Electricity and Neuromuscular Physiology

Deeper look into how Science of electricity and Science of motoneuron activation works together.

WB-EMS Combines Muscles, Nerves, Electricity, Into A Training System Unparalleled in The Fitness Industry

What you need to know to be healthy fit and vital for a long time.

Muscles need your constant attention, because the way you treat them daily determines whether they will wither or grow.

  • Your muscle system is so important to your health
  • Research that studies exercise report that exercise is critically important for your wellbeing
  • Exercise is a great way to keep fit for an active lifestyle
  • Exercise is a great way to help reduce the stress of a full lifestyle
  • A strong muscle system will keep you active well into your later years
  • People fear osteoporosis and osteopenia but are unaware that sarcopenia is a greater threat
  • Understanding that your muscular health directly impacts your ability to live a full life at all the stages of your life
  • Understanding a few basics of how your muscles work to get you fit is important lifesaving skill
  • Exercise - increases muscular tone - eats fat.

Muscle works this way

I want to walk you through a few vital concepts that are the basis for you getting fit, staying healthy throughout your life and banishing forever weight gain through increased accumulation of fat. I have found that it is so much more effective to teach people how their body works instead of giving them a list of exercises.  

Muscle anatomy
A skeletal muscle is constructed like a sturdy piece of rope.



Muscles are made up of fibers within fibers and layers within layers down the scale, from the bumps and lumps you see under the skin all the way down to the microscopic cell level. Obviously, muscle tissue contracts to function. At the cell level is where the magic of contraction takes place.

Thousands of tiny parallel threads called myofibrils or muscle fibers are packed together to form muscle. The smallest cell of muscle is called a sarcomere in which even smaller protein filaments called actin and myosin strands shorten against each other. Their contraction shortens the muscle cell. It is called a sliding filament mechanism. A single muscle fiber from a biceps muscle may contain 100,000 sarcomeres. As more muscle cells contract, they generate enough force to move an arm or leg or the entire body if enough cells are contracting.

You are three times as strong as you think.

But you are not using all your muscle fibers at the same time. There is a significant number of muscle fibers that are not contracting when you are lifting, running, doing muscle effort, even when generating the maximum force possible. As the muscle fibers that are actively contracting fatigue, they relax, rest and restore and other fibers within that muscle take over the contraction. As they fatigue, yet more fibers are recruited while they restore. Science’s best estimate says that you are using only a third of the muscle effort you can generate most of the time. When one set fatigues and resets, other strands shorten. With exercise they can shorten longer with less fatigue, but the muscle tissue will always go through this cycle.

Remember: 1/3 of muscle fiber contract at a time as it will become important in later discussion.

Different kinds of contraction slow and fast

Next, the muscular concept important for you to know about is that different muscles have different speed of contraction. I think most people have heard of ‘fast twitch’ and slow twitch’ muscles. This means that skeletal muscle fibers can be categorized according to their speed of contraction and their resistance to fatigue. The three basic types include:

  1. Slow twitch oxidative (type I)muscle fibers,
  2. Fast-twitch oxidative-glycolytic (Type IIA)muscle fibers, and
  3. Fast-twitch glycolytic (Type IIX).

Fast-twitch (type II) fibers develop muscle tension two to three times faster than slow-twitch (type I) fibers, but it comes at a huge outlay of energy that is difficult to replace. It is much simpler to engage slow twitch muscles as they do not expend large amounts of energy and they can work (contract) for long periods without fatigue. However, this also comes at a high price, namely dormancy and atrophy of fast twitch muscles causing huge negative repercussions to your health if you don’t move much over long periods of time. 

There are simple explanations for the things we do in our lifestyle that are directly responsive to our reliance on slow twitch muscles. Take, for instance, the gas pedal of your car. You can push that pedal down for hours without fatigue. You are using the Soleus muscle in the calf that is predominantly slow twitch and fatigue resistant. If we had to lift the gas pedal up, raising the toes toward your kneecap, we wouldn’t be able to drive longer than a few minutes before the muscle in the front of the shin (Anterior Tibialis, a fast twitch muscle) would fatigue with painful spasms. (Try tapping your toes to your favorite song and see how long it is before your shin starts cramping. I’ll bet it’s less than a minute.)

The forward slump of sitting at a desk for long periods is the result of engaging endurance, fatigue resistant muscles in your neck, shoulders and back while turning off muscles responsible for graceful movement in your belly, butt and legs. This muscular amnesia is responsible for that shuffling, penguin-like walk you see from desk sitters and video game players and now more prevalent in children slouched over their phones. These abnormal postures also morph the muscle fiber types into a greater predominance of slow twitch fibers. Sedentary postures from static low activity occupations and endeavors decondition active movement muscles and devitalize us and age us.

