Soft tissues of the body include skin, muscle, ligaments, and tendons. Proper physical therapy management and treatment of soft tissue injuries begin with a comprehensive evaluation to determine the origin of dysfunction. With regards to the soft tissue structures of the body, a comprehensive evaluation must assess all of the systems that can possibly affect the soft tissues of our body. These systems include the neurological system and the musculoskeletal system. The purpose of this article will be to discuss some of the interventions available to physical therapists facing soft tissue dysfunction.
The Musculoskeletal System
Recent research is helping to classify muscles into one of two classification systems: global and local systems. Muscles that belong to the global system appear to be more involved in regional stabilization between the thoracic spine and upper extremities, or the pelvis and lower extremities. Muscles that belong to the local system perform more of an anticipatory role as they are more important in segmental control or intrapelvic stabilization.2
Muscles that support the spine are considered part of the local system and are anticipatory in nature. This include the transverse abdominus, the pelvic floor musculature, and the deep multifidus. Research is suggestive that other muscles are anticipatory in nature such as psoas, the quadratus lumborum, posterior fibers of internal oblique, the diaphragm, and the lumbar portions of lumbar longissimus and iliocostalis.2
Muscles that are considered part of the global system and are responsible for regional movement between the spine, the pelvis, and the extremities are external obliques, latissimus dorsi, serratus anterior, rectus abdominus, the gluteals, hamstrings, adductors, the pectorals, upper trapezius, and levator scapulae.
Function would be significantly compromised if the human body was not capable of mobility with rigidity. An intricate balance of stability and mobility must exist within the human body for movement to occur. The role of the physical therapist in evaluating the musculoskeletal system is to determine where the breakdowns between stability (form closure) and mobility (force closure) exist.
Treatments for Excessive Force Closure
When assessing the soft tissue structures of the spine, the physical therapist must identify the problems regarding force closure. Force closure refers to the intricate interaction between the local and global system and their ability to provide stability to joints but at the same time allow for the body to move freely in space with control and without injury. When there is too much force closure, there will be excessive compression within the system, causing rigidity without mobility. When there is too little force closure within a system, there will be insufficient compression within the system allowing instability to occur. Kendall et al simply state that when a muscle is short (through its passive connective tissue elements) or strong (contractile element) and its antagonist (opposing muscle group) is not, it will create “a position of deformity,” and when a muscle is long (passive elastic element) or weak (contractile element) and its antagonist is not, it will allow for “positions of deformity.” The mechanisms creating problems with force closure can be mechanical, chemical, or neurological. A comprehensive physical therapy evaluation is necessary to determine the exact cause of dysfunction so that a specific plan of care can be tailored to the patient’s needs. The following section will discuss effective interventions appropriate to utilize when force closure is considered excessive.
Dry Needling
According to the American Academy of Orthopedic Manual Physical Therapy (AAOMPT), “Dry needling is a neuro-physiological evidence-based treatment technique that requires effective manual assessment of the neuromuscular system. Physical therapists are well trained to utilize dry needling in conjunction with manual physical therapy interventions. Research supports that dry needling improves pain control, reduces muscle tension, normalizes biochemical and electrical dysfunction of motor endplates, and facilitates an accelerated return to active rehabilitation”.4
Dry needling results in positive treatment outcomes for patients when combined with other manual therapy treatments. When combined with manual therapy and exercise, dry needling has been proven to be an effective treatment for low back pain, whiplash, headaches, chronic pelvic pain, complex regional pain syndromes, and fibromyalgia. The effectiveness of a dry needling intervention is highly determined by the skill level of the clinician. Currently, there are only two physical therapy curriculums that offer entry level training in dry needling. These curriculums ultimately enable the clinician to palpate myofascial trigger points and then to use the needle as a palpation tool to appreciate changes in the firmness of those tissues requiring treatment.4
The primary goals of dry needling are to desensitize soft tissues, to restore motion and function, and to possibly induce a healing response in the tissue. These goals are achieved by:
- Releasing shortened muscles
- Removing the source of irritation by needling paraspinals muscles
- Promoting healing by triggering local inflammation
- Decreasing spontaneous electrical activity at trigger points.
