Muscle stimulation for athletes: how it helps achieve better performance

The special advantage of electrical muscle stimulation: escaping natural limits

Perhaps the greatest advantage of muscle stimulation is that it can bypass a fundamental physiological rule of our body that often limits the effectiveness of our traditional workouts. This special capability can revolutionize your training methods.

What is Hennemann's principle and why does it matter to you?

When you move your muscles in the conventional way, your body follows a strict rule known as Hennemann's principle. This means that muscle fibers are always recruited in a specific order: first the small, weak but fatigue-resistant fibers (type I, slow fibers), and then progressively the larger, stronger but faster-fatiguing fibers (type II, fast fibers).

This natural order is usually useful because it ensures economical energy use during everyday movements. However, from an athletic perspective it represents a significant limitation. If, for example, you want to develop your strong, explosive fibers, you must apply a load that causes the type II fibers to "switch on".

How does muscle stimulation break through this limitation?

Electrical impulses — depending on their frequency — can directly stimulate the nerves that control specific muscle fibers. With muscle stimulation you can directly reach and develop, for example, type IIb fibers, which are very difficult and exhausting to activate with conventional training.

It's as if you accessed those muscle fibers that provide the greatest strength and explosiveness through a "back door." This is especially valuable in sports where maximal strength or rapid force production is key to success.

What benefits does this bring in practice?

The first and perhaps most important benefit is time efficiency. While with traditional methods it can take weeks or months to reach certain muscle fibers, electrical stimulation can activate them immediately. This is particularly valuable if you have limited training time.

The second major benefit is selectivity. You can precisely target the fibers you want to develop without overly burdening the others. This allows for very focused improvements, for example increasing the explosiveness of a specific muscle group.

The third significant advantage shows up in recovery. When you directly stimulate the strong fibers and then allow time for regeneration, you may find that they recover more quickly and more fully than after conventional training.

Sport-specific applications

In jumping sports this capability is particularly valuable. Developing fast, explosive fibers can directly improve jump height and take-off speed. For sprinters it means improving start acceleration and maximum speed without excessive fatigue during training.

In strength sports, such as weightlifting or powerlifting, this method allows you to activate the fibers responsible for maximal force production. This is especially useful during periods when you cannot train at full intensity due to recovery from heavy training.

In ball sports, developing the fibers responsible for quick changes of direction and explosive movements can be the difference between good and excellent performance. Muscle stimulation allows you to develop these fibers individually, thus optimizing sport-specific movements.

EMS and Kotz stimulation: which method to choose for maximal results?

If you have read about muscle stimulation, you have probably encountered different terms and methods. The two most important approaches are EMS (or NMES) and Kotz stimulation. Both are effective, but they are optimized for different goals and situations.

What is the difference between EMS and NMES?

In fact EMS (Electric Muscle Stimulation) and NMES (Neuromuscular Electrical Stimulation) practically mean the same thing — electrical muscle stimulation. The term NMES emphasizes that we stimulate not only the muscles but also the nerves that control them, but in practice they refer to the same technology.

Both names denote devices that use low-frequency electrical impulses, generally in the 1–100 Hz range. The effect largely depends on the frequency. For example, it can be used for recovery, strength development, endurance improvement, movement speed increase or pain relief.

What is Kotz stimulation and how is it different?

Kotz stimulation is a specific type of muscle stimulation developed by Russian sports scientist Yakov Kots in the 1970s for training Olympic athletes. This method uses a very specific parameter combination: a base frequency of 2500 Hz modulated with 5–10–30–50–80 or 100 Hz, with alternating work/rest phases.

The specialty of Kotz stimulation is that the high carrier frequency allows the impulses to pass through the skin more easily, penetrating deeper and producing stronger and more comprehensive muscle contractions while causing less discomfort on the skin.

Which is more effective for strength development?

Research shows that both methods can produce significant strength gains, but with small differences. Kotz stimulation typically yields 15–30% strength increases within 4–6 weeks, while conventional EMS can produce 10–25% improvements in the same period.

