As far as I know it was just kids playing, my niece ended up getting flipped and landed awkwardly on her arm.
Feel terrible for my sister at the moment as well, seems like everything is piling on her at once. Monday she found out her partner and cheated on her so had to kick him out, yesterday her doctor signed off her work for 2 weeks with stress as she's had headaches and dizzy spells for months and now her daughter breaks her arm and is in so much pain she has to call an ambulance.