I think sports are the principal reasons classes start so early in high school in the u.s. i recall shuddering under heavy rainfall in the early a.m. hours waiting for a bus to pick me up, barely conscious, staggering into a "homeroom". By the time I woke up, it was time to go home. Most kids stayed after for 6 or 7 hours practicing sports they'd never have the slightest chance of competing in beyond high school.