Not only are boys more interested in events that have to do with competition

but they fare better than the girls

It’s not a sexist trope

Pick one.

Girls can be just as interested in competition. Like have you ever been around athletic girls? Girls can be competitive af. This concept is definitely a sexist trope as it does not have a base in reality and manages to generalize little children’s personalities.

Admittedly men do usually do a bit better at physical activity than women (but there are still lots of really good female athletes out there). That being said this is presumably with younger kids. Boys and girls are more similar before puberty hits so depending on the age range the boys and girls would be more equal in physical strength.