ACL injury advice? Mid January I injured my knee playing football.?

The hospital have confirmed I have partially torn my ACL.I have been given a hinged knee support with a restriction of 0-60 degrees.I have no pain whilst walking but cannot bend my knee past 90 degrees.My question is: Would I damage my knee further if I was to cycle?I believe that i really need to start exercising it as i'm losing muscle.Any suggestions?