Back squat help

Joshua Smeed

I recently have been recovering from chronic hip pain due to over extension of the low back on the squat, deadlift, etc.

 In remedying this, I have relearned my squat mechanics while maintaining a neutral spine.

 Heres the problem, on movements such as front squat, I maintain neutral spine and have no butt wink.

 The problem arises with back squat. As I set the hamstrings back to squat, I maintain a neutral spine. However, in the bottom position, my chest dips, I butt wink, and on the way up I reach into over extension. (despite my best efforts to create torque in the hip and belly tight) 

Any thoughts, useful cues? Heres a short video of my last set today 

[Deleted User]

Have you worked with a coach on rebuilding your squat technique?
Start with air squats.
What is your hip and ankle mobility like?
Squat Quick Test: Is it Tight Ankles or Tight Hips? | Community Video