I think Flor is referring to when the coach actually sits on the gymnast, and then maybe some of them bounce like that - not good! I don't think that stretching practice of the coach sitting on the gymnast is good at all, for lots of reasons. Other ways are better and good, like stretching from leg kicks and then pulling one leg up, stretching splits from the gymnast kneeling and one leg pulled up, or stretching splits when lying down - just as long as the limits aren't pushed too far to cause damage rather than good - like pulled tendons!
"flexibility training" : http://youtube.com/watch?v=de171R6O0zg&mode=related&search=
not Russian though
coach sitting on gymnast in split
"terribl video of RG training" :
interesting: Alina Kabaeva (famous rhythmic gymnast) with her Russian teammates showing her flexibilty, with someone playing live piano music, to a Japanese journalist.
"Alina training 1999 Aeon Cup" : http://youtube.com/watch?v=qtEVEW6lY8Q