Under the position options window, lower the Blend Weight (the lower it is, the bone structure will be more flexible).
In this same window, set the Coupling to soft, rather than hard.
Branch select the bone's root (by middle clicking), duplicate it, and bring the duplicate down so the duplicate root is between the effector and the null (image a).
image a
image b
image c
Now make the duplicate root the child of the original effector (image b).
You can easily double the length of your chain by branch selecting the original root, duplicating, and parenting the duplicate to the proceeding effector. The more bones you have, the more fluid motion you can achieve (image c).
Now time to test out the chain. Translate the original root in your view; the chain should lag behind based on the blend weight percentage you set.
