Moving one leg moves the rest of the armature https://gfycat.com/ContentLividBullmastiff

I did a simple rig following a tutorial but when i want to move its legs using ik, every time the thigh moves, the whole body follows, i already checked the weighs and that is not the problem, any idea what could it be?

P.S: The problem is solved when I un-parent the thighs from the hips, but I cant leave it that way...
Does changing the chain length fix it?
In the Properties Editor->Constraints->IK

https://www.blender.org/manual/rigging/constraints/tracking/ik_solver.html