The mechanical effects of dry needling abnormal muscles are thought to involve disruption of a dysfunctional motor endplate. It is plausible that accurately placing a needle provides a local stretch to the contracted muscle elements. Pistoning the needle up and down is done to elicit a local twitch response within the muscle, which is thought to deplete the muscle cell of its excessive acetylcholine, a neurotransmitter that facilitates muscle contraction and has been found in excess within trigger points.6
The exact mechanism of the formation of trigger points or myofascial tightness remains unclear. How dry needling actually eliminates these trigger points also remains unclear. Recent research by Shah et al (2005) notes that there is an increased concentration of substances (substance P, Bradykinin, interleukin-1, etc.) that intensify the response from nociceptors (pain receptors) located within trigger points and surrounding tissues. Shah also noted an immediate reduction in these pain substances following treatment by dry needling.6
Trigger point dry needling has been recognized by prestigious organizations such as the Cochrane Collaboration and is recommended as an option for the treatment of persons with chronic pain. Several clinical outcome studies have demonstrated the effectiveness of trigger point dry needling, however, questions remain regarding the mechanisms of needling procedures.4
Active Release Technique (ART)
The goal of ART is to restore optimal texture, motion, and function of the soft tissue and release any entrapped nerves or blood vessels. This is accomplished through the removal of adhesions or fibrosis in the soft tissues via the application of specific protocols. Adhesions can occur as a result of acute injury, repetitive motion, and constant pressure or tension. ART eliminates the pain and dysfunction associated with these adhesions. When adhesions form in soft tissues, they become stiffer, tighter, and shorter.8 The muscle cells lose the ability to eliminate waste materials and can become painful. The muscular tension created by adhesions may compress joints, causing neuropathy symptoms due to nerve compression. In an ART treatment, the provider uses his or her hands to evaluate the texture, tightness, and mobility of the soft tissue. Using hand pressure, the practitioner works to remove or break up the fibrous adhesions with the stretching motions generally in the direction of venous and lymphatic flow, although the opposite direction may occasionally be used.8
In the first three levels of ART treatment, as with other soft-tissue treatment forms, movement of the patient’s tissue is done by the practitioner. In level four, however, ART requires the patient to actively move the affected tissue in prescribed ways while the practitioner applies pressure. Involvement of the patient is seen as an advantage of ART, as people who are active participants in their own health care are believed to experience better outcomes.8 One disadvantage of ART regards the comfort of the patient when ART is being applied. Many of the techniques can be uncomfortable as the practioner attempts to tear adhesions within the muscle. Another question regarding the practicality of ART intervention and its perceived benefit is when it is used in the absence of trauma. Trauma is necessary for adhesions to develop in muscles. If a physical therapist is using ART on atraumatic tissues, minimal benefit should be expected for this intervention.
Strain & Counterstrain
The strain and counterstrain approach is an excellent intervention choice for acute soft tissue dysfunction because it is gentle, atraumatic, and can be used without contraindications. When using strain and counterstrain, the patients’ body is moved slowly in non-painful directions until the therapist identifies positions of decreased muscular tension, reported relief, and palpable trigger points.5 Dramatic changes in pain relief, range of motion, and muscular guarding can be achieved with strain and counterstrain when applied appropriately.
The mechanism of action regarding strain and counterstrain is not clearly understood, but it is thought to involve interaction between the body’s natural mechanoreceptors, the spinal cord, and the brain. Somatic dysfunction, i.e. trigger points, is directly related to how the brain perceives information from the body’s mechanoreceptors. For example, nociceptors are high threshold pain nerve fibers found in joint capsules, blood vessels, and articular pads. They can be stimulated by chemical changes (as with inflammation), increases in pressure (as with disc herniations), or subluxation of articular joints. When stimulated, nociceptors increase tone in muscles of their corresponding joints via tonic reflexgenic effects. Strain and counterstrain stimulates other mechanoreceptors, muscle spindles, and golgi tendon organs that, via their organic spinal cord and brain reflexes, cause inhibition of tonic muscles. The relaxation effect on tonic muscles allows the physical therapist to mobilize, stretch, or manipulate the affected joints and normalize the patient’s mobility. The following receptors in Table 1 play an important role in somatic dysfunction that is manifested with the tender point of strain and counterstrain.
