How to lock feet to the ground (Animation help)

[YammiJammi]

Hey, I was hoping someone could help me out. I've started learning how to animate in blender, and I was wondering if there was a way to lock the feet to the ground and then unlocking them whenever I wanted to.

 

For example, my sim is pole dancing, they will walk around the pole and then climb up.

 

Any tips or tricks would be most appreciated ?