It seems from research that women have a higher ratio of slow twitch to fast twitch compared to men. It may explain why women can be still and quiet longer than men and it also could be an explanation why women are drawn to cardio or aerobic workouts more than fast explosive workouts.

Regardless, the fact is there are certain muscle types that fire differently than other types. Research points to seven muscle fiber types but the three dominant types are listed above and repeated here:

  • Slow contracting: that has lots of oxygen reserves;
  • Intermediate fibers: that are faster with oxygen reserves but not as large a reserve than the slow fibers;
  • fast contracting fibers: with little oxygen reserves that does large work but for short times before exhaustion.

When people don’t exercise, get deconditioned, and replace muscle with fat, there is a conversion of muscle type. There is a shift from slow to fast muscle fiber type. Decreased use of skeletal muscle can lead to a conversion of muscle fiber types in the slow to fast direction. That is because fast muscle fiber has an easier path to atrophy and re-absorption by the body.  This leads to a preponderance of slow fiber left in muscle tissue that forces the slow shuffle walk, slumped posture and the stiff crampy feeling in the remaining muscle tissue.

Now through training, it has been shown that muscle fibers can adapt to changing demands by changing size or fiber type composition. Muscle fibers not only change in size in response to demands, but they can also convert from one type to another.

This muscular plasticity in contractile and metabolic properties in response to stimuli (e.g., training and rehabilitation) allows for adaptation to different functional demands and is one of the special effects of WB-EMS exercise because the frequency of firing rates of the neuron also alters the muscle fiber type. No need to focus on fast or slow fatigue training protocols with WB-EMS you are recruiting all fibers simultaneously slow and fast and maximize the workout… in shorter time.

Remember: muscle fiber has three different speeds of contraction and lengths of fatigue resistance as it will become important in later discussion.

Muscle meet Nerve

Contractions of muscle fiber will NEVER happen unless the muscle is triggered by an electric signal from the motor nerve attached to that muscle fiber.

Muscle will only contract when stimulated by a motor neuron generating an electrical impulse. A motor neuron can innervate between three and several thousand muscle fibers. A nerve and its attached muscle fibers is called a motor unit. This is the true functional unit of the neuromuscular system.

Muscle tissue is a voracious energy hog. Each muscle is hooked up with its own personal nerve, to stimulate contraction and its own artery and vein to keep it well feed with all the blood oxygen and nutrients it needs to operate.

Nerves activate muscle this way. The initiation of muscle effort (contraction) is a neurologic process and an electric phenomenon. A nerve impulse to voluntary muscle fiber starts as a mental command from the brain: “Lift this” or “Duck!” The nerve impulse travels down the strands of the motor nerve until it arrives at the end of the nerve just across a tiny gap from the muscle cell. Where the nerve ends at the muscle is called a neuromotor junction. The tiny spacing between the nerve and muscle is called a synapse. At the nerve side, the impulse triggers the substance acetylcholine which is a neurotransmitter. Acetylcholine crosses the synaptic space and signals the muscle to function and muscles respond. This point is critical to understand how EMS works naturally with your body to enhance effective exercise.

Muscles act with a learned response by performing that activity hundreds if not thousands of repetitions. It is a physiological dance, with nerves firing and muscles responding to commands. Thus, exercise has both nerve and muscle components that must be addressed in an optimum workout.

This myoneural (muscle/nerve) connection is needed to make muscles contract. The bigger the challenge becomes, the bigger the brain’s signal grows, and the more motor units are recruited to help you achieve your task.  

Remember: muscle fiber can only contract when and only when a motor nerve sends an electrical command as it will become important in later discussion.

Muscle Recruitment

Let’s say you want to lift your coffee cup; you reach over, hardly without looking or thinking about it and pick it up, like you have done a thousand times before. You are relying on slow twitch muscle fibers that have efficiency and economy; not much effort. But just don’t think that it is muscular effort alone, because as you remember, nerves must fire first before any muscle will contract and the motion is controlled by nerve commands, which is why you pick up the coffee cup and not mistakenly the saltshaker.

What would happen if that cup didn’t weigh just ounces, but weighed 15 pounds or 50 pounds? You could not carelessly reach over, lift your mug and drink your coffee. Mentally, your attention is focused on the task at hand, the brain summons muscle effort through its network of motor nerves. Just like any heavier lift, your attention would be focused on lifting, you would shift your body position just in case you needed more muscular effort and you would signal your whole body to ‘lift’. More than just slow twitch muscle would be recruited. Most of the muscle fibers of all types would be contracting in your hand, arm, shoulder, back and legs. Like the turbo boost in racing cars, your fast twitch muscle fire with large expenditure of energy that is slow to replace limiting how many times the fast twitch muscles can fire before they fatigue.

