Hello! I am 54 and generally in great shape and very fit. Last week I spent six hours scrubbing floors in a squat position at least half the time - my knees felt very sore afterwards. Since then my left knee pops without any pain when I walk and straighten it out. I have had this before but it has lasted one or two days; this time it has lingered 8 days. WHat concerns me is that I used to do squats at the gym for two decades until a few years ago and had very strong legs. My knees have been feeling weak even prior to this recent issue. Last month I was surprised that on a 2 mile hike down (2 mile distance and a 1 mile elevation drop) my knees felt very tired and in unusual pain. I have been know to be a long walker but jogging causes me knee pain. I don t know what these two events should tell me: do I need to go back and exercise my legs because of atrophy or is this a sign that I have permanent damage/arthritis and should use caution? Thank you.