;( Hi Cathe! For the past 6 months to a year I have been noticing when I stand on my left knee from a sitting position there is a dull-cathcing kind of pain/ache. Of course I have done years, 18 to be exact, of stepping and squats/lunging to your workouts. Any suggestions pointers on what to do to alleviate the dull pain? Have you ever had arthritis of the knees?