EMS, The full English name is Electric Muscle Stimulation, or NMES, NeuromuscularElectrical Stimulation.
Its principle is to simulate the release of bioelectric signals from the brain by wearing specially designed conductive training clothes, which stimulate muscle neurons in the form of electrical pulses and trigger muscle contractions.
In the past two years, this training method has been highly sought after by fitness studios in China, who have begun to purchase or rent EMS equipment to try it out for their clients. EMS coaches claim that this training method is efficient and time-saving, achieving a 2-hour training effect in just 20 minutes, far exceeding ordinary training methods. I have also seen many experienced enthusiasts believe that this training method is a 'IQ tax'. Some EMS supporters also believe that this training equipment can overturn existing fitness methods and become a standard equipment in venues like other fitness equipment.
At present, research on muscle electrical stimulation mainly focuses on the field of rehabilitation, with less involvement in strength training. The following viewpoint is mainly selected from a literature review paper on muscle electrical stimulation training to analyze whether this training method is so magical.
The relationship between "EMS" and "power output" presents a sigmoid pattern.
Generally speaking, the frequency of electrical stimulation must be close to 70-80Hz for the effect of strength improvement to be more significant, and the effect of muscle hypertrophy to be more pronounced at 45-75Hz.
Moreover, this effect also needs to consider muscle fiber types (Type I, IIa, IIb), as different types of muscles have different characteristics and suitable stimulation frequencies. The stimulation frequency must be higher than the physiological emission frequency in order to have a more ideal power output.
In addition, many studies have confirmed that the cross-sectional growth of muscles after EMS training is mainly concentrated in type 1 muscle fibers (slow muscle, endurance), while the cross-sectional area of type 2 muscle fibers (fast muscle, strength) decreases, and type 2b shifts to type 2a. This means that EMS may be more focused on endurance training and may not be as effective as self training for muscle hypertrophy and strength.
We all know that muscles increase protein synthesis and muscle volume due to resistance training, and EMS training also has the effect of causing muscle hypertrophy.
Studies on elderly patients with diabetes have confirmed that using EMS (60Hz, 3s continuous/3s intermittent) for 60 minutes can increase the synthesis of muscle protein. However, the protein synthesis rate of the EMS group is 30% less than that of the 30 minute independent training group, and the intensity of the independent training group is 45% -75% of 1 rm.
Another study measured the concentration of serum growth hormone (which is closely related to muscle growth) and divided it into an autonomous muscle contraction group and an EMS group.
When controlling for the same amount of force generated between the two groups, it was found that the concentration of serum growth hormone in the EMS group was higher than that in the voluntary contraction group.
EMS is still a good training method for preventing muscle atrophy, rehabilitation of sports injuries, improving muscle endurance, and helping with weight loss. However, in terms of muscle hypertrophy, strength, and explosiveness, it may not be as effective as self training, let alone expecting its training effect to be several times better than self training.
