i don't know if this advice helps or not, eric.
but my buddy tore his knee playing basketball 2 summers ago. when the paramedics arrived, they looked at his shoes and asked him if they were new. in fact, they were new and that was the first time he had worn them.
the paramedic replied, "that's why you broke your knee. . .you should never do any activity with new shoes."
as for my buddy, he now has 2 metal rods in his knee now and regrets every bit of it.
so. . .my advice is to have the right kind of shoes and make sure they are broken in.
as for stretching. . .keep the muscles warm, cold muscles dont stretch. i used to have patella tendinitous (sp?) and daily stretching helps tremendously.
this is what has helped me with my knees:
-knees on floor, sit on ankles, lean back. a couple reps of 30 seconds each time. try not to bounce.
there are probablly tons of info on the web about stretching.
best of luck!
Do not resist chances. . . and there will be one less thing you cannot do -ACG