What do you guys think about this research comparing stable vs. unstable training surfaces?

http://www.ncbi.nlm.nih.gov/pubmed?db=pubmed&cmd=link&linkname=pubmed_pu...

Nearly all of the research in this search says there is either no statistical difference in effectiveness or "The diminished force output suggests that the overload stresses required for strength training necessitate the inclusion of resistance training on stable surfaces."