Previously we’ve covered research here on Breaking Muscle that indicated electrical muscle stimulation (EMS) can speed recovery. More recently, the first part of what will be a two-part study was performed, focusing on the effects of electromyostimulation on strength enhancement. The second part of the study will deal with the influence of the training regimen and stimulation parameters on EMS training effectiveness.
The first part of this new study was a review of approximately 200 previous studies conducted between 1968 and 2008. The studies were analyzed and 89 trials were selected for inclusion according to certain preconditions: subject age (>35 years old), health (unimpaired), EMS type (percutaneous stimulation), and study duration (>7 days). The trials were classified according to the type of EMS method.1
There were three types of methods of EMS: local EMS methods, whole-body methods, and combination methods. The local EMS method was the stimulation of defined muscle groups with single electrodes. The whole-body EMS method was stimulation and activation of several muscle groups simultaneously through an electrode belt system. The combination method was a combo of local and whole-body.2
Each trial was also classified based on the type of muscle contraction (isometric, dynamic, isokinetic). The study also differentiated between the fitness level of the subjects: untrained, trained, and elite athletes. Next, the most relevant strength parameters for high-performance sports were established. These parameters were maximal strength, speed strength, power, jumping ability, and sprinting ability.3
The results of this study revealed EMS is effective for developing physical performance. After a stimulation period of 3-6 weeks, significant gains were evident in maximal strength (58% for isometric and 79.5% for dynamic), speed strength (37.1% for eccentric isokinetic, 41.3% for concentric isokinetic, 74% for rate of force development, 29% for force impulse, and 19% for Vmax). A significant increase in power was also shown (67%). Developing these parameters increased vertical jump height by as much as 25% (squat jump 21.4%, countermovement jump 19.2% and drop jump 12%), and improved sprint times by as much as 4.8% in both trained and elite athletes.4
This analysis shows untrained, trained, and elite athletes were still able to significantly enhance their level of strength. EMS is a promising alternative to traditional strength training for enhancing performance. There are some distinct advantages that EMS offers, time management being possibly the biggest one. It is safe to hypothesize that EMS use will begin to increase in high-performance sports in the future.5
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