Kotz's advantage is that it can generate greater muscle force without being excessively painful. This is particularly important if you plan longer treatments or if you find traditional electrical impulses too uncomfortable.

However, effectiveness depends not only on the protocol but also on how consistently you use it. A well-designed EMS program that you follow regularly may be more effective than an occasional Kotz session.

Which method has become more widespread and why?

Worldwide the conventional EMS/NMES approach has become more widespread for several reasons. First, EMS devices are generally more versatile — they can be used not only for strength development but also for recovery, pain relief and rehabilitation.

Another important factor is cost. EMS devices are simpler and cheaper to manufacture, making them accessible to a wider audience. Moreover, most athletes want to use the device for many purposes, not just strength development.

Kotz stimulation has remained more in the realm of specialized, professional applications. Some high-end devices include Kotz programs, but usually as a supplementary feature rather than a main function.

Which should you choose?

If you are just starting with muscle stimulation, a good quality EMS/NMES device is the best choice. These devices include multiple programs, so they can meet a wide range of needs — from recovery to strength development.

Consider Kotz stimulation if you are already experienced with muscle stimulation and want to focus specifically on strength development. Also consider it if you find traditional EMS impulses uncomfortable, since Kotz stimulation usually feels more comfortable.

It is important to note that truly professional electrotherapy devices often provide Kotz-type programs alongside EMS, so you do not have to choose strictly between the two. You can start with basic EMS programs and later experiment with more specialized settings.

Practical tips for choosing

When choosing a device, check what programs it includes. The best devices support both types of stimulation so you can decide which works better for you based on experience.

Always start at lower intensities, regardless of whether you use EMS or Kotz stimulation. Your body will gradually adapt to the electrical impulses and you will be able to tolerate higher intensities over time.

Watch how your body reacts. Some people respond better to one type, others to the other. There is no universal solution — what works for other athletes may not be ideal for you.

What about whole-body stimulation?

The methods discussed so far (EMS, NMES, Kotz) are local applications where electrodes are placed on specific muscle groups and those muscles are targeted. In contrast, there is a completely different approach: whole-body EMS.

In this method you wear a special electrode suit that simultaneously stimulates almost all the major muscle groups (usually at 10–11 points) while you perform conventional exercises.

This technique began in the 1960s in the Soviet space program to prevent astronauts' muscle atrophy. Today it is used in fitness studios and rehabilitation centers and can be particularly effective for people with little time, since a 20-minute session can achieve effects comparable to 2–3 hours of traditional training.

The main difference is that while traditional EMS allows you to develop precisely the muscles you need, whole-body stimulation trains every muscle at once, which is very intense but less specific.

Why might you need muscle stimulation? The most common athlete problems

Time shortage and efficiency issues

If you work or study alongside sport, you know the feeling of wanting to train more but simply not having the time. An average office worker sits 8–10 hours a day, which not only weakens muscles but also degrades movement quality.

Muscle stimulation allows you to "train" your most important muscles even during work hours. A 30-minute stimulation session can have effects equivalent to 1–2 hours of training — of course with the appropriate intensity and protocol.

Asymmetries and lagging muscle groups

Almost every athlete has muscle asymmetries. You may have weaker limbs on the left than the right, or certain muscles may not develop properly after a previous injury. These imbalances not only reduce performance but also increase injury risk.

Traditional training often struggles to correct these asymmetries because the stronger side compensates for the weaker. With muscle stimulation you can specifically target the muscle that needs development, effectively balancing those imbalances.

Slow recovery and overload

If you train regularly, you have likely experienced muscles feeling fatigued for days after loading, sometimes preventing you from following your training plan. This is not only annoying but actually a symptom of a deeper problem. It's important to understand that training doesn't actually make you stronger while you perform it — training's effect is integrated into your body during rest, i.e., recovery.

