Foundations of Reebok Reactive Neuromuscular Training
By Robert Esquerre
Date Released : 01 Sep 1999


In the never-ending world of entrepreneurial competition, the consumer is constantly faced with choices. Why should I join club A and not club B or C? Or why should I join Club A and not club B or C? The answer to this question deals with the concept of the health club survival code. What makes clubs A, B, and C any better than clubs D,E, or F? Why should a non-member become your club member? Why should a member pay for services for a fee, for example, personal training, in addition to club membership fees? Why should a personal training client pay a club between $1,500 and $5,500+ per year for a personal training program? Why should a club member stay with that personal trainer, and just as important, why should that member renew their club membership? The answer to these questions is multi-dimensional programming.

The normal design assumption for strength training equipment is that it should fit the greatest number of body types possible without becoming complicated or intimidating to operate! However, the design and function of the equipment does not take into account the musculoskeletal functional profile of the individual club member who is to use it. In other words, without knowing the specific structural integrity issues of a club member, a personal trainer would be potentially negligent to put that club member's body under any type of axial load.

The challenge that both club owners and fitness professionals face is twofold: (1) Club owners should purchase equipment that is as biomechanically correct as possible from a design and function standpoint; and (2) personal trainers must make sure that the movement patterns of the individual pieces of equipment are not in conflict with or contraindicated by the musculoskeletal profile of the individuals who are using the equipment. Yes, we are indeed using a well-designed, inanimate piece of strength training equipment; but as fitness professionals, we must have a comprehensive understanding of how to train the most complex machine a personal trainer will ever encounter-the human body- with those inanimate pieces of equipment!

The Scope of Fitness Assessments & Evaluations

From a program design perspective, the fitness professional must determine the musculoskeletal profile of the client before they put load on a human body. For the first time, the only standardized template that exists that will accomplish this objective is Reebok Reactive Neuromuscular Training (RNT). So, the question is: How does Reebok RNT support the concept of multi-dimensional program design?

Before this question is answered, a related concept needs to be woven into this discussion: Can a person be perceivable fit and not be healthy? Based on the reader's current understanding of a "typical" health club member, which picture of GHORT in Figure 1 typifies the member who will potentially use resistance training equipment? In today's health club environment, the traditionally focused, one-dimensional personal trainer will most likely select the figure on the left side. But for those personal trainers who have a broader knowledge base, GHORT on the right side reflects the reality of our members. So if GHORT on the right side is our collective reality, the challenge is how to incorporate this reality check into a member's program.

Figure 1.

If an individualized has a hypomobile shoulder girdle, should they be doing shoulder press work on a selectorized piece of equipment? If an individual has a hypermobile thoracic and lumbar spine, should they be doing squats in a squat rack or Smith machine, or should they be doing a squatting movement on a horizontal leg press machine with appropriate back support? If a person has osteoarthritis in their right patella, should they use a leg extension machine? If a person cannot do abdominal exercises using their own body weight for resistance, should they be using a plate loaded abdominal crunch machine with 110 pounds or resistance? Figures 2 and 3 add a more "human" dimension to the clinical GHORT.

These contraindication-type questions vis-à-vis the client and resistance training equipment means that the club has to develop and/or incorporate into their programming options a new fitness assessment component, one that can optimize the personal trainers' ability to provide the appropriate level of service to their clients. Reebok RNT is an example of this programming option. But before we can further appreciate the programming need of Reebok RNT, we must understand the nature and scope of musculoskeletal imbalances.

Figure 2.

Gait Homonculous Observed Relational
Tabulator (GHORT)
Pelvic tilt short leg syndrome

Figure 3

Effect of different eg lengths and posture. Note presence of scolosis on the side with the "short" limb. (A) Normal (B) Short left femur. (C) Short left tibia (D) Pronation of left foot.

Sources of Musculoskeletal Imbalances

There are four (4) primary causes of musculoskeletal imbalances in the general population: heredity, occupation, recreational and anatomical.

