Manual Resistance Techniques
Craig Liebenson
Curtis Thor Rigney
LEARNING OBJECTIVES
After reading this chapter, you should be able to:
Understand the different methods of muscle relaxation.
Understand the physiology of muscle inhibition.
Understand the key role of identifying the barrier to resistance and achieving a release phenomena.
Understand how to lengthen the most clinically relevant muscles in the body.
“The Artist is one who detects and applies the law from observation of the works of Genius, whether of man or Nature. The Artisan is one who merely applies the rules which others have detected.
–HENRY DAVID THOREAU
Introduction
Manual resistance techniques (MRTs) have their origins from both the proprioceptive neuromuscular facilitation (PNF) philosophy of physical therapy and muscle energy procedures (MEPs) of osteopathy. These techniques involve some form of resistance, usually provided manually, of a patient’s isometric or isotonic muscular effort. A lengthening of a short, tense, or tight muscle usually follows this effort. The primary intent of MRTs is to relax overactive muscles or to stretch shortened muscles and their associated fascia. Many methods have been developed depending on the clinical goal. To achieve these positive clinical effects, MRTs are thought to take advantage of two physiologic phenomena: post-contraction inhibition1 and reciprocal inhibition (RI).2 MRTs are considered to be invaluable workhorses in the rehabilitation of the motor system.
In addition to lengthening muscles, MRTs may also be used to facilitate or train inhibited or weak muscles. Manual resistance allows the doctor or therapist to achieve precise patient positioning and control of movement in a way that is not possible with machines or even free weights. Manual contacts also allow for varying proprioceptive stimulation to facilitate an inhibited muscle during active resistance. The value of clinician control over resisted exercise cannot be underestimated, especially when improved coordination and motor control are goals as important as strengthening. Whether MRTs are used to relax, stretch, or facilitate and train muscles, they fulfill an important role in patient education and activation by enabling the patient to gain guided kinesthetic awareness of how to perform home exercises in a safe and beneficial manner. This chapter will focus on procedures that lengthen muscles.
In the late 1940s, publications about the use of PNF to facilitate neurologically weak muscles appeared.3 Soon other publications followed, reporting that spasticity responded as well.4 This led to the development of various forms of PNF (i.e., hold-relax [HR] and contract-relax [CR]), which could be used for orthopedic as well as neurologic problems. The osteopaths used MEPs primarily to mobilize joints; they also developed a variety of modifications that could be used to stretch shortened muscular and connective tissues as well as to strengthen weak muscles.5
Manual medicine practitioners in Europe were not far behind in incorporating these new methods. Gaymans and Lewit wrote of success using these techniques for joint mobilization using specific eye movements and respiratory synkinesis to enhance the physiologic effectiveness of the procedures.6,7 Later, Lewit6 focused on a gentle muscle relaxation technique he termed post-isometric relaxation (PIR), similar to HR, which was applied to the contractile portion of an overactive muscle.8
Neurophysiology
There are two aspects to consider when using MRTs to lengthen muscles. The first is to consider the relaxation of an overactive muscle (increased neuromuscular tension, “spasm,” or trigger point [TrP]). The second is to increase the extensibility of a shortened muscle and its associated fascia when connective tissue or viscoelastic changes have occurred. When using MRTs, it is recommended to relax the neuromuscular (contractile) component of the muscle before attempting any forceful stretching maneuver. For, even if connective tissue/noncontractile pathophysiologic changes have occurred, it is still valuable to relax the neuromuscular apparatus before stretching. The relaxation technique is thought to inhibit the stretch reflex, allowing for more vigorous stretching to be well tolerated by the patient and helps avoid damage to the muscle sarcomeres that may be associated with stretching of a non-relaxed muscle.
Clinical Pearl
Differentiating Neuromuscular Versus Connective Tissue Involvement in Decreased Muscle Length
Length changes in muscles may be caused by neuromuscular or connective tissue factors.
Often a muscle has a decreased length but only needs to be relaxed rather than stretched to achieve a normal resting length.
