Specifically superimposed (adding equipment) EMS training is seen as the best of both worlds in terms of EMS along with added weight bearing equipment, very commonly advertised in the fitness industry.
Theoretically it might make sense, but only to individuals who do not know EMS to its fullest scientific extent, forgetting that EMS activates muscles beyond their natural capabilities.
In 2017 a research project was initiated at the ‘Institute of Training Science and Sport Informatics, German Sport University and German Research Center of Elite Sport, Cologne, Germany’ to test the difference in strength improvements between EMS with and without external weight bearing equipment. Twenty athletes were divided into two training groups (10 per group) and were given a series of strength tests. A total of 12 EMS sessions were done in each group respectively and were taken for post testing.
The evidence of the post testing results was quite clear. Both groups improved in all aspects of the tests which were done without one outdoing the other.
The conclusion of this study, even though results were even across both groups tested, spoke very much in favour of EMS training on its own for a variety of different reasons. The first one being weights cannot further muscle intensity or more muscle fibre activation, due to EMS taking a primary role through synchronized muscle recruitment.
Another was “these results give space for speculation of beneficial adaptions of EMS to particularly antagonistic working muscles during movement pattern.”
When weighted equipment appears, so do any risks. When contracting a muscle to its maximum which clearly EMS does, the additional weight bearing contributes in a decreased overall range of movement as well as strain on to various joints in the human body, most notably shoulders, knees and the hip joint.
In turn this can lead to a loss in flexibility as the body is now restricted to one range of movement by this weight when without that weight the body or muscles used for that specific exercise would be free to work within its natural range of movement and even beyond within a safe degree of progression as weeks of training go on. Considering general flexibility levels of most individuals being very poor in today’s world this is definitely not something which should be compromised.
To train someone within the power of EMS (involuntary) contractions and considering how intense these contractions are for the skeletal muscles, there is no reason to try and amplify this process. What is at its maximum is at its maximum and anything further than that, internal physiological alarm bells will start to ring for fear of injury or general bodily harm. For the more conventional minded fitness professional it might take awhile until they dig deep enough to find out such evidence.