From my own experience, not really Not for speed anyway.
I find that kids (14yo and under) respond way better to nothing longer than a 150 for Spec. Endurance and 15-20m for speed. That’s how I train my daughters and some other youth athletes. And they keep improving every year while everyone on their old track club is still running the same times from several years ago. My oldest (12yo) can go all the way up to a 800m when she does her pentathalon and all she does is short stuff. Although, she’s pretty active and gets fit from other things.
I see. Im 16, but I have a problem with slowing down too much in the 100 and also 200 endurance simply seems weak vs. guys my speed, so running 250-300m good idea? for spec. end. I