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9 Articles in Volume 8, Issue #9
Fibromyalgia: Fibromyalgia Medical Education
IV Ketamine Effect on Post-Concussional Migraine
Management of Chronic Headache
Multidisciplinary Pain Clinics vs Opioid Treatment for Chronic Pain
Neurodevelopmental Basis for Chronic Regional Pain Syndrome
Neuromuscular Training in Pain Management
Opioid-induced Sexual Dysfunction
Sphenomandibularis Muscle and Retro-Orbital Headache
Therapeutic Laser Evolution—Part 2

Neuromuscular Training in Pain Management

Re-activation of the deep local stabilizing muscles of the spine has been demonstrated to be an essential part of rehabilitation for the musculoskeletal system and, in particular, mechanical spine pain.

How many people would think of using some form of exercise as primary pain management? If you’re the typical practitioner who perhaps doesn’t get the opportunity to read the latest research in the sport sciences, you might answer, “Not many.” In this clinical report, I would like to draw attention to the increasing body of research appearing in both the strength/conditioning and pain therapy realms that is providing evidence for lumbo-pelvic core stabilization training as a method to restore normal function while, at the same time, reducing spinal pain. There is still continuing debate as to which specific methods are the best, but a general consensus is forming regarding the presence of a muscle impairment component to many of the mechanical/ idiopathic low back pain syndromes being seen by practitioners today.1 The phrase ‘core stabilization training’ has become popular and somewhat in vogue with trainers and therapists alike. Stabilization is not the same as strengthening yet many practitioners continue to use the terms synonymously. The Redcord method of core stabilization was developed in Norway in the 1990s and represents one of the most popular techniques for specific core stabilization treatment through neuromuscular re-activation (neurac). We will begin our discussion with semantic clarifications while examining the main premise behind Redcord therapy.

Strength vs Stabilization

There have been many methods or systems of strength training that have evolved over the years. It is thought that most of these methods have contributed substantially to strength training and functional restoration. The most common training techniques, in the order that they became popular, have generally been categorized under the contraction type and/or load imposed on the muscle:

  • isometeric – resistance against immovable force
  • isotonic – resistance provided by a weight/plate
  • isokinetic – for every 1 unit of force there is 1 unit of resistance; water therapy and elastic bands are considered crude forms of isokinetic resistance
  • isoinertial – systems controlling acceleration/deceleration
  • isodynamic – systems controlling motion

More recently we have seen the advent of functional and hybrid training methods which re-focuses the goal on grooving movement patterns as opposed to isolating a particular muscle group. Rehabilitation specialists take more care these days in training coordinated, balanced and integrated movements, as opposed to simply improving strength/muscle endurance of an injured muscle/joint

There are three types of contractions or actions that occur in muscle: concentric, eccentric (both dynamic), and isometric (static) contractions. In concentric muscle actions, the muscle contractile units shorten and is also known as a positive contraction. In eccentric actions, the muscle contractile units develop tension while simultaneously lengthening and is also known as a negative contraction. When a muscle develops tension but does not shorten or lengthen, this is referred to as an isometric action. Human function consists of all three types of muscle actions, but mostly eccentric. When persons are strength training, they typically are working toward increasing the contractile properties of muscle and will do so in all three mode combinations. Lumbo-pelvic core stabilization is a neuro-muscular event and does not necessarily refer to simply increasing the tensile or contractile properties of muscle—rather, it refers to the ability of a muscle or muscle group to activate in support of a movement not in actual motion itself.

Peripheral Joint Stabilization

Stabilization is a motor control strategy that serves to protect a vulnerable area such as a joint or series of joints as in the spine. As an example, in the periphery, when shoulder elevation occurs in a healthy individual there is a simultaneous contraction or action of the deltoid which acts as the primary mover, and the rotator cuff muscle group which acts as a stabilizer. In this case, the rotator cuff muscles hold the head of the humerus steady as the deltoid acts against this stabilization force to elevate the humeral segment via a concentric contraction. As the arm is released, the rotator cuff group maintains the position of the humeral head in the glenoid fossa as the deltoid produces an eccentric contraction thereby allowing the arm to drop back down in a controlled manner. This is an example of a force-couple situation and is common in peripheral joints. In this example we see the deltoid as the primary mover and the rotator cuff muscles as the stabilizers or secondary muscles acting to support the primary movers (synergists). In a pure shoulder external/internal rotation situation, the roles of the muscles are reversed with rotator cuff muscles acting as the primary movers causing rotation while the deltoid muscle acts to stabilize this motion with a concurrent isometric contraction. What we learn from this simple example is that muscles have various functions including direct generation of motion in a joint as a primary mover or acting as a stabilizer to support other muscles in motion.

