i think you're bending your knees at the proper time but the problem as i see it is that you're not bending them enough! watch your last video again and take note of the position of your butt at the top of the movement and then watch how little it changes as the bar travels down to the floor again. on some reps it barely gets any lower than it was at the top of the rep! it seems you're starting the trip back to floor ok but when you bend your knees it aint enough and so your forced to pivot at your hips further to get the bar back to the floor causing your torso to reach an almost parallel position. to my mind when you're done with a rep your body should be back in the starting position ready to set the back for the next rep but you end up having to get yourself down into position after you've completed the rep and i think this is one of the reasons no two of your reps look very much alike. this is why i will strongly advise again that you not worry about loading the bar until you are able to get 5 good clean consistent reps in a set. Dont be in a rush with deads, they're one of the best but hardest exercises to even get just a decent form on nevermind to master.

i hope some of the other more knowledgable people will chime in and either verify what i've said here or point out the errors in my thinking because hey i wanna make sure i'm doing them right too!

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