Exactly. Early morning routine becomes getting kids out of bed, dressed, fed, and off to school. If you're getting up before THAT to do your own things, it would need to be really early.

Casey Neistat has two kids and gets up at 4am to exercise before taking care of them. This video goes over his time management technique: https://www.youtube.com/watch?v=C-Cvl3_CH2A

By his own reckoning he sleeps for under 5 hours every day. Maybe he's one of the vanishing few who can get by on that amount of sleep (you are not though, so don't try to emulate him), or maybe he's not listing naps he takes throughout the day, or maybe he's just setting himself up for a lifetime of health consequences from prolonged sleep deprivation.

Whichever it is, it's not exactly the sort of routine one should take too much inspiration from for one's own life.

One of the people in TFA gets up at 2-3am on Tu/W/Th... O_O

Yup - life becomes more complicated with kids especially. You get a schedule which works for a year or two, then school start times switch. Then your partner has to leave at 5.30am a couple of days for work shifts and you're on duty those days!

Currently managing most weeks Aikido twice a week 6:30-8:00 (I teach), and 1-3 runs per week with a buddy on a flexible schedule 6:45 - 7:30 start depending on getting kids off and being able to work at home a couple of days a week.

I first established this habit back when I was married, so I can attest that it’s compatible with at least some romantic relationships. Can’t speak to the problem of balancing discretionary time and parental responsibilities, other than to say “Good luck!”

It obviously depends on the kid, but they tend to sleep longer than adults anyways. Our 1 year olds sleep around 11-13 hours overnight. Our 4 year old sleeps around 11 hours overnight.