does Doing Yoga / excessive stretching make you more injury prone?

Yoga is more than stretching, in fact many asanas (ie...warrior variations and balance exercises) involve very little stretching. For me, yoga has been invaluable because I had poor flexibility. Others with hupermobility would benefit from more strength and stability.

You're saying yoga improved your flexibility with very little stretching? What do you think was the mechanism for your improved flexibility?

I didn't say that. I stated that there are many asanas that don't focus on "stretching" and I listed a few. The sun salutation variations and repetitions of the downward facing and upward facing dog poses helped me tremendously.

The NYRRC used to have a class led by Thom and Beryl Bender Birch (Thom was as professional runner in the 70s) called "The Hard and the Soft" which was a yoga class that was tailored for runners. I took that class and then a more traditional class that had asanas the OP, if already flexible, probably wouldn't need. The combination was great for me and I ended up teaching yoga to my students.

Hyermobile people don't need to stretch, they need stability; my calves up to my neck are very tight and the downward facing dog is necessary for me, still after 30+ years.

Yoga and running can enhance each other in the right balance. However, I got into power yoga at one point (my wife in an instructor). As started to get more into it and very good at it, my legs got flexible enough they didn't feel right when I ran. I started to lose that tight, controlled spring, I used to have in my legs and I lost speed. I actually stopped running for a couple of years and did only power/vinyasa yoga, getting quite advanced.

Yoga helped me resolve some recurrent running injuries I had (ankle, posterior tibial tendonitis). But eventually, I knew i'd go back to running as soon as I was able, and I did. I was able to jump back into running pretty quick, since the high intensity vinyasa power yoga I did, was very cardio and got the heart up, nicely.

Now I only run again, and haven't done yoga in a couple of years. I do miss how good and head-to-toe fit, I felt when I did it.

I have never been a yoga person but I have strained hamstring more than a few times cold stretching.

Yes of course it could do that. How have you found pilates?

I have no personal experience with yoga, but my PT said she gets a lot of yoga clients and they are even more messed up than the runners she sees.

If your muscles are so tight that there isn't even any bounce in them, then yoga would probably help. If you're already pretty loosey goosey, then it might diminish your running economy.

This quote from David Roche sums it up:
"Now imagine the tension like a trampoline. Too little tension, and you could picture flopping down lazily and having little energy return. Too much tension, and you’d fall on what amounts to a brick wall. Each athlete will likely have an optimal level for injury risk and performance that varies a ton by the person and over time."

The other factor is that yoga helps tap into a more natural range of motion which runners might not get just from running; I know 2:09 marathoner Stephen Scullion swears by yoga. Also a lot of the Kenyan/Ethiopian running drills tend to end with multiple static poses that are pretty much yoga by any other name.

Agreed.

Key word in your post is 'excessive'. I have found that if I over-roll out or spend way more time stretching than usual, I lose some "spring" in my stride. I know this isn't quantifiable, but some natural tension can be okay.

I always wish I enjoyed/was good at yoga. In moderation, I can't imagine the benefits. Core, stability, strength, stretching, breathing etc

Yoga is much more than stretching. It strengthens your legs, core and arms. Practicing yoga regularly both the vinyasa and yin asanas will only help your running. They complement each other.

That’s because they’re not doing the poses properly and not in alignment and the instructor isn’t adjusting them.

But does she mean physically or mentally?

I don't doubt that. She mentioned that the problems were frequently in the shoulder region, something about them getting overstretched.

Not overstretched. Their shoulders are probably not strong enough to handle the poses they are attempting and/or they aren't doing them properly. As in any sport or physical activity there will be injuries. The alignment especially in chatarunga is critical. Same with shoulder and head stands. The PT has no clue what is happening in class, he/she only see the result when the patient comes in

Is that a joke?

What does Christianity have to do with the question? Are you going to start listing sex positions Christians should avoid also? I am a little thrown off by your invocation of religion into a question about stretching your f&$*#&# muscles.

I think what they may be referring to is "whole" of yoga practice. (which is completely bogus btw) Yoga is not just a physical exercise, it embodies mind and spirit as well if practiced seriously. The mindful/meditation and spiritual practices, which also include various mantras are based on Hinduism. Very likely that certain Christian groups would frown on that

So some generic "sky force" doesn't believe in yoga?