During training microdamage occurs in muscle fibers, and their healing makes your muscles stronger and bigger. If recovery is slow or incomplete, not only do you fail to improve, but you may gradually weaken. This creates a vicious cycle: slow recovery decreases training quality, which in turn slows progress.

Research shows that applying recovery muscle stimulation within 90 minutes after training can speed up lactate clearance by 25–40% and significantly accelerate microtrauma healing. This means that with faster and more complete recovery you can perform much more intense training without overloading yourself. Practically, this allows you to start each workout fresh and at maximum intensity, yielding faster progress.

This is especially important in sports with multiple daily sessions or weekend competitions. Rapid recovery allows you to start each training or competition fresh and at peak performance — and that can make the difference between good and excellent.

Injuries and forced breaks

Every athlete's nightmare is an injury that sidelines them for weeks or months. A 2–3 week break for knee problems can set back preparation by months, because not only the affected area weakens but other muscle groups lose strength too.

Muscle stimulation enables you to maintain the strength of muscles not affected by the injury. Thus, when you return to full training, you will experience a much smaller setback.

How can medicine and sports science help?

Specialist medical approach

Several medical specialties can help with athletes' performance problems. Sports medicine specialists can assess general physical condition, identify limiting factors and create a personalized development plan.

Physiotherapy is especially useful in treating muscle asymmetries and movement quality issues. Professionals can use specific tests to identify which muscle groups are not functioning optimally and recommend targeted exercises.

Modern sports science approaches

Today's sports science places increasing emphasis on recovery methods. In addition to traditional active and passive recovery, techniques such as cold therapy, compression therapy, and of course electrical muscle stimulation have become widespread.

Research indicates that electrical muscle stimulation outperforms traditional methods in certain areas. It shows outstanding results particularly in neural adaptation of muscles, i.e., improving the brain–muscle connection.

Home muscle stimulation: a new dimension of performance enhancement

Why is home use the future?

The biggest advantage of home muscle stimulation is flexibility. You don't need to schedule appointments or travel to a clinic, and you can apply it at your own pace. It's also much more cost-effective than regular institutional treatments.

Modern EMS devices are advanced enough to be used safely at home. Built-in programs and safety features ensure your muscles receive stimulation at the proper intensity and duration.

When and how to use muscle stimulation?

Timing is crucial for effectiveness. Applied before training it serves as a warm-up and activation tool, while after training it accelerates recovery. The latter is particularly important because removing microtrauma and metabolic byproducts generated during exercise determines how soon you can train again at full intensity.

Recovery muscle stimulation aims to accelerate the natural processes responsible for your body's restoration. Muscle contractions and relaxations create a pump-like effect that improves blood and lymph circulation. This not only speeds the removal of waste products but also enhances the inflow of nutrients and oxygen needed for healing.

On rest days you can perform maintenance or development sessions. It's important to understand that recovery is not passive waiting — it is an active process during which your body becomes stronger and more resilient. The more effective this process is, the more intense training you can do, which exponentially increases the rate of improvement.

Because muscle stimulation triggers the same metabolic processes in muscle fibers and causes the same fatigue as conventional movement, you must plan stimulation into your training schedule.

An average session lasts 20–45 minutes depending on the goal. For recovery, longer 30–45 minute sessions are generally recommended, while for activation shorter 15–20 minute stimulations may suffice. The key is consistent application — recovery efficiency increases when you regularly support these processes.

Which muscles should you stimulate?

The muscles to stimulate depend on your sport and individual needs. Runners should prioritize leg and hip muscles, swimmers the shoulder girdle and trunk, while ball-sport players should focus on muscles that provide explosive power.

In general, you should primarily stimulate the muscles that play a key role in your sport or in which you notice asymmetry or weakness.

Practical protocols for different goals

Strength development protocol

If increasing muscle strength is your goal, use high-frequency (50–100 Hz), short pulse-duration stimulation. This type of treatment produces intense muscle contractions similar to heavy weight training.

Strength treatment sessions typically last 20–30 minutes, 3–4 times per week. It is important to gradually increase intensity and always listen to your body's signals.

