So, what's the deal with stretching after warming up but before training?
I had always been under the strong impression that the ideal was to warm up well then in turn hold each relevant muscle in a relatively stretched stretch for 10-15 seconds (3 times each?), then train.

Some dude who is doing his 2 year masters in PE or something told me the other day that that's not ideal on a small muscle like your forearms because stretching causes tearing or something, and that it is for more of an issue for small muscles.

But if I don't stretch, I feel like I am going to shred my tendons.

I feel like I don't understand the situation. Please tell me what to do to maximize being awesome at climbing hard while also being totally rad at not getting injured.

Many thanks.

Sounds like your warm-up isn't warming up those particular muscles. Most exercises don't limber up my hands/forearms; I have to climb easy, then moderate, and usually one route close to my limit to warm up completely. But then I'm old. I think at some point my entire workout will consist of warming up and from that point on I'll only get weaker.

Blah, stretching is useless IMO. I have climbed over 4,000 pitches in my life and I haven’t stretched before any of them yet I have never been injured from not doing so. When I am required warm up for military activities I find it only consumes needed energy and reduces my performance in the task to come. My warm up routes are my project routes. If I start on something easier I lose much needed energy that I need on my projects and thus my performance is decreased. Overall the best “stretch” or “warm up” is your normal climbing grade. Just jump right into it. day.

So, what's the deal with stretching after warming up but before training?
I had always been under the strong impression that the ideal was to warm up well then in turn hold each relevant muscle in a relatively stretched stretch for 10-15 seconds (3 times each?), then train.

Some dude who is doing his 2 year masters in PE or something told me the other day that that's not ideal on a small muscle like your forearms because stretching causes tearing or something, and that it is for more of an issue for small muscles.

But if I don't stretch, I feel like I am going to shred my tendons.

I feel like I don't understand the situation. Please tell me what to do to maximize being awesome at climbing hard while also being totally rad at not getting injured.

Many thanks.

You are getting mixed results mostly because older, traditional training methods are being slowly supplanted by more science-based methods.

First, why do you want to stretch? Because you like the way it feels? Fine, go for it. But a search on Google Scholar including the terms "stretching" and "injury prevention", should convince you that there exists NO evidence that stretching has any effect at all on preventing injuries. The eveidence is just non-existant. Perhaps a better study needs to be done, but so far, it appears stretching does not prevent injuries.

Everyone is different. Some people need a warm up, cool down and stretching. Some people can leap out of bad and crank hard with no ill effects.
I have a friend who can jump on his bike and hammer while I need 20 minutes of warming up before my body is reday to sustain a hard effort. Likewise, I need a good warm up and stretch before I can climb hard. If I don't warm up properly I'll burn out really quickly. For me, stretching seems to be very benificial.

I agree, everyone is different.

However, if a significant number of people benefit from stretching (such that it reduces the chance of injury), then it would show up in the data for a properly randomized study.

Also, "warming up", is one thing. "Stretching", is something else.

There actually is some research showing sustained stretching decreasing muscle power.