Attached to this blog article is a video breakdown of one of our powerlifters (Molly) and a set of her deadlifts from a recent training session. This is actually the 2nd of 3 sets of 3 reps for her at a very high percentage of her max deadlift - with this actually being a volume PR for her. What I will work with her on is explained in the video, which is her start position and one of the biggest mistakes I see with lifters in the sumo deadlift.
To try and put into words what this problem that exists is, we can see a lowering of the hips "too low" on the start/setup of the deadlift. This occurs in both the conventional and sumo deadlift but I would argue that I see it more often in the sumo. What we see is that the hips are dropped low as the chest is pulled upright. But as the pull is initiated, the hips rise without the bar being separated from the floor. This is happening as the body is trying to move into its most mechanically advantageous position in order to generate the most force possible. But all this hip motion while pulling without the bar moving is wasted energy!
So how to adjust? The cues/coaching I like to give in this instance is to try and keep the hips higher in the setup and instead try to pull the chest up taller instead of the hips lower. Bending the bar as much as possible from the very beginning of your setup and possibly pulling the bar off the floor with just your setup are 2 other ways of wording this setup cue is. If you video yourself and watch it in slow motion, the correct position of your starting position is whatever position your body is in when the bar leaves the floor. That is the moment that you can pause the video and assess your positioning there and work on working on your positioning. I hope this information can help you clean up your deadlift start and you see some bigger deadlifts come from this setup change. Less "wasted motion and energy" at the start will give you more energy to finish bigger pulls!