Having done permanent damage to my knees on numerous occasions, I can definitely relate. 3 minutes on an elliptical is about all I can stand before my knees st

Having done permanent damage to my knees on numerous occasions, I can definitely relate. 3 minutes on an elliptical is about all I can stand before my knees start to buckle, though I can easily do MUCH longer than that on bikes or treadmills (as they work the knees and surrounding muscles less directly.) If you're overweight, obviously, getting the weight off of the knees will help them tremendously too. And yes, I don't know how I overlooked that you were already doing other exercise tasks, so my apologies for needlessly repeating what you already knew.