Heredity - The proverbial "You are what your parents gave you" is actually a truism for some musculoskeletal imbalances. For example, leg length deviations are is a potential hereditary issue. The leg length differential adversely impacts the entire human kinetic chain (see Figure 4). Your feet, ankles, knees, pelvis, lumbar and thoracic spine, shoulder girdle and cervical spine are all impacted by this hereditary condition. Yes the potential exists that we, as fitness professionals, can offset and/or correct some of the muscular imbalances we find. However, we are limited in our ability to correct skeletal issues that are associated with these imbalances.

Figure 4

Pelvic Distortion Radiologic measurement of leg length inequality

Females, for example, are predisposed to have a higher incidence of knee dysfunctions that is due to a wide "Q" angle. The greater magnitude of the female "Q" angle [18° for females as opposed to 13° for men]** is associated with a wide female pelvis. Females also have less space in the condylar notch through which the anterior cruciate ligament (ACL) passes. The smaller condylar notch puts excessive pressure/friction on the ACL, which results in premature ACL failure.

Illustration # 1

Illustration #1 depicts Q-angle differences in males and females. Because of the broader pelvis in the female, it is necessary for the femur to come inward at an increased angle to make the distal end of the condyles parallel with the ground. The quadriceps, patella and patellar tendon form an angle centered at the patella. As the quadriceps contracts, the angle tends to straighten, which forces the patella laterally.**

** Magee, D.J., Orthopedic Physical Assessment, 3rd Edition, 1997, pg.507

Occupation - The ergonomic design (or lack thereof) of a member's work environment creates either efficiencies or deficiencies in their functional movement patterns that are specific and unique to their occupation. The location of the desktop computer and the ability to clearly see the computer screen impact the postural integrity of the member's upper quadrant. The additional factor of how far they have to reach for the telephone only increases the nature of the upper quadrant problem. How much time a person sits at their desk in either the correct or incorrect hip flexion position will impact the structural integrity and function of that person's lower back. The high-fashion runway model in the three-inch heels will start to feel discomfort through the entire kinetic chain from the ankle all the way up to the cervical spine.

Recreational/Lifestyle - The proverbial recreational athletes/"weekend warriors" who tend to overexert and/or abuse their bodies while "out with the boys" never seem to fully recover from the impact of their two-hand touch football or paintball war games. Think of the recreational skier who does not adequately prepare himself/herself for the ski season, or the runner who doesn't incorporate cross-training protocols into his/her training regimen. Such behavior continues to create and reinforce musculoskeletal imbalances.


From an anatomical perspective, we have musculoskeletal imbalances or basic imbalances that are caused by how muscles are designed to work. We have two different categories of muscles. Muscles are classified as facilitative, postural muscles or inhibited, dynamic muscles.

The facilitative, postural muscles are basically designed to work to maintain and stabilize posture. These tend to be working all the time and to work overtime they tend to be hypersensitive to hypertrophy. These muscles are, for example in terms of the upper quadrant, levator scapulae, upper trapezius, latissimus dorsi and the pecs. From a lower quadrant perspective, the facilitative postural muscles, again, these are muscles that are actively working to maintain posture: Thoracolumbar spinal erectors; Quadratus Lumborum, Piriformis, Iliopsoas, Rectus Femoris.

Inhibited, dynamic muscles are basically weak by their nature. The only way that they will be strengthened is if we exhert outside load to specifically strengthen these basic muscles. Included in this category from the upper quadrant are the serratus anterior, rhomboids, middle and lower trapezius, upper extremity extensors, i.e., the triceps. From the lower quadrant perspective, we have the Gluteus Maximus, Minimus, Transverse Abdominus, Rectus Abdominus, External and Internal Obliques and Vastus Medialis. These muscles have to be trained and worked in order to maintain strength and balance.