Recovery protocol

Recovery treatments aim to improve blood circulation and accelerate the removal of metabolic waste. Remember that training is essentially a "destructive" process — microdamage occurs in muscle fibers and their healing (supercompensation) during rest makes your muscles stronger.

Muscle stimulation is so effective in recovery because it can significantly accelerate the restorative processes. Low-frequency (1–10 Hz), long pulse-duration stimulation creates a pleasant, massage-like sensation while stimulating blood and lymph flow. This accelerates the removal of harmful metabolites and increases nutrient delivery to muscles.

In practice this means that while an intense workout might normally require 24–36 hours for full recovery, effective recovery stimulation can shorten this to 8–12 hours. This allows you to train more frequently at high intensity, which ultimately leads to much faster progress. Consider: if you can do 5 intense sessions instead of 3 per week, that's more than a 50% increase in training load!

Start recovery treatments as soon as possible after training, ideally within 90 minutes. Session duration can be 30–45 minutes and you can apply them multiple times per day if necessary, especially during competition periods or intense training camps.

Endurance development protocol

For endurance improvement use medium-frequency (20–35 Hz) stimulation targeting aerobic muscle fibers. This protocol is especially useful in endurance sports.

Endurance sessions typically last 30–45 minutes and can be performed 4–5 times per week. You can even use this type of stimulation during exercise, for example when using an ergometer.

Recommended EMS devices for athletes

How to recognize a quality device?

A good EMS device offers a variety of programs serving different goals. It is important to have recovery, strength-development and endurance programs. Modern devices may contain hundreds of pre-programmed treatment options.

The display should be easy to read and the operation simple. Many devices today come with a display and intuitive menus that make use easier. Safety features such as automatic intensity limiting and gradual ramp-up are also important.

One of the most important quality indicators is whether the device allows muscle-group selection for certain programs — for example endurance, strength, warm-up or recovery. This is crucial because optimal pulse duration depends on muscle size: an impulse that effectively contracts forearm muscles is not suitable for quality stimulation of a large thigh muscle (quadriceps).

Pulse duration is closely linked to muscle fiber recruitment. Each muscle group has its own optimal pulse duration: smaller muscles are activated efficiently with shorter pulses, while larger muscle masses require longer pulses to recruit deeper fibers. Truly quality devices take this into account and automatically set appropriate parameters based on the muscle group you select. This ensures maximal effectiveness with every treatment, whether you stimulate your calves or your quadriceps.

Entry-level devices

These devices are recommended for those who want to experience the effects of EMS/NMES. A great option is the Globus Elite SII TENS-EMS device, which includes 100 different programs with 2 channels. This variety allows you to find the right treatment for every situation and use settings optimized for different muscle groups.

If you need to treat multiple muscle groups simultaneously, the Elite 150 TENS-EMS device with 4 channels may be appropriate. The 4-channel design allows you to treat up to four different muscle groups at the same time or cover larger muscle areas more effectively. This is particularly useful for recovery or for simultaneously developing symmetric muscle pairs (e.g. both legs).

I am convinced that for anyone training three or more times a week, a stimulator designed for athletes should be considered an essential part of their basic equipment. Alongside intense training, muscle stimulation is not a luxury but a necessity to ensure effective recovery and continuous progress.

Designed for athletes

Sports-specific devices form a special category tailored with program packages specific to particular sports. These devices are not universal solutions but include protocols optimized for the movement quality, muscle use and special needs of a given sport.

The Runner Pro contains programs specifically developed for runners, focusing on leg and hip muscle development and prevention of running-specific injuries. Cycling Pro serves cyclists, emphasizing quadriceps strength and long-term endurance support.

Triathlon Pro is tailored to the combined needs of swimming, cycling and running, with special attention to rapid recovery and muscle activation during transitions. Soccer Pro offers optimized solutions for football players, focusing on explosive strength, quick direction changes and lower-limb injury prevention.

