I don't think I have seen anyone 'alive' at 5:30 am. Maybe 'cause I'm a coach, but maybe 'cause there is not the possibility to be 'alive' at such an ungodly hour. :shock:
Hmmm.... Sport history reality is this is how the world used to view most sports. Then (at least from my experience) in the 60s, US swimming (at least in N CA) broke the mold and went to two-a-days full time, year around -- 10,000-15,000M/day.
As part of this movement, I'd get up at 4:45 pm, woof down some sort of liquid high energy breakfast, hop in my VW bug; new -- $1950 with sun roof), run around and pick up various fellow swimmers and drive 25 miles to the AM club swim practice. Typically, we'd start with a pair of 1500M, a pair of 800s, followed by some 200Ms (locomotives -- swim each lap faster than the first), and finish with some 50s. This group ended up with some Gold medalists... We'd finish up around 7, home to gobble down a huge 2nd breakfast, HS (plus big lunch), then PM HS team practice (another 6-8000y), then eat some more, study, bed at 8.... Funny thing, getting to sleep was never a problem... Go figure...
The club coach, would show up, give the to do list & sit down and pretend to read the paper while he napped.
In restrospect it was as useful as it seemed fun at the time -- this work ethic became a big part of my college/professional career development and business entrepreneurship.
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If one is looking for a US 2000+ two-a-day soccer variant, for the sake of development and injury reduction, it would seem prudent to look to how many top XC teams practice -- the AM practice is in the pool swimming laps. Only for soccer, one would look water polo (where you don't touch the sides or bottom for 90 minutes). Low injuries, very very high aerobics, excellent all around physical development (legs, torso and arms)... Have you ever treaded water with your belly button and arms above the water for 5 seconds?

That's how you develop true finisher legs...
Sure, many would start out almost drowning, but you'd be surprized how quickly the cream floats to the top given proper instructions. PLUS most water polo tactics translate to soccer. Then in the PM field practice; players wouldn't need any conditioning drills AT ALL, they'd just need skill and modest tactical work. Have you ever seen how hard a water polo ball can be thrown? Imagine that power on throw-ins.
As an aside, with this conditioning background, at some HS mile PE time test, having never run the mile before, I ran a 4:32 as a HS junior -- watching the HS track coach look at his watch when you cross the line -- priceless
OK, so it still might be sensible to let the soccer coach sleep in most of the time -- hire an underpaid water polo/swim coach for the AM practices -- the top WP/swim coaches are truly way out there and early AM practices wouldn't be anything new.
END RESULT -- you'd take the developing US high speed soccer up to another level that would easily challenge the best international teams to keep up with, especially when you start limiting substitutions.... That's when those AM water polo sink or swim practices would easily win the day...