I would also be interested to know if Tim used EMS prior to his WR and if so, how can we tell that EMS is the reason (or one of the reasons) for his improvement and not the many other factors (technical, etc.) that his new coach brought to the table.
Also, I did some research and only found support for using EMS in rehab, recovery, postural realignment in the cases of severe scoliosis, and the prevention of muscle wasting. The only reports I found of its value in strength development were actually for inactive or debilitated individuals. There are several however that had results opposing those of Kots.
To be fair though, there were a couple studies indicating the potential for strength gains in isometric strength (including those references given by Phoenix). Also, Mel Siff's well-respected Super Training suggests that it may be of value for strength development but the references he cites are Russian and perhaps unpublished. Mel tended to often use references to unpublished (non-peer reviewed) studies or Russian studies that can't be found in the U.S. (as is the case with the Kots study). I would assume that these too were gains in isometric strength which then comes back to one of my original questions about the value of EMS because isometric strength gains have been shown to have little relationship with dynamic (eccentric or concentric)strength. In fact, isometric strength gains have been shown to be specific to the particular angles (+/- 15 degrees) that was trained.