And the potential of being injured lifting 50 pounds is much greater than being injured lifting that cuppa joe.

So, you see, in voluntary muscle contractions, the muscle tension is proportional to the electrical activity or the nerve signal that the muscle receives.

A scientist in the late 1960s, named Henneman discovered that the size of nerves signaling muscles was significant to the order in which muscles would fire in sequence. 

Henneman’s size principle states that muscle fibers are recruited slow to fast using more energy as effort increases.

The larger the nerve diameter to a muscle, the faster the conduction velocity of the impulse and the stronger the muscular contraction produced.

Henneman’s size principle states that muscle fibers are recruited slow to fast using more energy as effort increases.

Slow twitch muscles have smaller diameter nerves and are normally recruited first. As the demand on the muscle increases, the larger nerves begin to stimulate the fast twitch muscles in conventional (i.e. weight training, running) workouts. Thus, to recruit more muscle fiber, the exercise must get harder by lifting heavier weight, running faster and/or longer. There is a larger time period to work up to higher demand safely, as muscle must strengthen enough to avoid straining joints and other injury prone connective tissue.

When EMS is utilized, small gentle current passes through the pads in the suit to stimulate the neuromotor junction. But the size principle does not apply to EMS signaling. The larger nerves to fast twitch muscles are stimulated at the same time as smaller nerves to slow twitch muscles. Thus, contraction of ALL muscle fibers initiates as soon as EMS training begins. There is no need to lift heavier and heavier weights to get fast twitch muscles involved in the training. Thus, EMS training works on all muscle fiber to condition them to be fitter, with all the benefits of a hard, rigorous workout without having to lift potentially dangerous amounts of weight.

Remember: muscle fiber responds to demand of the exertion required and muscle contracts slow twitch to fast twitch in conventional applications. EMS training avoids potential injurious situations and recruits all muscle fibers at once, shortening the time to get a great full workout as it will become important in later discussion.

How Exercise Works

The point of exercise effort is to get stronger, fitter and/or get bigger muscles. And lose fat. And feel good. All the above.

What happens in the body to get that to occur?

Muscle demand – to get stronger, muscle needs to work. Without work, muscle is converted into energy and reabsorbed by body. Hormone levels and metabolism plays an important role. With youthful levels, it is easier to build muscle and young muscle resists breakdown. As we age, it is harder to build muscle due to lower hormonal levels, reduced metabolism and stiffer connective tissue which leads to tissue breakdown with high levels of use = injuries. But to build and work, muscle needs to be activated.

When muscle is exposed to work or stress, it undergoes microscopic damage, which when it is exercise, is a good thing. In response to the stress, the injured cells release inflammatory molecules called cytokines that activate the immune system to repair the damage. This is when the muscle building magic happens. The greater the injury to the muscle tissue, the more your body will need to repair itself. The resulting cycle of damage and repair eventually makes muscle bigger and stronger as they adapt to progressively greater demands.

Muscle responds to use, conversely, it also responds to disuse.  High usage means muscle grows larger and or more efficient with better blood flow to bring nutrients and remove waste products of muscle action. Disuse brings all the negatives of the above.

However, every day activities are not enough to stimulate this cycle to build more strength and fitness. Household chores and rush hour driving to a desk job does not stimulate new muscle growth.  To build new muscle our cells must be exposed to higher workloads than they are used to.  If you don’t continuously expose your muscles to some resistance, they will shrink. Muscle is a dynamic tissue that is re-absorbed when not used and rebuilt when its use is required.  This yo-yoing is not a good plan to follow. It is much better to have a good level of everyday conditioning and fitness. It’s like have reserves in the bank if something adverse happens, there are reserves to cover the emergency.  Additionally, it is much easier to maintain good conditioning than it is to build basic conditioning. Building creates soreness, maintaining feels good.

Conventional means of creating high use or greater demand on muscle tissue is to lift heavier weights with shorter rest periods and run harder faster longer. The key is to gradually do more of whatever it is you do. Lifting ten pounds was hard, now it’s easy. Then, increase the weight and repeat. Logical, everyone understands that.

Then there comes a point where the body gets too efficient for that activity to challenge the muscle and progress to get more fit, bigger muscle etc. slows or plateaus. This usually occurs within the first 4 to 8 weeks of increased activity or training. So, the challenge to the muscle tissue must continue to get larger, more varied and more intense.

