'm probably not the only one here who hadn't encountered this situation yet.