I was with a company that did research run by Garhammer in LA in 1981 treating the weaker leg in conjunction with several training regimes.
In fact, this was the period when I worked with John Smith and John arranged for the test subjects. The study was flawed IMO because Garhammer ignored the recommendation to allow a 10 day consolidation period after the last EMS session for a final comparison.
Because there was no consolidation from a higher workload, the tested side showed greater strength but slower peak velocity, as any coach worth his salt would expect!