The diagnostic test of whether the muscle’s length deficit is caused primarily by neuromuscular factors is if it lengthens spontaneously after relaxation techniques such as PIR without requiring stretching methods.
If the muscle does not lengthen after PIR, then it is likely that the muscle’s reduced length is caused by connective tissue factors and stretching will be required.
Two neurophysiologic principles formed the original hypotheses to explain the basis of these techniques. The first being post-contraction inhibition,1 which states that after a muscle is contracted, it is automatically followed by a state of relaxation or inhibition for a brief, latent period. The second is RI, which states that when one muscle is contracted, its antagonist is automatically inhibited. For instance, if the quadriceps is contracted, this inhibits the hamstrings thus allowing for easier relaxation or stretching of the hamstring. This is based on Sherrington’s law of RI.2 RI’s purpose is to allow an agonist (i.e., biceps) to be able to achieve its action (flexion) unimpeded by its antagonist (i.e., triceps). Various other explanations have been proposed for how the effects of MRTs are achieved. These include autogenic inhibition, Golgi tendon organ stimulation, reciprocal innervation, presynaptic inhibition of Ia afferents, resetting of the gamma system, and postsynaptic inhibition. It has been demonstrated that the receptors responsible for this inhibition are intramuscular and not in the skin or joints.9
These original hypotheses have not been verified by recent studies.10,11,12 It appears that the expected electromyography (EMG) findings of decreased muscle activity did not occur. Instead, an increase in activity had been demonstrated following the prescribed muscle contractions. This has led to another hypothesis. It has been suggested that the positive effect of MRT procedures is due to a modification of the stretch perception or stretch tolerance.13,14,15 This modification allows the patient to tolerate greater muscle lengthening. MRT may have a type of analgesic effect that increases the tolerance.16,17
The Hoffman reflex activity, which represents the excitability of the motoneuron pool, has also been studied in relation to MRT. Early investigations had shown that it is inhibited for up to 25 to 30 seconds after an agonist or antagonist contraction, whereas during static stretching this inhibition only lasts approximately 10 seconds.18 More recently, the resultant inhibition was found to last around 1 second, suggesting that muscle lengthening should be performed quickly to take advantage of the inhibition.19 Regardless of the effect’s duration, it has been found to be neurologically mediated and is not a result of any mechanical effect.11
The viscoelastic properties of tissues have also been investigated. Muscle fibers have certain biomechanical characteristics that affect their stiffness. Skeletal muscle fibers are known to adapt to imposed demands. For instance, during growth, muscle length increases as new sarcomeres are added in series and individual fibers increase their girth.20 Prolonged immobilization of a limb joint in an extended or shortened position results in an increase or decrease in the number of sarcomeres, respectively.21,22 When immobilized in a shortened position, muscle stiffness increases.21 It has been observed that an increase in connective tissue occurs with immobilization in a shortened position.23
Connective tissue proliferation is minimized if the immobilized muscles are placed in a lengthened position or their contractile activity is maintained with electrical stimulation.21,23 Therefore, either passive stretching or maintenance of contractile activity in immobilized muscle can prevent muscle shortening and connective tissue proliferation.
Shortened muscles that have been immobilized require approximately 4 weeks of treatment to return to their pre-immobilization length.21 Muscle stiffness in response to stretch varies on the basis of intrinsic molecular properties of muscle fibers. Muscles that are kept still increase their stiffness 2-fold in just a few minutes.24 Conversely, oscillations and isometric and eccentric muscle contractions all reduce muscle stiffness.24,25
This plasticity of muscle fibers in response to passive or active movement is described as thixotropic behavior. Thixotropy refers to changes in viscosity and resistance to deformation of the intrinsic molecular makeup of muscle fibers that result from shaking or stirring motions. Both intrafusal and extrafusal muscle fibers have thixotropic properties.26
Thixotropic bonds are thought to occur between actin and myosin filaments.26,27 Such bonds or cross-bridges form easily in muscles. According to Hagbarth, “After stretching or passive shortening, it may take 15 minutes or more before muscle fibers spontaneously return to their initial resting length.”26 He also stated, “Strong isometric contractions and muscle stretching maneuvers are likely to dissolve preexisting actomyosin bonds and thereby reduce the inherent stiffness of the extrafusal muscle fibers.”26
Evidence About Stretching
The majority of research on stretching involves the more aggressive versions such as static stretches and the aggressive PNF stretches like CR or HR. There is a paucity of information within the literature regarding Lewit’s gentle muscle lengthening, PIR. This section
will therefore focus on the evidence around the more aggressive stretching procedures. A literature review evaluating stretching identified several key points for clinical application28:
will therefore focus on the evidence around the more aggressive stretching procedures. A literature review evaluating stretching identified several key points for clinical application28:
Whereas use of cryotherapy or heat can increase a stretch’s effectiveness in increasing range of motion (ROM), “only warm-up is likely to prevent injury.”
