A short while ago I stepped into a 6th grade basketball league coaching situation when the coach became ill.
I was significantly concerned about the fitness of the players. I am not a decent basketball guy by any means, but my father in addition to coaching state track and XC champions in Illinois coached basketball early on at Proviso East, a powerhouse high school program even in the 60's. So I knew something about hoops, including the basics of man to man defense, which is far better from a fundamentals perspective than zone. Young guys don't play well in a Boeheim or John Chaney match-up zone without mastering man to man first. In any event, there was no way for these kids to play man to man - even playing down to the end of the bench, they would be exhausted in two minutes. The coach who became ill warned me.
So we played a lazy zone. It worked out for us except for some parents screaming about playing man defense. I didn't respond - there was no way to play man and if we did every game would have been a 40 point blowout. I was positive and encouraging with the kids - it was 6th grade - and some parents thought I should have yelled at them. Made no sense to me.
I recognize this is anecdotal but not at all like my junior high basketball days - we played man and put on a full court press quite often. We won games because we were in shape. In my day, the Presidential fitness award was highly valued. I worked hard to make sure I made it.