We have received feedback from current and prospective ARX users that current available sources detailing the supportive science for using ARX is difficult to understand. Below you will find some frequently asked questions and we will touch on specific topics and concepts surrounding the ARX training methodology. It is our attempt to water down the science a bit, while retaining the essence of the conclusions, in order to make an ARX based workout available to as many health seekers as possible.


Part of this difficulty is in part due to the fact that many of the concepts and underlying principles associated with ARX technology run counter to the long standing mainstream exercise model. So much so, that most people do not believe the claims made by an ARX enthusiast. Many will need to suspend that initial disbelief and dig into the research in order for their skeptical mind to accept this new paradigm.


In order to help with this process, I have assembled data taken primarily from the research and conclusions made by Dr. Doug McGuff, M.D. to explain his exercise principles. ARX is not affiliated with Dr. McGuff other than using his research as a platform to structure the ARX workout model.


Additionally, you will find information on how an ARX exercise machine utilizes technology to capture and enhance this new paradigm, and ultimately deliver what I believe is a safer, more effective exercise program.

What are the basics of ARX, adaptive resistance, and how does the machine actually work?


In a nutshell, the ARX is about body development and strength training, but not in the traditional way of using weights. The ARX uses finely tuned motors to provide resistance, that stimulates your body to produce the adaptive response you desire. ARX strength training is done in an environment that is safe and controlled, with the type of quantifiable resistance that is of a quality that cannot be found in the gravity-based technology that is found in gyms all over the world.

How does the ARX measure my progress and resistance?


The ARX machine is equipped with a Bluetooth signal that communicates the data from your session to software , that then stores it,  and is reflected back to you in easily understood charts, graphs, and percentages. You can go back and see your progress over time, the weeks that inroads were charted and in what areas you improved. It is the most consistent and complete feedback of your strength training on any machine to date!

What can I do to maximize my workouts?


It’s important to understand why you are doing what you’re doing. Be ready to work hard. (For just a few minutes a week!) Our bodies instinctively dislike the “inroading” process of building muscle. Many people misinterpret the sensation of discomfort due to the release of lactic acid as a sign of weakness or failure. As a result, many people simply stop at this point. On the ARX, one should try to “live” in this zone briefly; in other words, really dive in deep, and reap the benefits of this natural process of muscle fatigue. Keeping your objective in mind and knowing that your purpose in every ARX session is to weaken the muscles to the point
where you are producing the maximum inroad.

Is it possible to regain strength after a long period of inactivity?


No doubt about it! In just a few weeks, your previous strength levels will begin to return, and the data stored in the ARX software will continue to increase the resistance so that you will experience new levels of health, strength, and fitness.

Why do I need a trainer on the ARX? Why can’t I just do it myself?


At this time, all ARX machines are operated with a remote that must be controlled by your personal trainer. They will check your posture, breathing, and body position for maximized resistance, as well as encourage your progress throughout each progressive set.

What other exercise do I need to do in addition to my weekly sessions on the ARX?


With regular weekly sessions on the ARX machine, it isn’t necessary to have a regimented daily exercise program in place. The only requirement is to remain normally active. For many individuals, constant daily exercise is too much exercise and can send the message to the brain of the “hunter and gatherer” effect. This causes the body to react in a starvation mode which is a command to store more energy, more fat, and to downsize lean muscle. Research has shown that subjects working out on the ARX, who then quit in favor of more traditional, forms of daily cardio exercise, consistently gained body fat and lost lean muscle in just two


I am a believer in regular exercise, but as I’ve gotten older, I suffer from chronic lower back pain. Can working out on the ARX help with this problem?

There can be a number of causes of lower back pain. The smaller and deeper multifidus muscles of the back become relatively weaker over time from our daily periods of standing, or longer periods of sitting hunched over our computers or work stations. The ability to isolate and strengthen the multifidus muscles is one of the great benefits of working out on the ARX. The load on the ARX is shifted away from the larger spinal erector muscles and directly onto the multifidus muscles. Strengthening of the multifidus muscles support rotational forces of the hip joints, spine, and larger musculature. So, the short answer to that question is a big “yes!” ARX helps to relieve lower back pain by isolating and strengthening the muscles that will actually support a healthy
spine as well as body mobility and rotation.

What other health benefits are associated with working out on the ARX?


The ARX technology will address all systems of the body. Some known benefits have been lowering of cholesterol and A1C levels (associated with diabetes), reduce body fat, increase bone density and muscle mass, improve blood pressure, mental clarity, and mobility, to just name a few. Discuss your personal health concerns with Dr. Brittain to fully understand how working out on the ARX will bring relief to your individual medical conditions.


It is common to see an individual stretch prior to beginning their workout. Their goal is to increase flexibility but ironically, most musculoskeletal issues are due to excessive flexibility. Stretching a relaxed muscle pulls apart the joint and it’s connective tissues. This can leave the joint vunerable and unprotected. Joint protection is better accomplished with good muscle tone and strength. Therefore you will not stretch prior to an ARX session.

Warming Up

Sporting activities with high impact forces, need to include some type of stretching protocol. An ARX session does not have impact forces, making it ideal for all ages. The design of the workout automatically accomplishes the warm up phase. Sequentially increasing levels of intensity sufficiently warms up the motor units, beginning with the first rep.


