Kneeling for yard work is NOT in my cards, for sure. But I actually did a "fast" command in obedience with my dog the other day and lasted for more than 10 steps. I was pretty proud of that even if I was the only one who noticed it. My gut would say that kneeling on the knee for any extended amount of time might tend to "wear" it abnormally. Not quite sure why I think that, but I certainly would never want to "break" it.......ever. Of course, rainy days really do get to me. My PT said I will be a "walking barometer" for years to come.......ugh.