Yep that aint' the door closing, it's my knees when I bend down!

I thought I was the biz taking up the sport in my mid 30's and then early last season I'm prepping on the beach for a session thinking "whew looks pretty choppy and gnarley out there - better go a bit easy". Then I see a guy cranking on a bow with a 151 LF board and he's doing super smooth transitions etc like it is a glassy day.
I am just about ready to launch when the guy walks past having taken his helmet off - and he's bl00dy late 50's - 60 yrs old!!! Crikey!!
Made me extract the digit and get amonst the action that day and from there on I can tell ya!
Playing with the orientation of one of my straps has helped my problem knee enormously. Don't assume both of ya stumps are symetrical.

Experiment, load up on the glucosmine and go for it old boy!!