Table 1: Articular Receptors
| TYPE | MORPHOLOGY | LOCATION | PARENT NERVE | FUNCTION |
| 1 | Thinly encapsulated globular corpuscles in 3-6 clusters |
Superficial layers of the joint capsule |
6-9u small and myelinated | Static and dynamic mechanoreceptors of low threshold and slowly adapting; Proprioceptive |
| 2 | Thickly encapsulated conical corpuscles in 2-4 clusters |
Deep layers of the joint capsule and fat pads |
9-12u medium and myelinated | Dynamic mechanoreceptors of low threshold and rapidly adapting; Kinesthetic |
| 3 | Thinly encapsulated fusiform corpuscles |
Intrinsic and extrinsic joint ligaments |
13-17u large and myelinated | Dynamic mechanoreceptors of high threshold and very slowly adapting; Acts as the joint counterpart to the Golgi tendon organ; Inhibits antagonistic muscles to the stretched ligament |
| 4 | Simple nerve endings found in plexi and individually |
Fibrous capsule, ligaments, fat pads, blood vessel walls, bone, periosteum |
2-5u very small and myelinated and <2u extremely small and unmyelinated |
Nociceptors of high threshold and non-adapting; Pain sensors |
Joint Mobilizations
Once a muscle has been released, a joint’s true mobility can be assessed. The neutral zone of a joint can be determined without influence from excessive force closure (myofascial compression/tension). Similar to strain and counterstrain, joint mobilizations and manipulation have been proven to inhibit muscular tension through reflexes between the spinal cord, muscle spindles, and golgi tendon organs. Joints that prevent mobility through articular restrictions often have varying degrees of directions limiting movement. Therefore, varying grades of joint mobilization are used by physical therapists depending on the acuteness or chronicity of restriction, irritability of the joint, or type of joint dysfunction. The following identifies the varying grades of joint mobilizations and their mechanism of action.
- Grade I: Activates Type I mechanoreceptors with a low threshold and respond to very small increments of tension. Activates cutaneous mechanoreceptors and thus decreases pain. Oscillatory motion will selectively activate the dynamic, rapidly adapting receptors, i.e. Meissner’s and Pacinian Corpuscles. The former respond to the rate of skin indentation and the latter respond to the acceleration and retraction of that indentation.
- Grade II: By virtue of the large amplitude movement, it will affect Type II mechanoreceptors resulting in inhibition of pain and reducing muscle tension or spasm.
- Grade III: Selectively activates more of the muscle and joint mechanoreceptors as it goes into resistance and less of the cutaneous ones as the slack of the subcutaneous tissues are taken up. Grade III begins to stretch joint capsules which allows for improved range of motion.
- Grade IV: With its more sustained movement at the end of range, Grade IV will activate the static, slow adapting, Type I mechanoreceptors, whose resting discharge rises in proportion to the degree of change in joint capsule tension.
- Grade V: This is the same as joint manipulation. High velocity thrust techniques break joint adhesions and allow for improved joint mobility, decreased pain, and promote normal muscle tone.
Neural Mobilizations
All soft tissues of the human body are connected in some way to the nervous system and the nervous system has complex biomechanics just like the structures it innervates. Nerves can be injured by mechanical, chemical, or physiological consequences of friction, compression, stretching, or disease. Traumas do not have to be severe injuries; they can be a result of repetitive muscle contraction, unphysiological movement, or body postures. There may not be a direct mechanism of injury to a nerve. Often nerve injury results from secondary injury to the nervous system as a result of blood or edema.
Neural mobilization is an intervention that has been around since the beginning of the century. In the late 1880’s, surgeons in France and England joined together to develop a tool called a “nerve stretcher.” A small incision was made in the patient’s gluteals region to expose the sciatic nerve. The “nerve stretcher” was then used to hook the sciatic nerve and pull it until it was exposed six inches above the skin. Fortunately for patients, the art of mobilizing the nervous system has become more delicate and refined over the years. Neural mobilizations now involve a delicate delivery of technique that involves many factors such as handling and palpation skills, patient communication, knowledge of biomechanics, and reassessment skills.
The nervous system adapts to movement in two ways:
- Tension and increased pressure is created as a consequence of elongation and occurs in all tissues and fluids enclosed by the epineurium and dura mater.
- Movement: In regards to the nervous system, movement must be broken down into two types: (a) gross movement, such as how the median nerve glides through the carpal tunnel (b) intraneural movement, refers to movement of neural tissue elements in relation to their connective interface. For example, the brain can move in relation to the surrounding cranial dura mater and the spinal cord can move in relation to the dura mater.
Physical therapists incorporate these adaptations of nervous system mobility into interventions for treatments in the presence of nerve injury. Intraneural scarring from swelling or mechanical compression from disc injury are only a few examples of pathology that can interfere with normal nervous system mobility. Nerve mobilizations afford physical therapists a way to increase movement of a nerve and at the same time provide enhanced nutrition to the nerve to promote pain relief, improve range of motion, and increase neural input into the tissues that the nerve innervates.