For healthy individuals, a single 30-second stretch per muscle group will increase ROM; however, clinicians may need to increase the length of stretch or number of repetitions for certain individuals and for certain injuries or muscle groups.
PNF has been identified as the most effective technique to increase ROM, but it is important to note that during PNF techniques, the targeted muscle often undergoes an eccentric contraction during the stretch, which can increase risk of injury to the targeted tissues.
Behm and Chaouachi’s review33 concludes that stretching should not be part of a warm-up routine but recommend that stretching should play a part in overall fitness and wellness because of the functional benefits associated with increased ROM and musculotendinous compliance. There is a fair amount of evidence in the literature that supports the use of MRT for increasing ROM.34,35,36,37,38,39,40,41 It should be noted that others have found that MRT adds no benefit over static stretching for increasing ROM.42,43,44,45
The main concern about using MRT as part of a warm-up is due to its potential effect on muscle performance in relation to the hypothesized neurologically mediated effects. It is believed to inhibit motor function and indeed some studies demonstrate a decrease in muscle performance following MRT.44,46,47 Others who found an increase in motor performance following MRT34,36,48 contradict the previous findings. Yet others have found no change to motor performance resulting from MRT.49,50,51 Some of these inconsistent results may be a reflection of the inconsistencies between the studies. For example, some studies used CR whereas others used HR. The protocols for each of these techniques were inconsistent in themselves. There is no definitive conclusion regarding MRT’s effect on muscle performance. Its use in a warm-up routine is at the practitioner’s discretion.
A second issue to be considered regarding the different studies is the fact that there may be subgroups of patients in whom stretching is effective. A study may mistakenly consider a heterogeneous group to be a single homogenous group and miss the smaller subgroup.52 The literature suggests that such subgroups do exist.53 For instance, Biering-Sorensen found that increased trunk flexion mobility, not hypomobility, predicted future low back pain (LBP) in men.54 It has also been recently reported that patients with spondylolisthesis tended to be hypermobile, whereas those with spinal stenosis, disc prolapse, or degenerative disc disease tended to be hypomobile.55 Thus, if a large number of heterogeneous individuals were clumped together into one single group, the effectiveness of specific interventions for each smaller subgroup would be missed.52
Decreases in hip internal rotation have shown to correlate with LBP.56,57 Tight muscles (iliopsoas and gastroc soleus) are shown to be correlated with increased injury risk, especially of the knee, in male college athletes.58 McGill et al have recently found that decreased hip extension mobility is correlated with disabling LBP.59 Van Dillen et al reported that chronic LBP subjects had less passive hip extension mobility than asymptomatic subjects.60 Studies in adolescents have documented that future episodes of LBP are correlated with decreased hip extension mobility.61 Some controversy exists, however, because Nadler et al reported that hypermobility in the lower extremity was correlated with future LBP in college athletes.62,63
Different Methods for Muscle Lengthening
PNF is the most complex system of MRTs.60 In PNF, neuromuscular reeducation is the goal. Manual contacts, patient pre-positioning, muscle contraction against resistance, irradiation, and verbal commands are all used in concert to begin the process of improving movement. Its most commonly used inhibitory techniques are HR, CR, and rhythmic stabilization. HR involves isometric resistance and is used mostly for pain relief. CR is used for stretching tight muscles and related soft tissues. This method incorporates isotonic resistance and multiplanar, usually diagonal, movement.