The Champion is the most versatile sports-specific device able to serve several sports and is particularly suitable for athletes who do multiple sports or use cross-training methods.

Professional-level solutions

Among the highest-level devices are the Genesy 1500 and Genesy 3000 electrotherapy devices. These powerful tools not only include traditional EMS/NMES protocols but also offer the aforementioned Kotz stimulation, providing a wide spectrum of the most advanced muscle stimulation technologies.

The Genesy series' uniqueness is that it unites the full spectrum of athletic applications: from basic recovery and strength programs to specialized Kotz protocols and state-of-the-art electrotherapy procedures. This means with one device you can access both widely used EMS methods and higher-intensity, deeper-effect Kotz stimulation.

These devices are especially suitable for serious athletes seeking maximum flexibility and effectiveness. Multi-channel design enables complex treatment protocols, while advanced software supports creating personalized programs. If you want the best technology and do not wish to compromise on functionality, these devices represent the top tier.

Electrodes and accessories

Many accessories are available for the devices to simplify certain treatments. These include special belts, larger surface electrodes and other practical solutions that make application more comfortable and effective.

The most effective stimulation is provided by TENS electrodes. These electrodes are indispensable for home electrotherapy treatments — without them there is no treatment and no effect. The impulse travels from the device to your body through the self-adhesive "pad" attached to the skin.

TENS electrodes are consumables that wear out after some (about 15–20) treatments and need replacement, similar to gasoline in a car. Not all electrodes are equal: quality electrodes have dual gel layers and conductive fibers that ensure more even current distribution and reduce unpleasant prickling. Low-quality electrodes have poor conductivity, requiring higher current to achieve effect, which results in less comfortable treatments.

When using self-adhesive TENS electrodes there is no need for contact gel because the built-in gel layer ensures proper conductivity. However, for durable carbon-silicone electrodes, the use of contact gel is important because these electrodes do not have a gel surface. It is especially important to place electrodes on clean, dry skin for proper effect, and after treatment store them carefully on the supplied plastic sheet in the refrigerator to extend their usable life.

Summary: What to expect and how to get started?

What to expect from a doctor or therapist?

If you decide to seek professional help, you can expect a detailed assessment. This includes examining muscle balance, evaluating movement quality and assessing sport-specific needs.

The specialist will prepare a personalized protocol for you that takes into account your goals, current fitness level and any limitations. You will also receive advice on selecting the right device and using it safely.

Your personal development plan

Introduce muscle stimulation gradually. Work at lower intensity for the first two weeks to allow your body to adapt to the new stimulus. Three to four sessions per week are sufficient to start, and you can increase frequency later as needed.

Keep track of results. Keep a training log that records stimulation sessions as well. Observe how your recovery, muscle strength and general well-being change. Most athletes notice measurable improvement after 2–3 weeks.

Combine stimulation with traditional training. Muscle stimulation does not replace sport-specific training but complements it. You will achieve the best results by using both with appropriate timing and intensity.

When to avoid muscle stimulation?

In certain cases muscle stimulation is not recommended or can even be dangerous. If you have a pacemaker or another implanted electrical device, do not use EMS without medical consultation.

Avoid use during pregnancy, epilepsy, acute inflammation, fever or infection. If you have any skin problems where electrodes would be placed, wait until they heal.

Also be cautious with fresh injuries. Do not apply stimulation near acute pain, swelling or open wounds. In such cases a medical examination is necessary first.

Possible side effects and their management

The most common side effect is skin irritation at the electrode sites. This usually results from incorrect electrode placement or too high intensity. If you experience redness or itching, reduce intensity or reposition the electrodes.

Sometimes muscle soreness may occur after treatment, especially in the first weeks. This is a normal reaction similar to training-induced soreness. Recovery programs and proper hydration can help alleviate this feeling.

Rarely, headaches or dizziness can occur, particularly if you start at too high an intensity. Always increase intensity gradually and stop the session immediately if you feel discomfort.