How articulated and yet so precise.
I guess the programmer programed somthing like this:
7 stars 55 % chance of injury each match/training pass
6 stars 40 % chance of injury each match/training pass
5 stars 20 % chance of injury each match/training pass
4 stars 5 % chance of injury each match/training pass
3 stars 5 % chance of injury each match/training pass
'this is not documented'