When osteopathic physicians use MRTs, they intend to mobilize joints, as well as to strengthen and relax muscles. They called these methods MEPs.5 They refer to a joint or tissue with limited physiologic
motion, determined through manual palpation, as having a “pathologic barrier” (see Chapter 28). The physiologic barrier is assessed at the end of a joint’s or muscle’s passive ROM. The term “pathologic barrier” is assigned if premature or increased resistance is felt during motion assessment. MEPs were developed by the osteopaths as alternatives to thrust manipulation procedures for restricted joint mobility and required the use of gentle forces. They were also used on muscles in a way similar to PNF.
motion, determined through manual palpation, as having a “pathologic barrier” (see Chapter 28). The physiologic barrier is assessed at the end of a joint’s or muscle’s passive ROM. The term “pathologic barrier” is assigned if premature or increased resistance is felt during motion assessment. MEPs were developed by the osteopaths as alternatives to thrust manipulation procedures for restricted joint mobility and required the use of gentle forces. They were also used on muscles in a way similar to PNF.
In Europe, manual medicine physicians soon began experimenting with these methods. Lewit and Gaymans64 wrote of success using these techniques in an extremely gentle fashion. At first, they used the rhythmic stabilization approach borrowed from PNF. Later, Lewit6 focused on the HR approach. He found that an excellent muscle relaxation and improved muscle resting length could be achieved by positioning an overactive muscle at its pathologic barrier, then resisting the patient’s very gentle isometric contraction before lengthening the muscle. Lewit termed this approach PIR. Lewit and Gaymans64 also incorporated specific eye movements, in which the patient is asked to look in the direction of contraction during the isometric phase of the procedure and in the direction of muscle lengthening/relaxation during the inhibitory phase. In addition, breathing in facilitates contraction and exhaling aids in relaxation for most muscles. These enhancements were termed visual and respiratory synkinesis, respectively. Lewit felt that only the gentlest force was required.6
Janda, another European, used HR with significantly greater forces for treating true muscular and connective tissue shortening.65,66 This adaptation, termed post-facilitation stretch (PFS), is used for chronically shortened muscles. The patient performs a maximal contraction with the tight muscle in a midrange position. On relaxation, the doctor quickly stretches the muscle, taking out all the slack. The various MRTs are summarized in Table 29.1.
Table 29.1 Manual Resistance Techniques | ||||||
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Practice-Based Problem
Can Manipulation Be Applied to All Mobile Structures Possessing Movement Restrictions?
The goal of manipulation is to mobilize tissue. Generally, manipulation is considered only for joints with movement restriction. However, can it be applied to skin, soft tissue (fascia), muscle, or joint?
A tissue with a movement restriction has a “pathologic barrier.” In other words, it has a premature loss of mobility and/or its quality of end-feel is abnormal (e.g., poor joint play or resilience). Manipulation is designed to improve mobility (quantitatively or qualitatively). When a “pathologic barrier” is perceived, the goal of manipulation is to achieve a “release phenomenon.” Generally, release is achieved in joints with a thrust that creates cavitation.
Another Clinical Question Arises—Namely, Can a “Release Phenomenon” Be Achieved Without Force?
Naturally, joints can be pulled (traction), rocked, or oscillated. Muscles can be lengthened to their barrier and then after post-isometric relaxation a “release phenomenon” can occur, thus mobilizing the barrier. Scars, fascia, and muscle can be lengthened and held. Merely holding and waiting during a latency can achieve the simplest of all “release phenomena.”
What Effect Can Repeatedly Cavitating a Joint Have on the Normal Protective Barrier? In Other Words, Can You Cavitate a Joint Over and Over Again?