Eventually there is a point where you cannot lift any more weight, you cannot increase without limit individually. There is an end to human strength potential. Tissue has a failure point. There is a diminishing return on your effort. The whole purpose of increasing weight or running longer or faster was to challenge the body’s limits of recovery, to take the body to the next level. As you increase the activity challenge, there is an increased potential of injury due to the high exertion and the risk of high demand activity.

Remember: Increased demand on muscle, injures muscle and the body responds by building bigger, more fit muscle. Typical ways to increase demand (more weight, harder runs) can also lead to training injuries.

Why WB-EMS is the Best Exercise

Remember: 1/3 of muscle fiber contract at a time.

Remember: muscle fiber has three different speeds of contraction and lengths of fatigue resistance.

Remember: muscle fiber can only contract when and only when a motor nerve sends an electrical command.

Remember: muscle fiber responds to demand of the exertion required and muscle contracts slow twitch to fast twitch in conventional applications. EMS training avoids potential injurious situations and recruits all muscle fibers at once, shortening the time to get a great full workout.

Remember: Increased demand on muscle, injures muscle and the body responds by building bigger, more fit muscle. Typical ways to increase demand (more weight, harder runs) can also lead to training injuries.

Conventional non-EMS systems of exercise training does not and cannot take advantage of the technology designed to maximize muscle response-to-effort with minimal potential injury impact. Plus, conventional training cannot match the short time-in-gym requirement. Every system takes time to train and nothing will shorten the time required for the body to respond to periodic conditioning, however, WB-EMS conditioning requires less time-in-gym due to the rapid way muscle gets to fatigue.

With an WB-EMS suit, the muscle contraction is augmented by the program setting in the system and chosen by the trainer to maximize each training visit. Depending upon the client’s training goals and how they feel on training day, the WB-EMS training is tailored to get muscle to respond to fatigue in 20 minutes. The client receives a deep full exertion to all major muscle groups which cannot be done conventionally in 90-minute sessions.

REMEMBER: Muscle contracts by thirds, always leaving some muscle fiber in reserve?

With WB-EMS training, the electrical signal captures more muscle fiber than any conventional training method. You get more muscle fibers trained in shorter training sessions.

REMEMBER: Muscle has three contraction speeds and levels of fatigue?

With WB-EMS training you can train endurance muscle (slow twitch) and strength muscle (fast twitch) at the same time. The EMS signal will stimulate all muscle fibers concurrently, so your endurance and strength are affected simultaneously. Further, the software programs are so sophisticated that the workout can be shifted to emphasize either endurance or strength and can be changed or modified instantly.

REMEMBER: muscle fiber can only contract when and only when a motor nerve sends an electrical command?

This is a physiological constant. Only neurologically injured persons or certain disease conditions affecting the nervous system can change this fact. Unfortunately, those persons would not be candidates for WB-EMS training. There are other types of electric stimulation that may help them called FES (Functional Electrical Stimulation) but WB-EMS machines are only designed for healthy intact neuromotor junctions. Therefore, WB-EMS is available for everyone and anyone with a healthy nervous system. Any healthy person of any age will receive benefit from WB-EMS.

REMEMBER: muscle fiber responds to demand of the exertion required and muscle contracts slow twitch to fast twitch in conventional applications?

Muscle contraction is constrained by the size of the nerve supplying the muscle and muscle is constrained by its fiber make up, slow or fast fiber concentrations. To recruit more muscle fibers, the exertion must increase. Judging where the risk/benefit ratio goes from benefit to injury can be a moving target not easily judged. When doing lower weight and higher reps you’re challenging the slow twitch fibers more and you get an endurance response. Lifting heavier weight helps to activate more motor units.  A higher percentage of muscle fiber is then fired which stimulates the latent fast twitch fibers. It is no secret that heavier weight puts more stress on the tissue of the muscle as well as tissue of the joints.

EMS training avoids potential injurious situations and recruits all muscle fibers at once, shortening the time to get a great full workout. By increasing the stimulation through the WB-EMS suit, more muscle is stimulated to contract, more fiber of all types contracts without having to lift heavier and heavier weight. You get the benefits of maximal contraction without the risk of potential injury from heavy lifting. It just “feels” heavy! Your joints are saved!

REMEMBER: Increased demand on muscle, injures muscle and the body responds by building bigger, more fit muscle?

Every time you train, you are tearing muscle fibers. All workouts are a teardown. What makes you stronger is the rest periods between workouts where the body responds by building up and repairing tissue damage. The most effective, efficient workouts are the ones that teardown just enough for the body to repair quickly and easily. Working out so hard that you can’t get out of bed for a week makes you sick not fit. Conversely, working out where you can’t feel any exertion doesn’t challenge the body to grow stronger.