Neural mobilization techniques can be very powerful and care must be used by the physical therapist to identify worsening of symptoms from their patients. For example, in the presence of a large disc herniation, neural mobilization techniques will likely elicit painful symptoms and result in a poor treatment outcome for the patient. The key in using neural mobilizations is to focus on the word “mobilizations,” not “stretch.” This way, the physical therapist will focus their treatment on the resistance of the nerve glide and not depend on patient feedback, ensuring that nerve irritation will not result from the intervention.
Treatments for Inefficient Force Closure
The key components for promoting force closure are to:
- “Wake up” and coordinate the deep and superficial systems
- Functional, new strategies for posture and movements based upon the patient’s specific needs
Core training for any individual suffering from or recovering from spine injury must involve activation of the deep musculature system: pelvis floor, transversus abdominus, and multifidus. Research has shown that individuals capable of isolating their deep musculature system have a decreased incidence of recurrence of back pain. Hodge’s research determined that the deep musculature system does not contract to stiffen the spine but instead responds in a coordinated manner to balance the flexion and extension forces acting on the spine, which in turn provides an appropriate strategy for the body to ensure dynamic stability or, as Hodges describes, “mobility without rigidity.”
Patients following trauma, surgery, or injury to their spine often lose the ability to efficiently activate their core muscles and thus develop inefficient strategies to provide proper force closure. Physical therapists possess many tools (taping, electrical stimulation, bracing, diagnostic ultrasound…etc.) and strategies to retrain proper core control and must make this a beginning part of any stability program that their patients enter.
Proprioceptive Neuromuscular Facilitation (PNF)
PNF is a philosophy of treatment that incorporates the body’s sensory receptors, nerves and muscles, and functional movements into an exercise program tailored to a patient’s specific needs. Once the patient identifies how to properly recruit their deep core musculature system, the physical therapist must retrain the patient on how to incorporate this core control into functional movements. Using PNF as an intervention involves the therapist providing manual contact, resistance, or facilitation through a desired functional pattern of movement. The therapist may change their contact, resistance, speed, or verbal cues during the exercise to train the patient’s proprioceptive awareness. With repeated practice and training, the patient’s brain and nervous system adapts to the movements with improved strength, awareness, and anticipation, thus making them less likely to re-injure themselves as they return to their sport or activities of daily living.
PNF incorporates the patient’s visual system, timing, natural reflexes to stretch, traction, and joint compression to promote stability, increased strength, and facilitate coordination between the trunk and the extremities. The goal of PNF is to promote functional movement through facilitation, inhibition, strengthening, and relaxation of muscle groups, creating the ultimate balance of force closure.
PNF Stretching Techniques
Contract-relax is a PNF relaxation technique that uses the body’s natural stretch reflex to increase range of motion. Following the contraction of the muscle, the local muscle spindle relays information through the spinal cord to the brain that the muscle is being shortened. Reflectively, the brain relays message via gamma neurons to the shortened muscle to relax. A skilled physical therapist can feel this relaxation and follow with a gentle stretch to improved flexibility. Likewise, a skilled physical therapist can use the same reflex to facilitate contraction of a muscle. By providing a quick stretch to a muscle, the muscle spindle then relays information that it is being stretched too far and, in return, the brain relays a signal for the muscle to contract. By using PNF in this manner, the physical therapist is able to facilitate muscle activation and improve the patient’s ability to contract a muscle.
PNF Strengthening Techniques
Along with stretching, PNF strengthens the body through diagonal patterns, often referred to as D1 and D2 patterns. It also applies sensory cues, specifically proprioceptive, cutaneous, visual, and auditory feedback to improve muscular response. The diagonal movements associated with PNF involve multiple joints through various planes of motion. These patterns incorporate rotational movements of the extremities but also require core stability if patients are to successfully complete the motions.
Two pairs of diagonal patterns exist. These patterns can be performed in flexion or extension and are often referred to as D1 flexion, D1 extension, D2 flexion or D2 extension techniques for the upper or lower extremity. Although patients can perform these patterns with many forms of resistance, the interaction between patient and clinician is critical to early success of PNF strengthening.
This interaction requires manual resistance throughout the range of motion through carefully positioned hand placement and appropriately choreographed resistance. By placing the hands over the agonist (primary mover) muscles, the clinician applies resistance to the appropriate muscle group while guiding the patient through the proper range of movement.
