both... The hips are loose and the knees are weak. So with his top heaviness he tends to wobble a bit. I mean it's not bad and doesn't affect combined mode because thank god they have a dedicated elbow for arm mode! But if UT used the same arm designs as 99% of the other combiners out there (robot hips and knees being the arm mode elbow joint), Hagen would have been a problem for sure. Oh there are screws on the back of the waist/crotch piece. You have to undo the top half which will then release the bottom half of the crotch (where the swivel is). That will allow you to open up the crotch and get to the hip joints. As for the knees they seem to be pin joints so the only way to tighten them is to add future polish between the joints and let it set. I didn't get to doing him last night so I'll take pics to show how it's done tonight if you are still stuck.