The Truth About EMS (In Bodybuilding)
Electrical Muscle Stimulation: by Charlie Francis
Do they have any real uses? They may be okay for rehabbing athletes, but could bodybuilders benefit from them? We went to Olympic sprinting coach Charlie Francis to find out. What he says may surprise you. Keep in mind, though, that while the beginning of the article applies more to runners, sprinters, football players, etc., later parts have applications for weight lifters and bodybuilders.
The Claims, the Doubts, and the Proof
Increase your strength beyond your natural limits!
Twenty percent maximum strength gains in three weeks!
Break through your training plateau!
Sounds too good to be true, but all this is possible with the proper use of electrical muscle stimulation (EMS). EMS has been used in former Communist Bloc countries for sport training since the early 1950s, but Western countries only became aware of its use in 1973, when Dr. Y. Kots of the Central Institute of Physical Culture in the former USSR presented a paper on EMS at Concordia University in Montreal. There he outlined the tremendous potential for strength enhancement beyond that which was possible by traditional (voluntary) training methods.
His claims raised many eyebrows and considerable effort was expended in an attempt to validate Kots’ claims. Crude studies that pitted EMS-fired muscles against voluntarily contracted muscles (using Cybex machines for measurement) appeared to show that EMS wasn’t as effective as Kots had claimed. However, the design of these studies was flawed due to a poor understanding of how EMS works on the neuromuscular system.
An EMS stimulus fires all the motor neurons in the treated area simultaneously, creating an uncoordinated contraction, which is primarily isometric in nature. Voluntary muscular contractions, on the other hand, roll through the muscle in a wave to generate a coordinated, directed force.
Kots was able to show, using a tensiometric device, that the muscle tension produced in a maximal EMS contraction can be up to 30% higher than a maximal voluntary contraction. This finding was corroborated by independent studies and makes intuitive sense, given the nature of the body’s energy conservation system.
Since individual muscle fibers can be completely exhausted in just a few seconds, the body has adopted several strategies to prolong endurance. Slow twitch (red) fiber is used first in voluntary contractions, as it is energy efficient, though not very powerful. Then only enough strong, but voracious, fast twitch (white) fiber is added to handle the load.
In addition, muscles work their individual fibers in relays, always holding some back from even the most demanding load to maintain a reserve. Therefore, it’s impossible to voluntarily contract all fibers simultaneously. The order of recruitment makes it likely that most of the fibers held in reserve will be white.
EMS works directly on the muscles, bypassing the body’s energy conservation system, thus there’s no limit to the percentage of fiber that can be activated. The EMS stimulus “spills over” from fully contracted fiber to activate remaining fiber (given sufficient current) allowing the athlete to experience a training stimulus that’s unattainable by any other means.
The supra-maximal nature of this exercise enhances the strength to weight ratio by favoring enhanced recruitment over cross-sectional growth and also optimizes fiber splitting and the conversion of intermediate fiber to white fiber, the “Holy Grail” of power training.
Recruitment velocity is the rate at which a muscle fiber can achieve maximum tension, varying from 20 milliseconds for white fiber to 65 milliseconds for red fiber. Recruitment rates vary since red fiber gets a “head start” in voluntary contractions as white fiber is only added in as needed once the load has been determined.
EMS reverses the natural recruitment order, as its nonspecific current flows more easily through the bigger neuron of the white fiber (less resistance) forcing red and intermediate fibers to shorten their recruitment rates in response to white fiber recruitment, which now precedes rather than follows in the contraction.
The reversed recruitment order combined with the positive effects of high intensity make EMS ideal for improving recruitment velocity across all fiber types, a key factor in explosive events.
From Theoretical to Practical
The benefits of EMS have been discussed extensively in theory but the real challenge is the successful incorporation of EMS into a training program. There are four main uses for EMS in sport training. First, for the enhancement of maximum strength; second, as a means of recovery; third, as a rehabilitation tool; and fourth, as a motor learning and muscle recruitment tool.
Maximal Strength Enhancement
EMS is the single most intense strength building method and has the briefest improvement period of all training modalities. Kots’ literature describes a maximum strength gain plateau after twenty-five treatments (which could be administered over four to seven weeks); however, in my experience, most of the benefits available were achieved within ten treatments and strength gains beyond fifteen treatments were negligible. And since ten to fifteen treatments maximize recruitment velocity, it seems logical to work between these numbers.
Strength is the foundation for sport-specific tasks, therefore it must be established early, in both general and specific terms. Generally, strength improvement needs are very high in the early stages of a career and diminish through the years until the athlete fulfills his strength requirements and merely must maintain them (keep in mind that this point applies to non-strength training athletes).
Strength gains on the order of 25% per year, or even higher, may be required in the first few years, though the requirement drops rapidly until top international athletes factor in improvements of 6% per year or less. This leads to the question: why don’t athletes continue to push their strength work to the limit throughout their careers?
High intensity training elements must compete for central nervous system energy. A novice sprinter can’t tax the CNS significantly no matter how hard he tries, but as he improves, the CNS demand rises exponentially, even if the volume of sprinting remains constant. Therefore, the degree of intensification of other factors must be reduced over time if speed is to improve further.
As a result, EMS should be used for strength development as soon as fitness fundamentals are in place, with a diminishing role in routine strength enhancement as the career advances. A quadrennial plan for a top sprinter might include EMS strength building twice per year during years one and two, reducing to once during year three and only if needed in year four.
Special strength requirements, such as secondary hip extension by the hamstring, must be in place early to facilitate the correct technique needed for the development of top speed. These special strengths can be developed even before the athlete is fast enough or skilled enough to develop them through voluntary means. EMS also facilitates the optimal fiber-type ratio, which should be in place early to aid in performance over time.
Incorporation into the Training Plan
EMS strength training should coincide with maximal strength weight lifting. The two modalities are synergistic, though the introduction of EMS must be phased in to allow a smooth progression of the workload. Modern sprint training uses a triple-periodized annual plan, with three maximum strength phases, though only the first two include EMS. The third maximum strength phase is shorter, with a more moderate strength improvement goal.
In our case, the first two maximum strength weightlifting phases lasted seven weeks with a “313” loading system, that is, three weeks of high intensity lifting, followed by one week of medium intensity, followed by another three weeks of high intensity lifting to maximize adaptation.
Apply EMS work during the second and third weeks of each three week high intensity block. As our speed work, followed by lifting, occurred on Monday, Wednesday, and Friday, with speed endurance work on Saturday (Tuesday and Thursday were reserved for low intensity work, with Sunday off), we used EMS on Monday, Wednesday, and Friday, which gave us a total of twelve EMS sessions during the whole max strength phase.
This sequence allowed for the optimal number of EMS sessions in the phase with optimal recovery. (EMS doesn’t require 48 hours for recovery, as it bypasses the central nervous system; however, this schedule optimized the recovery for the other training elements). The volume of explosive power and sprint work must increase seven to ten days after completion of the max strength/EMS phase for the optimal incorporation of the new abilities and to compensate for the drop in CNS stress.
When adding EMS to a program, expect your peak performance up to two weeks later than before, as you’re now tapering from a much higher workload.