Within a brief time frame such as 15 minutes, you cannot achieve repeated audible releases in a joint capsule. There is a normal, non-pathologic barrier that should be respected in tissues. If tissues are too frequently or too forcefully manipulated, the normal protective barrier can lose its function. Unfortunately, in the pursuit of the goal of improving tissue mobility, instability may be produced!
Classification of Tense and Tight Muscles
According to Janda, certain muscles tend toward hypertonus (including tightness/shortness) and others toward inhibition (and weakness) (see Chapter 11 and Table 11.2). He also has emphasized that it is possible to divide muscle hypertonicity into a variety of different treatment-specific categories.67 Muscle dysfunction is typically caused by either neuromuscular or connective tissue factors. Different types of dysfunction include reflex spasm, interneuron facilitation from joint dysfunction, TrPs, central nervous system influences (i.e., limbic system involvement), and gradual overuse (see Tables 10.2 and 29.2).
Table 29.2 Classification of Tight or Tense Muscles | ||||||||||
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Types of Functional Hypertonus According to Janda67
Limbic system dysfunction—Caused by psychological stress. You will see increased muscle tone diffusely over the shoulder-neck area, low back, and pelvic muscles. The effected muscles will be tender to touch and the whole area will be involved with a sharp line of transition between the dysfunctional area and the normal area. TrPs may tend to develop in these muscles.
Interneuron dysfunction—The interneuron is believed to be the most delicate part of the reflex arc that can become disrupted by aberrant afferent information being sent to it because of spinal or peripheral joint dysfunction. This then causes the muscles in the related segmental area that are prone toward hypertonicity to become hypertonic. These muscles will be predisposed to the development of TrPs and their “antagonists” will become reciprocally inhibited and hypotonic.
Myofascial trigger points—This is an area of local congestion within the muscle that comes about as a result of sustained shortening of a fascicle of muscle fibers. TrPs are common pain generators and should be thought of not as disorders that alter function but as results of dysfunction. A TrP is a hyperirritable spot, usually within a taut band of skeletal muscle or in the muscle’s fascia, which is painful on compression and can give rise to characteristic referred pain, tenderness, and autonomic phenomena.68
Reflex spasm—This is muscle spasm as a response to nociception. It frequently acts as a splinting mechanism, for example, antalgia caused by LBP or abdominal “rigidity” caused by appendicitis. Once the underlying pain process resolves, the muscle hypertonicity often remains and must be treated. This can lead to TrP or faulty movement pattern development.
Muscle tightness—This is a myopathologic and neuropathologic state in which the muscle becomes hyperactive and shortened most commonly because of overuse. Postural habit may also contribute to the development of muscle tightness through consistent periods of prolonged postures where muscles are kept short. Sitting, for example, places the psoas and hamstrings in a short position.
Table 29.3 Specific Treatment for Different Types of Muscle Tension/Tightness | ||||||||||||||
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Making a precise assessment of soft tissue functional pathology helps to guide the treatment decision-making process. In the case of muscle tension or tightness, Table 29.3 shows what specific treatments are appropriate for each different type of dysfunction.
Clinical Application
Manually resisted techniques are a perfect bridge into active care because they take place in the treatment room with the doctor’s guidance and instruction. When performing MRTs, it is helpful to realize that whereas historically there are many names (PNF, MEP, PIR, etc.) for different techniques, there are certain common elements to successful MRT application. MRTs involve isometric, concentric, or eccentric contractions. They are used to relax muscles, stretch muscles or fascia, mobilize joints, or facilitate muscles. The clinical indications for MRTs are summarized in Table 29.4.
MRTs may be used to relax tension in muscles before thrust manipulation. However, if we desire to stretch chronically shortened muscles or fascia, then chiropractic adjustments should precede any aggressive stretching. After an adjustment, MRTs can be used to reinforce neuromuscular reeducation and to instruct the patient for effective home exercise.
MRTs require active patient participation and are therefore less likely than passive modalities to encourage patient dependency. They are, however, more
demanding of the patient. The use of RI or gentle PIR methods is nearly always painless and, with a little patient education, simple to perform.
demanding of the patient. The use of RI or gentle PIR methods is nearly always painless and, with a little patient education, simple to perform.
