Effects of Myofascial Release Leg Pull and Sagittal Plane Isometric Contract-Relax Passive Straight-Leg Raise Angle

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1 , ;.,-... R. *..d->.c'.h ' S T U D Y ,.. Effects of Myofascial Release Leg Pull and Sagittal Plane Isometric Contract-Relax Passive Straight-Leg Raise Angle William P. Hanten, EdD, PT' Sandra D. Chandler, MS, PTZ M aintaining or improving joint range of motion (ROM) is often a goal of the physical therapist for promoting the health and quality of a patient's life. Primary sources of resistance to normal passive ROM are the joint capsule, musculotendinous tissue, and skin (10). These components can be affected by different manual techniques used in the clinic to improve ROM. Techniques that have been studied and shown to be effective in improving hip flexion ROM are proprioceptive neuromuscular facilitation (PNF) hold-relax and contract-relax, sagittal plane isometric contract-relax, and passive stretch (8,9,13,14,18,21,23). Techniques that have not been studied but that have been claimed to improve ROM are myofascial release techniques (17). These are manual techniques used in the clinical setting to mobilize soft tissues of the body. Anecdotal claims of their effectiveness in releasing painful connective and muscle restrictions have provoked controversy among clinicians due to an absence of scientific experimental research to validate these claims (17). In theory, this form of releasing restrictions mav improve functional ROM and, when used either alone or as an adjunct to Experimental evidence does not currently exist to support the claims of clinical effectiveness for myofascial release techniques. This presents an obvious need to document the effects of myofascia1 release. The purpose of this study was to compare the effects of two techniques, sagittal plane isometric contract-relax and myofascial release leg pull for increasing hip flexion range of motion (ROM) as measured by the angle of passive straight-leg raise. Seventy-five nondisabled, female subjects years of age were randomly assigned to contract-relax, leg pull, or control groups. Pretest hip flexion ROM was measured for each subject's right hip with a passive straight-leg raise test using a fluid-filled goniometer. Subjects in the treatment groups received either contract-relax or leg pull treatment applied to the right lower extremity; subjects in the control group remained supine quietly for 5 minutes. Following treatment, posttest straight-leg raise measurements were performed. A one-way analysis of variance followed by a Newman-Keuls post hoc comparison of mean gain scores showed that subjects receiving contract-relax treatment increased their ROM significantly more than those who received leg pull treatment, and the increase in ROM of subjects in both treatment groups was significantly higher than those of the control group. The results suggest that while both contract-relax and leg pull techniques can significantly increase hip flexion ROM in normal subjects, contract-relax treatment may be more effective and efficient than leg pull treatment. Key Words: myofascial, contract-relax, straight-leg raise ' Professor, School of Physical Therapy, Texas Woman's University, 1130 M. D. Anderson Blvd., Houston, TX Staff Physical Therapist, Outpatient Physical Therapy Dept., Quentin Mease Community Hospital, Harris County Hospital District, Houston, TX This study was approved by a Texas Woman's University Human Subjects Review Committee. other treatments, may expedite return to full ROM after injury. In classical PNF, the limb is moved to the point where limitation is felt. The passive stretch is then held in a PNF pattern while the subject either isometricallv "holds" (hold-relax) the position against the therapist's resistance to the antagonist or isotonicallv contracts the an- tagonist (contract-relax) against resistance of the therapist, who allows rotation only to occur while stabilizing against movement in the sagittal and frontal planes (26). Several studies have examined the effects of these PNF techniques on hip flexion ROM as measured bv passive straight-leg raise. Tanigawa (23) found PNF hold-relax to be more ef-

2 fective than passive stretch in increasing passive straight-leg raise angle in subjects with limited hip flexion. Markos ( 1 3) compared PNF hold-relax with PNF contract-relax and found that both were effective in increasing passive straight-leg raise angle, although PNF contractrelax was significantly better. Other authors have not used classical PNF definitions of contractrelax but have modified the technique to include isometric contractions in a sagittal plane only (9,14,18). In sagittal plane isometric contract-relax, maximal passive stretch of the antagonist to the tolerance of the subject is induced in the sagittal plane and then held while the subject isometrically contracts the stretched muscle against resistance given by the therapist, who does not allow rotation. Sagittal plane isometric contract-relax was found by Medeiros et al (14) to be