We have noticed that soreness after an ARX session is not a predictable occurrence. It may happen sometimes, but not near as often as you might expect, considering the amount of intensity you exert during a session. Dr. McGuff says that soreness does not have any correlation to muscle growth stimulation. Soreness should not be used as a sign that you received a good workout. Also, as soreness goes away, do not interpret that to mean
you have recovered from your workout. Most often, soreness occurs due to movements that cause muscles to contract over, or around, a bony prominence. Barbell lunges is a good example, as this exercise jams the ischium bone into the gluteus muscle, causing mechanical damage and subsequent soreness. Use of the ARX machine, coupled with safe, controlled isolated movements, mitigates the damage. So within the ARX paradigm, we do not use muscle soreness as an indicator of progress. ARX software monitors your workout and
tracks your progressive strength over time with charts and graphs.


As with soreness, you may notice not sweating during an ARX session, and think to yourself that your workout was not productive. Another exercise myth busted: The truth is there is really no benefit from sweating. We do not sweat off fat. Ironically, excess water loss will hinder fat burning. A dehydrated muscle loses much of it’s ability to perform. Additionally, it takes lots of energy using adrenaline to divert blood flow to the skin, and
activate sweat glands to “break a sweat”. We would rather you use that energy producing more intensity in your workout.


We want you to produce your highest level of effort and deepest level of fatigue to a targeted group of muscles. This requires mental focus to stay with the process of continual intensity to the point of fatigue, even if it is only 90 seconds! Eliminating distractions helps you stay in the moment and work through that desire to quit. With regular weight training, this level of intensity would require a spotter. Fortunately by design, the ARX machine reduces much of those physical safety concerns. Some people like to place their attention outside their body. For those individuals, our ARX machine has a computer monitor, showing you in real time, a graphic display of how you are doing. Others prefer to go within and focus. To facilitate this process, your ARX session will be in a private room with a trainer that knows the importance of form and where you place your attention. You could say an ARX session is as much a mental workout, as a physical workout.


This is a term to represent the extent to which the muscle fibers are being recruited, and going into fatigue, in a sequential pattern. This is important because the potency, or rather the intensity of your exercise stimulus, is equal to how many muscle fibers get recruited during your exercise. The sequence and timing of their recruitment → fatigue interval should be within a specific time frame for maximum benefit. The characteristics of these fibers need further explanation to appreciate this orderly recruitment process.

For sake of simplicity, there are three classifications of muscle fibers:


  1. Slow twitch fibers are slow to fatigue and have good endurance properties. These fibers are easiest for the body to engage, with lots of aerobic capacity and blood supply. These are the attributes that give them good endurance properties. But the slow fibers do not produce much power.

  2. Fast twitch fibers have much more power generating capacity, but fatigue quickly and therefore have low endurance qualities.

  3. Intermediate twitch fibers are somewhere in the middle. (I told you this was watered down)

The slow twitch fibers are the smallest, and the first motor units to be recruited by the brain to move a weight. As these fatigue, they drop out and the slightly larger intermediate twitch fibers get recruited until they fatigue. After the slow and intermittent fibers are fatigued and out of commission, the largest and fastest twitch fibers come into action until they also fatigue. As this is happening, you are becoming progressively weaker.


The fast twitch fibers require the highest energy to engage, so the brain preserves energy, by inroading these different type fibers in the most efficient way.


The following is an excerpt directly out of Dr. McGuff’s book, Body By Science. “If you are able to recruit, fatigue, and weaken muscle fibers within a defined time frame, then you are going to recruit all of the different muscle fibers types aggressively and therefore get the most mechanical and metabolic effect for producing an adaptation. If the exercises are performed properly – that is, in accord with muscle and joint function – you can do so in a way that eliminates all of the other extraneous components, such as excessive force and excessive wear and tear on the joints, which are completely unnecessary for the delivery of the stimulus.”

I suggest you reread the above excerpt. It captures the intent and purpose for following his protocols. And to my knowledge, the ARX machine best facilitates this process. The computer software controls a motorized resistance to facilitate proper recruitment, in a defined time frame. Also, the ARX mechanical design eliminates extraneous components to streamline the delivery of the stimulus. This gives us a vehicle to deliver safe, efficient, and effective exercise, while mitigating much of the excessive force, and wear and tear.

Global Metabolic Conditioning

If you are reading this far into our website, I hope you have noticed that optimizing an individual’s metabolism is a primary service we offer...because there is no patient whose health problem does not have a nutritional component. But many individuals with insulin resistance or diabetes, hormonal imbalance, cardio respiratory issues, etc….will need additional support beyond precise nutrition and optimal diet.
Proper exercise is an obvious health building strategy and dispensing the advantages and protocols of highintensity interval training (HIIT) is a common practice in our office. But we needed more.

Chapter 2 of Dr. McGuff’s book, Body By Science is titled Global Metabolic Conditioning, and details the metabolic shifts linked to his exercise model. By the time I finished that chapter, I was enthusiastic to regularly share his innovations. The metabolic shifts linked to his exercise model was something I was looking for. Dr. McGuff had presented research and an exercise method that was more convincing than ever to adopt.


A safer, more effective, and less time consuming exercise protocol, with real scientific backing.

As any health care practitioner will attest, you can only provide guidance to your patients, and hope they follow through with your recommendations. You can lead a horse to water but you can’t make them drink. We still had too many patients not include proper exercise as a health building strategy. Exercise science needed to innovate again. Fortunately, now we have the ARX technology!