Table 29.4 Manual Resistance Technique Goals (Indications) | |
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As compared to deep tissue massage (i.e., Graston technique), TrP therapy (Nimmo, myotherapy, or receptor tonus), or active release technique (ART), MRTs can be a faster and less painful way of reducing increased muscle tension or normalizing TrPs or muscle tension. Exceptions to this would be if the patient was either very uncoordinated or simply unable to relax. Patients with difficulty relaxing often need moist heat, relaxation, and breathing exercises, and some type of gentle, non-painful massage (i.e., effleurage). The combination of MRTs and soft tissue procedures can be used with great effect. For instance, as the tissues are being massaged, the patient can be instructed to first contract, then relax an area of tension to help release it. This combination can overcome even the most stubborn “knots.” The ART technique can easily be used in combination with MRTs to achieve a greater muscle inhibition.
Many times, if a patient cannot tolerate deep soft tissue manipulation (i.e., Rolfing or transverse friction massage), MRTs can be used to reduce the sensitivity of the area. After MRT application, deep massage or ischemic compression techniques will usually be more tolerable to the patient. It is important to note that any massage or passive therapy runs the risk of encouraging patient dependency. To reeducate and improve the coordination of the treated muscle, passive therapies should always be combined with some form of patient education, exercise, and self-treatment.
An alternative to PFS for musculo-fascial shortening is the osteopathic myofascial release method. This typically involves lifting the involved soft tissue and stretching it perpendicular to its muscle fiber orientation. This method is advantageous because it is thought to avoid engaging the stretch reflex. PFS, myofascial release, and deep tissue massage can complement each other, especially in recurrent and chronic conditions. Neuromuscular and chronic muscle shortening dysfunctions coexist and each component of the soft tissue dysfunction needs to be addressed in order to successfully resolve the patient’s symptom.
The use of hot packs, ultrasound, electrical muscle stimulation, and other passive thermal or electrical modalities is common in musculoskeletal clinical care. These are sometimes appropriate in acute and subacute care but are inappropriate in rehabilitation beyond the phase of early soft tissue healing. These passive modalities can be useful for preparing the tissues for more active manual techniques but the treatment regimen should be transitioned to active care as early as possible.
MRTs have the advantage that while being easily tolerated like passive modalities, they also involve the patient in an active way, thus limiting patient dependency. The thrust of modern management of chronic pain is away from passive therapy (physical agents) toward active patient involvement in the rehabilitation process (see Chapters 4 and 14). This does not mean that passive therapies do not have a role to play, but that we must aim our patients toward functional restoration in activities of daily living. MRTs are ideal bridges between passive and active care.
To summarize, MRTs are invaluable for normalizing pathologic barriers within joints and muscles. The pathologic barrier is identified as the point within the normal ROM of a joint or muscle where premature or increased resistance to motion is felt. The barrier may be caused by joint blockage, increased muscular tension, muscle shortening, or a combination of the three. MRTs help to eliminate this barrier and restore normal ROM. They achieve this by relaxing the overactive muscle and/or mobilizing the hypomobile joint. When true joint blockage exists, a chiropractic adjustment is without peer as the treatment of choice. MRTs can stand on their own but they can also complement to the adjustment and create a bridge to exercise.
Rules for Application
The more precisely we can facilitate contraction in the desired muscle fibers when using MRT, the better our results will be. Table 29.5 summarizes some of the keys to achieving successful facilitation. When the clinical goal is to relax a muscle, a moment’s attention to the patient’s overall relaxation through appropriate body positioning can greatly aid in the relaxation of the target muscle. Patient pre-positioning with respect to the specific target muscle will affect how easy or difficult it is to activate the muscle. Our verbal command is also important; not only in what we say but also in the tonal inflection we use. Trial and error with each patient will reveal which commands activate the desired movement best. In general, telling a patient to push to the right or left is not as good as giving them an actual tactile target. When using
facilitation techniques, it is helpful to place a contact on the muscle you wish to activate because manual contacts are facilitatory. Likewise, firm massage or goading while the patient attempts to contract the muscle may help to awaken a particularly inhibited muscle. Irradiation is sometimes used to facilitate a muscle, which is especially “dormant.” This involves using a synergistic muscle that is stronger to pull its inhibited neighbor into action.
