"It's OK to fall sometimes. I'm just going to get back up and push even harder. I know there's a lot going on in the world right now and I want everyone to know that whatever we do we've got to do it with love and happiness."
"This was my worst fall yet. My helmet and arm saved my life. This will not stop me. I am going for gold in Tokyo 2021. Stay strong. Stay positive," she said.
Skateboarding legend Tony Hawk replied: "Worst day ever. Hope your surgery went well today."
Sky is a member of Great Britain's national team and remains in contention to represent her country at the Olympics next year when skateboarding makes its debut.
"I want to go to the Olympics," she told the Washington Post last year. "I want to be the youngest one out there and show the girls it doesn't matter how big you are or how small you are. You can do anything."