Deliberately heading the ball

This sounds similar to an article I just heard about re: heading and the difference between women and men. If I find it, I'll post it.

 

You can find a better version here:

https://www.cbc.ca/news/health/soccer-heading-injury-study-1.4767283

 

I don't recall my Mother-in-Law ever mentioning playing soccer but that would be one explanation!