facilitation techniques, it is helpful to place a contact on the muscle you wish to activate because manual contacts are facilitatory. Likewise, firm massage or goading while the patient attempts to contract the muscle may help to awaken a particularly inhibited muscle. Irradiation is sometimes used to facilitate a muscle, which is especially “dormant.” This involves using a synergistic muscle that is stronger to pull its inhibited neighbor into action.
Table 29.5 Facilitation Techniques | |
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Technique Principles
Patient positioning—the patient is placed in a position of maximum comfort and stability. The targeted muscle is placed in a position that allows a relaxed state. It is also placed in a position that is most advantageous for the recruitment of motor units of that muscle. The position of the patient and the treated muscle is such that the practitioner can maintain stability and control at all times. During patient positioning, the order in which the slack is taken up may improve isolation of the target tissue (e.g., flexion, contralateral side bending, and ipsilateral rotation for the upper trapezius). This is called “winding-up” the muscle.
Engaging the barrier—the muscle should be elongated to the extent to which the full resting length is attained. The barrier is the point at which further lengthening would cause the muscle to go into a stretch reflex. It is important to carefully engage this barrier and not go beyond it.
Use of isometric contraction—the isometric contraction is either very gentle or hard, depending on whether the condition being treated is neuromuscular hypertonus (e.g., TrPs) or muscle tightness with connective tissue involvement. A good rule of thumb is “as little force as possible or as much as necessary.” The duration of the contraction is usually 7 to 10 seconds. This may be increased up to 30 seconds if little or no release is achieved with a shorter effort.8
Use of breathing and eye movements—most muscles become facilitated with inhalation and inhibited with exhalation. Also, certain muscles are facilitated when the eyes are moved in certain directions and are inhibited when the eyes move in the opposite direction. These physiologic reflexes can be used to maximize the effectiveness of the manual resistance procedures.
Feeling the release—after the isometric contraction is let go, the patient breathes out and engages in inhibitory eye movements; it is important to wait to feel for the tension in the muscle to release. It is at this point that the muscle should be slowly guided to lengthen. Guide the muscle until a new barrier is engaged, at which time a second isometric contraction is begun and the process is repeated.
When using MRTs, various guidelines help us to avoid irritating our patients. Care must be taken that related joints are not put in a position of strain (i.e., close packed position) during stretching. For example, when stretching the iliopsoas if the lumbar spine is allowed to extend too much, strain will occur in the low back. When stretching in the spinal column, it is also important to avoid uncoupled movements. For instance, in the cervical spine, proper coupling occurs when rotation and side bending occur in the same direction (spinous process toward convexity). In the lumbar spine, it is the opposite (unless the spine is flexed). In the neutral or extended positions, normal lumbar coupling takes place when rotation and side bending occur in opposite directions (the spinous process moves toward concavity). This is important to incorporate when mobilizing joints with MRTs, and when stretching muscles that require slack be taken out in what would be an uncoupled manner for the underlying spinal joints.
An example of an uncoupled joint position is the cervical side bending away and rotation toward an upper trapezius muscle being stretched. Because this might strain the cervical spinal joints, we stretch almost completely over the upper back and shoulder area, avoiding any contraction or strong stretching in the neck area. The way that we “wind-up” the upper trapezius will reduce the potential for neck strain. Full flexion with slight ipsilateral rotation would be taken out first, then gently we would side bend the neck away from the muscle, and then finally slack would be taken out of the upper back and shoulder regions to the barrier. The patient’s contraction would be only from the shoulder in the direction of elevation. During relaxation and stretch, we would take out the slack over the larger, more stable shoulder and avoid taking out slack in the neck, except perhaps in flexion. This illustrates a general rule in MRTs that we should relax or stretch over the largest, most stable, and least painful joint.65,66
Another principle is to avoid stretching related structures, such as nerve roots, if irritated.65,66 For example, the hamstrings should not be stretched if the sciatic
nerve is irritated. Similarly, femoral nerve irritation may contraindicate rectus femoris stretching and brachial plexus irritation may contraindicate scalene stretching. Any increase in radicular pain or symptoms, no matter how slight, strictly contraindicates these procedures. Finally, pregnancy of either the patient or doctor contraindicates use of the PFS technique. Table 29.6 summarizes these important safety tips during stretching.
