Neck and Spine distort when I move the hip bone too much.

I’m doing a tutorial here: As part of the walk cycle, I’m supposed to move his hip bone up. When I do it past a certain point, the neck and spine bone contort. Is there an easy fix for this situation? I know (following the tutorial) earlier, I segmented neck and spine bones. But in the tutorial, the hip bone is moved without the neck and spine bending out of shape so much.

Screen shots:
Before the spine and neck bone distort:

After I move the hip bone to where I think it should be for the walk cycle:

Blend file:

It looks like your head is not moving at all, and the spine and neck are compressing between the hips and the head. Seems as if the head should move up along with the hips. Check parenting to make sure something is moving the head automatically in this situation. Could your head be IK by any chance?

I checked. The head is parented to the neck, the neck is parented to the chest, the chest is parented to the spine, and the spine is parented to the hips. No IK on the head. Anyway, I rotated the chest bone, and now there is better alignment. Still, I wonder why that problem didn’t arise in the tutorial. As a beginner, I must have missed something. Thanks for taking the time to respond.