The Concept of Fitness Assessments and Musculoskeletal Analysis

Historically, the role of musculoskeletal analysis went through three distinct implementation phases’ vis-à-vis personal training:

  • Phase 1: No musculoskeletal analyses were performed by personal trainers.
  • Phase 2: More educated personal trainers started to do static musculoskeletal assessments that they had started to learn at various fitness conventions.
  • Phase 3: During the late 1990s, musculoskeletal assessments that were based on functional movement screens started to be incorporated into the personal trainers' scope of practice in different parts of the United States. The Phase 3 effort was finally quantified and formalized by Reebok University in 1997 with the development of Reebok RNT. This assessment tool was directly adapted from one used by our associates in the physical therapy/orthopedic based rehabilitation programs that were used to support collegiate and professional sports programs.

Yes, we agree that we have obtained valuable musculoskeletal assessment information by using the Phase 2-type options. However, once the body is put through normal functional movement patterns, we are able to determine and observe deviations and/or deficiencies that are very specific and unique to the client who is being assessed. These are clearly observations that cannot be quantified in a static screen.

The Concept of RNT: The 21st Century Programming Option

Using Phase 3 as the optimal model, Reebok University has made the programming decision to deal with the human body as a multidimensional kinetic chain that functions in an integrated manner. This means that we, as fitness professionals, have to go below the skin and muscles and start developing programming options that deal with the interrelationship between the nervous system and the muscular system. In fact, we have to start looking at personal training beyond just sets and reps and rather look at it from the hierarchy of the neuromuscular system. This process includes a comprehensive understanding of the following anatomical components of the human body:

  • The central nervous system [Figure 5]
  • The peripheral nervous system
  • Upper & lower extremity nerves [Figures 6 and 7]
  • Motor units & neurons [Figure 8]
  • Neuromuscular junctions [Figure 9]
  • Individual muscle fibers
  • Neurotransmitters (acetylcholine)
  • Muscular contractions


The central nervous system consists of the brain and the spinal cord. The peripheral nervous system consists of all the nerves that lie outside the spinal cord. There are 31 pairs of spinal nerves that exit and enter the spinal cord at the various levels of the vertebrae. Motor information leaves the spinal cord through the ventral root (anterior), and sensory information enter the spinal cord through the dorsal root (posterior) Source: Hamil, J and Knutzen, K.M. Biomechanical Basis or Human Movement, Williams & Wilkins, 1995

Figure 6

Figure 4-2 The upper extremity nerves are shown above. There are nine nerves that innervate the muscles of the upper extremity.

Figure 7

The lower extrimity nerves are shown above. There are 12 nerves that innervate the muscles of the lower extremity


(A) The motor unit consists of a neuron and all of the fibers innervated by that neuron. The motoneurons exit the anterior side of the spinal cord and branch out, teminating on a muscle fiber. (B) Fine motor movements can occur when the motor uunit only services a small number of muscle fibers, such as in the eye. (C) When the motor unit terminates on large numbers of musclw fibers, such as in the gastrocnemius, finer movement capabilities are lost at the gain of more overall muscle activity.

Figure 9

The Neuron and Neuromuscular Junction

The cell body, or (A) soma, of the neuron is located in or just outside of the spinal cord. Travelling from the soma is the (B) axon, which is myelinated by (C) Schwann cells separated by gaps, the (D) nodes of Ranvier. On the ends of each axon, the branches become unmyelinated to form the (E) motor endplates that terminate at the (F) neuromuscular junction on the muscle. Neurons receive information from other neurons through (G) collateral branches

In addition to the above-referenced concept of neurological training, the other major components of RNT include:

1. the concept of joint mobility and joint stability;
2. movement quality versus movement quality; and
3. movement integration versus movement isolation.

As a new analytical tool, RNT provides personal trainers with an expanded base of knowledge that will (1) enable them to identify deficient and ineffective functional movement patterns; and (2) provide them with the technical skills needed to incorporate existing and/or develop additional RNT-based functional movement exercises that can be used to develop corrective and more efficient functional movement patterns for those clients. More important, RNT will facilitate the expansion of the personal trainer's scope of practice.

It is Reebok RNT, as an example of the Phase 3-type protocol that provides fitness professionals with the appropriate data to design multi-dimensional, comprehensive fitness programs for their clients. It is this expanded programming capability that will be a major point of difference between health clubs, regardless of the marketplace.

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