nerve is irritated. Similarly, femoral nerve irritation may contraindicate rectus femoris stretching and brachial plexus irritation may contraindicate scalene stretching. Any increase in radicular pain or symptoms, no matter how slight, strictly contraindicates these procedures. Finally, pregnancy of either the patient or doctor contraindicates use of the PFS technique. Table 29.6 summarizes these important safety tips during stretching.
Table 29.6 Safety Rules | |
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How we “wind-up” the muscle, in other words, the order with which we take out the slack in the different planes of motion (rotation, flexion/extension, side bending), can dramatically alter where the patient feels the stretch.65 Playing with this variable allows for better isolation of the specific muscle fibers requiring treatment. Most people use too much force when they first begin to use MRTs. The forces used during MRTs should be light. Whether to adjust joints before or after MRTs is a common question. If there is a significant joint restriction in the pathway we are attempting to stretch through, then it is crucial to adjust first. Table 29.7 lists different ways to improve MRT results.
Specific Procedures
Post-isometric Relaxation One of the most useful MRTs is PIR. This is Lewit’s modification of the gentle, indirect isometric MEP, which the osteopaths applied to joints.8 It is also similar to HR. The main goal of PIR is relaxation (decontraction) of a hypertonic (contracted) or overactive muscle. This is the preferred method if the patient has difficulty relaxing or you simply want to use a “softer” approach until you gain the patient’s trust. It is ideal for TrPs,69,70 joint mobilization, muscle spasm, and increased neuromuscular tension.
PIR involves the following simple steps8:
Position the patient appropriately for the muscle to be treated. Ensure that the patient is comfortable, fully supported, and at rest.
Table 29.7 Ways to Maximize Manual Resistance Technique Results
1) “Wind-up” muscles to maximize isolation
2) Start gently and add force only if necessary
3) Increase contraction time up to 30 seconds
4) Adjust restricted joints first
Passively lengthen the target muscle to the point at which the first slight increase in resistance (pathologic barrier) is felt while stabilizing the muscle’s proximal bony attachment. Avoid bouncing.
Have the patient gently contract the overactive muscle with minimal effort for approximately 10 seconds. This is resisted with equal counterforce creating an isometric contraction. For most muscles, the patient should breathe in while contracting the muscle.
Have the patient breathe out, “let go,” and relax the muscle fully.
The doctor pauses momentarily and monitors for a decrease in resistance felt at the barrier.
The muscle is gently, passively lengthened until a new barrier is felt if resistance decreases. If no decrease in resistance is felt, the procedure is repeated at the same barrier and any of the described modifications may be used.
While remaining engaged at the barrier, three to five repetitions are performed per treatment session.
If relaxation is not achieved, try the following:
Ensure the patient breathes in during the contraction phase and exhales during the relaxation phase.
Increase the duration of contraction up to 30 seconds.
Increase the force or degree of isometric contraction.
Upon completion of three to five repetitions, have the patient contract the antagonist (RI) muscle that is rhythmically resisted in a pulsed manner by the practitioner.
Upon completion of the above, the patient should be instructed to perform active ROM exercise through the new range.Related posts:
Active Care: An Evidence-Informed Approach to Self-Care for Patients with Spine Pain
Pain Mechanism Classification System Overview and Focus on the Motor/Autonomic Mechanism
Programming From Rehabilitation to Performance
Rotational Sports and the Spine
The Resilience Model
Dynamic Variable Resistance Training
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