equally effective as passive stretch in significantly increasing passive straight-leg raise angle. Studies by Holt et al (9) and Sady et al (18). however, found sagittal plane isometric contract-relax to be more effective in increasing passive straightleg raise angle than passive stretch. Myofascial release is a system of manual therapy involving massage and stretching techniques that are advocated to cause changes or "releases" in restricted or pathological fascial structures. Definitions and putative mechanisms of "release" do not appear to be based on any objective measurable criteria. A "release" is defined by Upledger and Vredevoogd (25) and Manheim and Lavett (1 2) as a "softening" or "letting go" when resistance melts and the tissue is felt to relax and elongate. According to Manheim and Lavett (1 2). the elongation helps alleviate impediments to normal movement. Myofascial release techniques can involve direct superficial or deep pressure at the point of restriction or low-load prolonged gentle distraction of restricted tissues (1,4,12,24). All techniques proceed according to "releases" felt by the therapist from the addressed tissues. The myofascial release technique of leg pull, as described by Manheim and Lavett (1 2). is a low-load prolonged distraction or pulling of the leg by the therapist in a pattern of circumduction at the hip, which causes gentle elongation of muscle contractile elements and inert structures. The pattern of motion is stilled at the slightest soft tissue restrictions until release is felt before the motion proceeds (1). Moving the lower extremity in a pattern of circumduction attempts to eliminate Myofascial release is a sysfem of manual therapy involving massage and sfrefching techniques which are advocated to cause changes or "releases" in restricted or pa fhological fascial sfrucfures. fascial restrictions in all planes of movement (1 2). There is no scientific evidence to substantiate that leg pull is effective in elongating muscle or eliminating fascial restrictions. It is unknown whether the load produced by leg pull is of sufficient duration to improve ROM, but there is evidence that low-load, prolonged stretch techniques are more effective than high-load brief stretch techniques in elongating inert tissues (1 1,27). In a study by Warren and Lehman (27), low-load prolonged stretch produced more residual elongation in tendons than high-load brief stretch. Light et al (1 1) re- ported that low-load prolonged stretch was more effective in treating knee flexion contractures or inert structures than high-load brief stretch. Myofascial release techniques are used often in clinical settings to treat myofascial dysfunction, but virtually no scientific experimental evidence exists to support claims of clinical effectiveness (2.17). There is a need to document the effects of myofascial release techniques in controlled studies (3.1 7). The purpose of this study was to compare the effects of leg pull with those of sagittal plane isometric contract-relax on hip flexion ROM as measured by passive straight-leg raise. The following null hypothesis was tested: no significant difference exists among groups of subjects receiving sagittal plane isometric contract-relax, leg pull, and no treatment in changing hip flexion ROM as measured by passive straight-leg raise. METHOD Sub jeds Subjects were 75 nondisabled, female volunteers between the ages of 18 and 29 years (% = 24.4, SD = 2.5). They read and signed an institutionally approved informed consent form. Subjects denied any recent history of musculoskeletal or neurological pathology of the back, pelvis, or lower extremities. In order to have subjects with some degree of reversible soft tissue limitation in hamstring extensibility, only nondisabled females with 75" or less of passive straight-leg raise were used. They showed no more than 20" hip flexor tightness as determined by a Thomas test. Equipment The angle of straight-leg raise for each subject was measured using a fluid-filled goniometer scaled to JOSPT Volume 20 Number 3 September 1994

3 1 ". Hip flexor tightness was measured using a two-arm plastic goniometer with 12-inch arms scaled in 1 " increments. A quadriceps board was used to assist in stabilizing the nonexperimental lower extremity of each subject and to secure it in 20" of hip flexion. Procedure Subjects were randomly assigned to one of three groups: two treatment groups and one control group. Each group consisted of 25 subjects. One treatment group received contract-relax; the other received leg pull. One investigator administered both techniques and performed all measurements. The investigator was a physical therapy student with formal training in myofascial techniques and 11 months of practice with the techniques and measurements used in this study. Each subject was measured for hip flexor tightness. Because the lower extremity was to be stabilized in 20" of hip flexion to affix the pelvis in a neutral position while a straight-leg raise test of the other lower extremity was performed, no more than 20" of left hip