Is it safe and effective to bend knees during manual stretches

I am a newbie but have found that manual stretches become far more intense when bending down with my body or leaning forward or squatting down. Does anyone else utilize these maneuvers while stretching? Is this a safe and effective way to increase the intensity of simple manual stretches? Any input or advice would be greatly appreciated.

Yes, it is absolutely fine.

Thanks gymnast, is this something you do to? I’ve been reading a lot of posts lately but I have not come across anyone discussing bending down or leaning forward as potential ways to intensify a stretch? Is it uncommon?

I do not simply because i’de rather stand up and relax while stretching as opposed to holding a squat position. If you want to intensify your stretching the first thing i’de do is find out your "LOSS OF TUGBACK" look up bibs LOT theory.
Then you can look into more intense stretches like "A stretches" "LDP stretch" and other stretches like bends and so forth.

Check out these two threads:

The 5-minute routine

2-inch Growth Comparative Pictures