V-up critique?

I think my back is far too rounded and I'm not lifting my body high enough. 

Here's a link to the video file: https://www.dropbox.com/s/okv6m82qu3ldsc7/Movie on 10-16-17 at 6.49 PM.mov?dl=0

Thank you. 

Hi Oleg, actually your it is a technique problem. you need to begin the movement from the shoulder and after the leg. if not your center of gravity will be on the sternum rather than the hips and you have no chances to lift the upper body.