I'd be curious to know if the staff is claiming any benefits to early morning workouts beyond the old school line of – 'if we get em out of bed early, they can't get in trouble the night before.' I'm HOPING that Duval and team are seeing some kind of correlation with practice/lifting and time of day.
That being said, the emerging science around sleep is pretty clear – most people need between 7-9 hours. and you've got to be diligent about it to achieve the benefits. But the bottom line is that sleep has a direct correlation (causality remains to be proven) with virtually every aspect of the brain and the cardiometabolic system. To paraphrase one expert – the less you sleep, the faster you die.
So unless there's some scientific basis for it, I'm suspicious that Frost may be going a little old school needlessly. Because as you pointed out, sleep is pretty easy to track these days, there's all sorts of ways to do it. But the kid has to be responsible enough to be "lights out" at 9PM in order to get enough sleep for 6AM practice. And to make it even more effective, that same kid either needs to put the screens away by 7PM, or put on his blue-blocking glasses for the last two hours of the day.
Most NBA and MLB teams are running their in-season schedule exactly counter to what Nebraska is doing these days. When the Lakers team plane lands at 2AM, they'll cancel the scheduled shoot-around – or they'll push it back to the afternoon.