Thus, increased strength and stamina from exercise occurs when resting, NOT when you are exercising, so rest periods are crucial for building muscle. Even though it feels good to work the muscle, the magic happens when you are resting between muscle fatigue sessions called workouts.

Muscle fatigue is how muscle responds to activity to get bigger and/or stronger. Muscle recovery is how muscle responds to the tearing down of the training program by repairing tissue to handle the increased demands brought on by training. Fatigue is not just how you feel but how hard the muscle worked in a healthy way. Fatigue is used to describe a condition in which the muscle is no longer able to contract optimally.

Overcoming psychological fatigue is important. At FITtec® we are very aware that fatigue is part of the conditioning process. As clients train, they learn that those feelings are not to be feared but signs of effective workouts. They learn that they can continue to perform even when it feels uncomfortable. This is the reason that elite athletes and motivated people hire trainers that push them and force them to move past the psychological fatigue. The FITtec® trainers are well versed in how to keep our clients motivated and engaged through psychological fatigue.

With WB-EMS, it is not enough to know how to train conventionally. Trainers must also know how the WB-EMS signal supports and augments muscular effort in early stage training and advanced training of elite conditioned athletes as well as the typical client who wants results but is not a competitive athlete.

WB-EMS is not a fad nor a trend but a new, original, here-to-stay way to train and condition people for next level fitness.

Recall that muscles twitch due to a neurologic signal, which is an electric wave that travels in motor nerves at 120m/sec which is almost 270 mph. Electricity from your body is generated by ions such as calcium, sodium, etc. Electricity from a WB-EMS system is electrons that travel at the speed of light. They must move past the resistance of the skin, then move easier in the moist substrate of the body. They don’t interfere with any other functions in the body; they just act as signals to tell muscle to contract. They are travelling at the exact frequency required to stimulate a muscle response as they move from one EMS pad to its partner.  As the workout session progresses, the client voluntarily commands his/her muscles to work and the EMS signal is just the added boost to get the muscle to contract more completely than the muscle could do on it own.

Lifting heavier weight is just another ‘hack’ to get muscle to contract harder; so is running faster or longer. They are also electric demands signaled to muscle to contract. WB-EMS helps the client contract more muscle fiber more completely with less effect on joints. Clients still workout with muscular movements but the added impetus to muscle is electrical, not pounds or pounding effort.

Maximal force, then, is generated with maximum recruitment of muscle fibers and a muscular contraction frequency that completely works the muscle. The muscle stays contracted for 4 to 6 seconds, then rests for an equal or longer time period. (It is called a duty cycle which is a time on, time off cycle). Conventional training systems cannot generate that amount of muscular effort.

That is why a WB-EMS session only lasts 20 minutes. If the on/off cycle is equal, then the muscular body has been maximally contracting for 10 minutes, which is the epitome of HIT. And more than sufficient to reach the muscular fatigue levels necessary for the optimum conditioning goals of the client. Muscle magic by technological collaboration!

Further, one of the best methods to increasing muscle strength is performing eccentric contractions. An eccentric contraction is contracting a tensed muscle at the same time the muscle is lengthening.  An eccentric contraction generates optimum conditions for new growth.  A WB-EMS session continually challenges the muscular body with eccentric contractions. Paired antagonistic muscles are being electrically stimulated to constantly oppose to each other, again maximizing your workout and your training results. 


I hope you enjoyed this deep dive into how muscles, nerves and training works. It is a fascinating look into how the body operates, how we can make it work to our advantage, how we can train like super-star athletes and be safe in the gym. It is with muscles as it is with life: meaningful growth requires challenge and stress, followed by rest and repair. Lather, rinse, repeat.

I hope you can see the electrical nature of muscle activity and how WB-EMS is a natural phenomenon that we build into a more efficient way to train and condition. It should be clear that the electric signal from EMS training does not Shanghai the muscle into zombiesque mindless spasms or replace the voluntary muscle contraction in any way. It supports and augments the amplitude of muscular contraction during a workout. More muscle is firing with less effort, so joints are not in jeopardy from the heavy weight loads needed to recruit higher levels of muscle involvement taking less time to reach fatigue.

I hope you are as excited as we are that WB-EMS is wave of future. Whole Body Electrical Muscle Stimulation Technology is here, and it is here to stay. Fitness and technology are an important combination going into the future. WB-EMS training is beginning to be a big part of fitness now and will only expand as more and more people see how fit they can get the muscular intensity they need for optimum results compacted into shorter time training windows.

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