A couple things.. I think genetically I don't have real strong joints, but I have messed them up getting in fights and injuring them during weightlifting... but if you are asking as far as tendon OR ligament, etc.. I'm not sure which ones. They ache when I do certain excercises. My left shoulder pops a little during some things and my knees get hurt during squats or leg presses, etc.. you name it... I actually went and had PROLO Therapy a couple months ago (they inject a solution straight into your joints that irritate it and supposidly make your joints rebuild cartilage) and my joints got much better. But still not 100% where I want them. And if I do some juice or IGF or anything, my muscles will obviously get stronger, but I need something to help my joints heal and keep..up.. I take Growth Hormone at the moment to help out too...