Using manual resistance, the clinician can make minor adjustments as the patient’s coordination improves or fatigue occurs during the rehab session. In general, the amount of resistance applied is the maximum amount that allows for smooth, controlled, pain-free movement throughout the range of motion. In addition to manual resistance strengthening, PNF diagonal patterns enhance proper sequencing of muscular contraction, from distal to proximal. This promotes neuromuscular control and coordination.13
Conclusion
The first step for success in rehabilitation starts with accurately assessing the problems in form and force closure and accurately identifying the pathology responsible for a patient’s dysfunction. The second step is choosing the best intervention to promote wellness. The above techniques are only a few methods used by physical therapists to treat soft tissues dysfunction and were chosen because they are the most commonly used and have been supported by evidence-based research. It is important to note that rarely is one technique by itself effective for complete resolution of a patient’s pain. The more skilled interventions a physical therapist has to choose from to treat their patients, the more successful they will be regarding their patient outcomes. Patients suffering from chronic or acute soft tissue dysfunction and in need of physical therapy should seek practitioners that have experience with many of the above mentioned techniques to ensure the best prognosis for a successful nonsurgical outcome.
Richard Banton, DPT, CMPT, ATC
Virginia Therapy & Fitness Center
References
[1] Bermark A 1989 Stability of the lumbar spine. A study in mechanical engineering. Acta Orthopedica Scandinavica 230(60): 20
[2] Lee DG 1997b Treatment of pelvic instability. In Vleeming A, Mooney V, Dorman T, Snijders C, Stoeckart R, Movement, stability and low back pain. Churchhill Livingstone, Edinburgh, p 445
[3] Lee Diane 2004 The Pelvic Girdle 3rd edition ChurchHill Livingstone, Edinburgh, p 45-47
[4] Kendall F, McCreary E, Provance P. Muscles: Testing and Function. 4th ed. Baltimore, Md: Williams & Wilkins; 1993.
[5] Dommerholt J. Trigger Point Dry Needling, The Journal of Manual and Manipulative Therapy: 2006 Vol. 14 (4) 70-87
[6] Zylstra ED, Kinetacore (GEMt-US). The Management of Neuromuscular Dysfunction Intramuscular Manual Therapy/Trigger Point Dry Needling: Introduction to Applications for Pain Management and Sports Injuries. P 39-40.
[7] Langevin, H. M.,Churchill, D. L., Cipolla, M. J. Mechanical signaling through connective tissue: a mechanism for the therapeutic effect of acupuncture. FASEB J. 15, 2275–2282 (2001)
[8] Shah JP, Phillips TM, Danoff JV, Gerber LH. An in vivo microanalytical technique for measuring the local biochemical milieu of human skeletal muscle. J Appl Physiol 2005; 99:1980-1987.
[9] Leahy PM. Active release techniques soft tissue management system, manual. Colorado Springs: Active Release Techniques, LLP, 1996:51-56
[10] Clark, RK, Wyke, BD. “Temporomandibular articular reflex control of the mandibular musculature.” International Dental Journal. 1975 Deb 25 (4):289-96.
[11] Sung, P.S., Kang, Y. Pickar, J.G. 2005. Effect of spinal manipulation duration on low threshold mechanoreceptors in lumbar paraspinals muscles. Spine 30 (1), 115
12 Maitland, G.D. Peripheral Manipulation 2nd ed. Butterworths, London, 1977.
[13] Butler, D. Mobilization of the Nervous System ChurchHill Livingstone, Edinburgh, p 56-57
[14] Cavafy, J 1881 A case of sciatic nerve stretching in locomotor ataxy: with remarks on the operation. British Medical Journal Dec 17; 973-974.
[15] Butler, D. Mobilization of the Nervous System ChurchHill Livingstone, Edinburgh, p 36-37
[16] Lee Diane 2004 The Pelvic Girdle 3rd edition ChurchHill Livingstone, Edinburgh, p 323
[17] Hodges PW, Richardson CA 1996 Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominus. Spine 21 (22): 2640
[18] Hodges PW, Richardson CA 1996 Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominus. Spine 21 (22): 2640
[19] Adler S, Beckers D, Buck M. PNF in Practice An Illustrated Guide. Springer-Verlag, Berlin, p 10-25.
[20] Beattie PF, Arnot CF, Donley JW, Noda H, Bailey L, J Ortho Sports Physical Therapy 2010; 40(5): 256-264
[21] Aure OF, Nilsen JH, Vasseljen O, Spine 2003; 28(6): 525-531
[22] Wand BM, Bird C, McAuley JH, Dore CJ, MacDowell M, De Souza LH, Spine 2004; 29(21): 2350-2356