Figure 1. Redcord system includes series of elastic bands and cords suspended by a set of trainers attached to a metal framework that is supported by a ceiling truss system Figure 2. Redcord method allows the therapist to create a safe and effective (unstable) exercise environment.

Muscles function in different ways depending on the situation. They can act to generate strength so as to move a bony lever (arm or leg) through a range of motion thus creating joint torque. They can also act to support or stabilize a movement such as that described with the shoulder.

Peripheral joint stabilization in the knee and shoulder, for instance, involves co-contractions whereby the agonist (primary mover) and antagonist muscle groups contract or turn on at the same time, creating stiffness or stability in a joint. In the knee, there is co-contraction during weight acceptance in the gait cycle. Proper functioning of the peripheral joints involves not only co-contraction, but also reciprocal inhibition of antagonists during agonist activity. Using the example of gait: when the knee extensors, or agonists, contract during leg swing, there should be a simultaneous graded reduction (inhibition) in knee flexor activity. Without this reciprocal inhibition, there would be two opposing muscle contractions (co-contraction) leading to joint fixation or rigidity—not conducive to effective locomotion. This coordination involves timing and sequencing of muscle activity and leads to a smooth rhythmic motion. The central nervous system is the mechanism by which the timing and sequencing of muscle dynamics is coordinated and harmonized into a seamless and connected series of movements. It is this fine and precise neuromuscular control mechanism that appears to become disrupted as a result of injury or surgery to the spine.2

Trunk Stabilization

Spinal stability is achieved in a different manner than in peripheral joints and it is more useful to think of spinal stabilization in terms of functional anatomy versus structural anatomy. The lumbo-pelvic core (LPC) is composed of an inner, deep layer of muscles such as transverse abdominis (TA) anteriorly and multifidus posteriorly, also known as local muscles. The more superficial muscles laying over the top of these deep structures in the posterior are the paraspinals (erector spinae and quadratus lumborum) with rectus abdominis and the oblique muscles in the anterior portion of the core. Research is showing that pain in the lower spine will inhibit or deactivate the deep local stabilizing muscles of the spine-almost like flipping off a light switch.3 Unfortunately, the switch doesn’t automatically get turned back on again once the inhibiting pain is gone. If local stabilizing muscles are not active during exertional/postural activities, a person will be at higher risk for injury. There is some evidence suggesting that, in these susceptible individuals, there is an increase in superficial or global muscle activity—as measured by EMG—in an effort to compensate for poor deeper or local muscle activation.4 As in peripheral joints, spinal joint stabilization requires some degree of co-activation with the deep core muscles which probably need to activate first in anticipation of (feed forward activation) or during planned activities and followed by activation of the more global or superficial muscles—both working together synchronously to form one functional system.5

Redcord Method

The Redcord system (see Figure 1) is comprised of a series of elastic bands and cords suspended by a set of Redcord trainers attached to a metal framework that, in turn, is supported by a ceiling truss system. The cords/elastics are attached to the Redcord trainer that controls positioning, rope length, and tension characteristics of the system. The basic premise for Redcord application lies in their proprietary method of evaluating patients using a ‘weak link’ system. Using this weak link system identifies a biomechanical weak point and the most vulnerable muscles/joints or muscle groups are then identified through a series of special tests. Based on this evaluation, a specific stabilization protocol is implemented to try and correct the functional instability. All exercises are performed with the patient in a non-painful position and any exercise is terminated if there is pain. This is important because pain is thought to inhibit muscle activity that, in turn, precludes that muscle from fully activating or developing tension. Some of the distinct and unique features of Redcord system are that the therapist or conditioning professional can control a number of resistance and motion characteristics such as lever length (short versus long), activation patterns (i.e. agonist/antagonist in closed kinetic chain exercise and agonist/synergist in open kinetic chain exercise), total or partial body suspension, and level of perturbation or instability. This last point is important for persons with low back pain but not so much for persons using Redcord for training and conditioning purposes.

