Sitting straight down with maximum knee bend and minimum trunk lean is my interpretation of a back squat (see video below), but many people look like they’re doing a good morning with minimum knee bend and maximum trunk lean!
Try this next time you squat: use half the weight that you normally do and initiate the movement with your knees going forward (not your hips going back). If you find that you’re leaning too far forward, elevate the heels with a slant board.
Learn more “ass to grass” tips HERE.