How can I rotate my rig's hip bone without moving the feet?

Question

I want to move my rig's hip bone while keeping the feet in place.

I've been stuck on this for days but I feel like I'm so close to solving this problem.

The feet move up and down when the waist/hip bone is rotated. This is not what I want.

Below is my desired rotation effect (please excuse the lag):

The feet stay still when the hip bone is rotated. This is what I want to achieve.

I hope this wasn't too hard to understand, I'm not good at explaining things.

Here is my .blend file if that helps.

Answer 1

From what I can tell, you want the legs to stretch (slightly) instead of the foot moving. Click on the yellow lower leg bones, and then, under the Bone properties panel, click on Inverse Kinematics (if it's not open), and turn the IK Stretch up to something low, like 0.05. Now, when you move the Waist bone, it should keep the foot on the ground, at the expense of the lower leg bone stretching when the Waist bone goes too high for the foot to stay still. Hope this helps!
Edit: If you want the stretching to be less noticeable, select the upper leg bones as well, and add half the IK Stretch value of the lower leg bones to the upper leg bones.