Help with short film from school, 1970s

A film that was shown in school back in late 70s-early 80s about a kid geting bullied and was followed after school walking home. The bully fell and broke his leg I think. I was reminded about this after watching The lottery from the same era.

Any help is appreciated.

Closest i can come is a short i saw Rifftrax do…no bullying, just some older sister talking down to her brother…her and her friend get hurt later on a construction site

http://www.rifftrax.com/danger-keep-out