Thanks to all the people who sent me posts regarding knee pain.
I'm trying a few of the suggestions and today I had a pain free 12 mile hilly ride!!!! I could actually dismount and walk right off without a hitch..literally!
What did I do?
Dropped the stirrup on the downhills. Stopped gripping with my knees. Became aware of how hard I was bracing with my knees on downhills and kept my legs free swinging with the horse's motion, yet gently touching her barrel. Before my knees where behind and bent. I also ordered a pair of Trail Tech stirrups. I have a ride this weekend so I doubt I'll use the stirrups...too soon to try something knew maybe.
Anyway now I am ready to move up to a 50 after over a year of LD's.
