It could be something to do with the weighting of each constraint. if you don't know how to access it switch your toolbar to the rigging panel click on 'Skin' then click 'Paint Skin Weights' from there you can influence how each joint affects the geometry of the character. you paint the areas that each joint influence to alter how the geometry react to the motion of certain joints. it takes a little while to get used to but it's certainly worth it to save yourself the struggle in the future. anyways good luck hope you figure it out. and this thread is dead.... oh well maybe someone will stumble here and find what they need.