Deadlift and Spinal Extension Issues

Hi Mark,

I'm having two issues that the search function didn't yield much info for, so hopefully you can provide some insight.

When adhering dogmatically to the 5 step set up, I hit a snag around step 4. At this point my hips and shoulders are essentially level and I cannot physically place both my thoracic and lumbar spine into extension simultaneously. I know how to do so, and if I drop my hips a couple inches I can set both my thoracic and lumbar spine into extension without an issue.

As I understand it, hip height on the start of the pull is primarily a function of anthropometry and the position of the bar relative to the foot when in contact with the shins. Are there other factors that could be causing this issue for me, such as poor hamstring flexibility, considering my shins definitely aren't in contact with the bar until step 3, and I'm setting up in front of the bar in step 1 without my knees locked out?

Secondly, when pulling from a position where my spine is in rigid extension, around the point where the bar cross the knee my shoulders come forward into flexion a bit and my thoracic spine therefor also goes into a bit of flexion. Is this simply a failure to maintain extension throughout the entire pull?

Some general info: I'm 6'2" 240lbs, and set up with a stance somewhere in the 8-12 inch apart range with my feet turned out about 30 degrees. My grip has my index finger right on the start of the bar knurling.

Video?

https://youtu.be/UNeuMJKmF08

And one again with the only pair of hard soled flat shoes I can find.

A few things. When you squeeze your back, try and keep your neck/head out of it. Here they are pulling up in the squeeze when we only want your chest/upper back to pull up. Moving the head and neck often makes people sit down (drop their butt) when they squeeze. Even with this your squeeze generally looks fine. Don't worry about how extended your lower back looks after it's extended. This will vary based on flexibility, strength, body fat percentage, etc. Focus on whether or not you see it extending/flattening when you squeeze - it is here. The other point of note is make sure as the bar leave the ground you are pulling it into your shins (keeping it close) and letting your knees get back as the bar rises.