I have had the Bodyblade for many years now, along with the " smaller pair", which I believe are called cardio blades. There was no " breakin period" on the none of thesr 3 blades. I have no idea what you(the OP) even mean when you say," it took awhile to get loosened up".
My Bodyblade today is the same as the 1st time I used it, as are the smaller yellow pair. It does take some longer than others to get the rhymn that works the best for them. My wife gave up several times before she became a fan of this piece of equipment. I have never seen nor used the Walmart, or any of the other knockoff versions of the Bodyblade, and have no reason to do so, unless someone I knows tells me they have one and want me to try it.
I can only say what the Bodyblade does and how to increase or decrease the amount of effort it takes to use it. No "breakin or loosening up period" for the ones I have owned and and used for many years.
hckynut(john)