Ronda Rousey Gives Pump Up Speech to Kids ... 'Gotta Have Self-Confidence'

Imagine you're about to play a middle school soccer game ... and Ronda Rousey shows up to give the pre-game pump up speech -- pretty cool, right?!

That's exactly what happened in L.A. last week when the UFC superstar surprised a bunch of kids at John Liechty Middle School ... and we're told the kids LOVED it!

TMZ Sports spoke with a rep for the Woodcraft Rangers NVISION program -- which puts together after-school programs for kids -- who tells us Ronda primarily spoke about education and the importance of self-confidence.

It's interesting considering Ronda's self-confidence was down in the dumps after her loss to Holly Holm -- but she realized she couldn't mope forever and seems to have pulled herself out of the rut.

We're told Ronda stayed for the entire soccer game -- cheered on the kids -- and then signed EVERYTHING that the students asked her to sign.