300? Is that supposed to be heavy?
300 lbs
is heavy.
Most people are not even close to being able to bench 200 lbs.
Average Joe will struggle with 150 lbs.
And a lot of women, even women who regularly workout, will struggle with as little as 70-80 lbs in the benchpress.
Don't you meet regular people everyday in your work as a PT?
With that being said, I believe most males could be trained to bench 300 lbs naturally. The exceptions are guys like Mower, ie rare specimens.