This Redcord model of spinal stability has been adapted from the seminal work conducted by Bergmark and modified with more contemporary research findings from other researchers.6 The idea behind many of the exercises performed with Redcord is that the activity is performed with perturbation provided either by cord vibration, body segment suspension, or the use of balance discs that are inherently unstable. Redcord training is performed in an environment of instability that further stimulates the stability muscles to activate. There is evidence to suggest that an unstable environment is not as necessary in activating the stabilization function of the deep core muscles in a healthy population, but instability does appear to be an important, maybe critical, prerequisite in patients suffering from low back pain due to injury or surgery. In the absence of pain during an exercise, the Redcord method allows the therapist to create a safe and effective, unstable exercise environment (see Figure 2). The level of difficulty can easily be adjusted by simply lengthening the primary lever or resistance arm. For example, moving the sling from above the knee to just above the ankle when doing hip extension exercises (see Figures 3a and 3b). Other exercise parameters such as repetition number and isometric hold times can be varied to increase or decrease workout intensity.

Figures 3a and 3b Hip extension exercises with varying position of the sling from above the knee to just above the ankle, respectively.

Another operational advantage of using Redcord is that it has a very small footprint which allows the system to be used effectively in any small office. It is recommended that the Redcord be used in conjunction with a hydraulic table for even more versatility. Redcord centers all across the U.S. are treating a wide array of clients—from wheelchair bound patients to elite athletes. The benefits to patients have been numerous and include an enhanced sensorimotor workout which effectively targets the body in a different manner than most other conventional training systems. The Redcord patient is forced to not only re-activate deep local muscles that have not been used for some time and quite possibly have atrophied as a result of injury, but this exercise format also enhances proprioception/kinesthesia and balance in general.,7 These are all desirable attributes found in the healthy neuromuscular system but lacking in the diseased, deconditioned, or injured individual. As well, research in motor control has found that healthy persons have an intact feed forward mechanism (FFM) which is a CNS-mediated pre-activation of target muscles in anticipation of a load, such as when a person is planning to pick up a gallon of milk. This mechanism prepares (pre-sets) the musculo-skeletal system for a task or activity and, by doing so, avoids potential injury. In the lumbo-pelvic or trunk region, this would take the form of prophylactic “bracing” milliseconds prior to lifting a weight or, perhaps, just before being struck from behind by another car. Studies have shown that there is a deficit or reduction in FFM in those people with cervical or lumbar pain.8 It is thought that neuromuscular training techniques such as Redcord can re-activate this mechanism thereby re-establishing proper neuromuscular control and trunk stability. This can lead to significantly improved pain reduction and overall injury prevention.

Conclusion

There is a growing trend in both rehabilitation and fitness/conditioning that involves the use of neuromuscular training techniques especially for those persons with a history of low back pain. In this population, there is a tendency for the deep local stabilizing muscles to become inactive secondary to pain stimuli. This results in the more superficial global muscles to overwork, which is, in itself, pain-inducing and makes the person more vulnerable to further injury due to the inherent lack of stabilization potential in the core region of the body. Through neuromuscular re-activation exercises, the patient learns to turn on the stabilizers so that the strengthening process can begin. It is the stabilization response that can be strengthened, but only after patients learn to actually initiate stabilization. Redcord neuromuscular re-activation has been demonstrated to be an essential part of rehabilitation for the musculoskeletal system and, in particular, mechanical spine pain. Sonographic research has confirmed the deep stabilizing properties of this form of training and conditioning in those patients afflicted with back and neck pain.9 It is less clear whether or not the magnitude of the response to neuromuscular re-activation training is equal in those populations not afflicted with musculoskeletal pain. It also not known whether neuromuscular re-activation training alone is more efficacious than more traditional training methods or if the addition of this form of training to conventional strength training would yield the most optimal results.

Last updated on: December 13, 2011
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