Competitive highschool sports often practice for several hours a day. It's not really a serious sport if you're only going to practice a few hours a week, is it? Maybe badminton club practices an hour on thursdays, but the swim team is going to be swimming for at least two hours every weekday for much of the year. Sometimes we had practice in the morning before school as well, two practice sessions in a day. There were days I spent almost as much time in the water as I did in a classroom.

But to the point raised in comments above, most boys were not participating in sports. Maybe 1 in 4 were at my school.