This is false, even cyclists who think they pull up and pull back do not, and it is less efficient to do so. However it is a VERY common misconception that you should do this.
Anyway, I can't find any of these so-called studies that admits to knowing what a sprinter is let alone a green jersey, so I'm going to keep my eye out for less flawed studies.
In fact, get me one by a team medic or physiologist, and then we can talk. Until then it's nerds in coats coatsplaining things to people actually doing the work.