Now to make this fair, because I don't know any of these kids, I'll talk about a few I personally know. My does does jiu-jitsu and you compete based off of weight and skill. There are two boys there I'm pretty sure are in 5th grade, but maybe in 4th. They are about the same height, I'm guessing 5'5 ish, they are a few inches talked than me (5'1) and they are both 150 pounds. I have no clue how active they are outside of class. One of the boys has a younger sister, she's in 3 or 4th grade and she's about 130. I know how much they weight because I've gone to their tournaments before and I know their weight class. Again I don't know how active she is outside of class.
I would also like to add I was a little chunky too. I didn't get heavy until high school (I actually found my old records saying I was 54 pounds in 5th grade) and by the time I was done with school I was about 120. I know why I was heavy, I made poor eating choices.
But I'm curious about these other kids. How do 5th graders weigh 150? That's how much I weighed after my first pregnancy. I just don't get it.