Deadlift back angle problems

[SigurjonG]

https://www.youtube.com/watch?v=5Agmom4xxig

In the deadlift starting position, I find it impossible to get the correct lumbar position. In the video, I follow all the steps - get a good grip, lower shins to the bar, but when the time comes to squeeze the chest as hard up as I can, this is as far as I can go. In the video I am squeezing the chest really really hard as far as I can, but it's not enough and results in a rounded back deadlift. So I was wondering if this is a posture issue, a flexibility issue or some form issue that I'm not noticing?

Thanks in advance.

[Subsistence]

It doesn't look too bad until you actually lift, where you shoot your hips. Also, your video doesn't let us see your feet so it is really hard to tell much of anything from it.

[Nick Delgadillo]

Look at the ground 8 to 12 feet in front of you. Looking up will make it impossible to do this with a flat back. We need to see your feet and the set up. You may be too far from the bar.

[Dastardly]

Need the camera further away to see whats going on.

Can you touch the ground while maintaining a flat back? If you can then deadlifting with a flat back should not be a problem. When you pull here, it is visible that your back loses what little tightness it had, you also fail to lock it out properly.

Lower the weight and see if you can do better.

[Eugene]

You need to planter flex your feet and make your knee angle larger. This will take the slack out of your hamstrings and they will be loaded properly. You are basically using quadriceps instead of hamstrings

I think you are partially doing this because you are too far from the bar.

Your back is not behaving properly either.