There isn't a rule about skate height it's just expected that you would never do some shit like that, people get upended all the fucking time during hip-checks and skates can easily swing out higher than head height when you're somersaulting through the air. This definitely murder 1
I'm surprised there aren't more major injuries in the sport. The speed, collisions, etc.
I had a few friends in grade school (pre-teen years) who played competitively for years. They were always exhausted because of the early-morning hours on weekdays. Practices would be at 5:30 or 6am once or twice weekly, as ice time was at a premium ($), and they'd be falling asleep in class a few hours later. Shit ... I had some basketball practices at 7am in junior high and I always felt like shit getting myself out the door by 6am as a teenager, lol.
The rest of us mostly played soccer, basketball, and / or football. Practices for those were immediately after school, or mid-evening for our league teams.