Correlation is not causation.
The article touches on a much bigger issues, for the most part we do a poor job of assessing risk versus reward in training. The mindset of harderer is betterer, often leads us to making poor training decisions. If training at 50% is good, then 80% must be better and then 110% must be optimal. That's a problem that crosses a lot of athletic activities and hobbies
I don't think any of us should need studies to know that having someone wrench on our necks or choking us out is just a bad idea.