flexion was allowable. While positioned supine on the plinth, the subject drew both knees to her chest. She then held one knee in place, allowing her other leg, with knee extended, to drop slowly to the plinth. The amount of hip flexor tightness in the hip was measured to the nearest degree. Any subject who exhibited tightness of over 20" was excluded from the study. Reliability of the investigator's straight-leg raise measurements was then established on the subject's left limb using the following procedure. A quadriceps board was secured to the table using two straps. The subject lay supine on the plinth as her right thigh and leg were strapped onto the quadriceps board, using one strap each to position the right hip in 20" of flexion. Her pelvis was stabilized by one strap placed across her pelvis between the anterior superior iliac spine and anterior inferior iliac spine. The fluid-filled goniometer was attached to her left thigh, 10 cm proximal to the lateral femoral condyle on a line between the femoral condyle and greater trochanter. After recording the goniometric reading to the nearest degree unit at starting position (left knee extended, left hip in neutral rotation, limb resting on the plinth), a passive straight-leg raise was performed by slowly lifting her left lower limb at the posterior ankle. The lifting stopped when the endpoint of hamstring tightness was reached. The endpoint was determined by one or both of two criteria: 1) a contraction in the quadriceps muscle as palpated Total treatment time depended on the number and nature of restrictions encountered. by the investigator's hand or 2) knee flexion. The subject was instructed not to allow her back to break contact with the plinth during the procedure; her lower back position was checked with the experimenter's hand before lifting began. At the endpoint, the goniometer was read, and the limb was lowered back to the plinth. All subjects were measured twice, and an intraclass correlation (ICC 1,l) coefficient was determined. The resulting coefficient was.91. Following the procedures and measurements used to determine reliability, a pretest straight-leg raise measurement of the right lower limb was taken for each subject. The quadriceps board was moved to sup port the left hip in 20" of flexion, with the limb stabilized as previously described. The fluid-filled goniometer was strapped to her right thigh, and the straight-leg raise test was performed as previously described using one trial per subject. Any subject whose ROM exceeded 75" of hip flexion was excluded from the study. Each subject receiving the contract-relax treatment remained positioned on the plinth after the pretest with her left lower extremity secured to the quadriceps board. With her right posterior ankle resting on the investigator's right shoulder and her knee extended, her hip was flexed by the investigator's shoulder lifting the leg. The lifting stopped when the investigator detected an endpoint. The subject was instructed to maximally contract her hamstrings, pushing statically against the investigator's shoulder for 7 seconds while her hip was maintained in the flexed position. The subject was then instructed to relax for 5 seconds. During this relaxation period, the investigator repositioned the subject's leg to the new point of hamstring tightness. The contraction followed by relaxation/repositioning procedure was repeated twice, for a total of three repetitions. The subject's limb was then lowered to the plinth, then raised to the new endpoint during a 1 0-second rest period. This completed one cycle of contractrelax. Four more cycles were performed for a total of five cycles. Total treatment time was 4 minutes. During the last 1 0-second rest period, the leg was lowered to the plinth, where it remained for 2 minutes. After the 2-minute period, the straight-leg raise posttest, as described previously, was performed. Each subject in the leg pull treatment group had the quadriceps board and pelvic straps removed after the right leg pretest straight-leg raise measurement was taken and laid supine on the plinth with both legs extended. The investigator cupped the subject's right heel with the right hand while dorsiflexing the

4 same foot with the left hand. After moving the foot to a neutral position, gentle traction was placed on the leg until a release was felt. Any slack was taken up with continued gentle traction. The leg and hip were then gently externally rotated until tightness was felt by the investigator; the investigator then internally rotated the leg and hip a few degrees, held, and waited for a release before continuing external rotation. The investigator maintained gentle traction until full external rotation was achieved. Slowly, the tractioned, externally rotated leg was moved into abduction, adducting a few degrees at any points of tightness and waiting for release before proceeding into full abduction. With continued traction, the externally rotated and abducted leg was allowed to flex at the hip so that it was moved upward into the sagittal plane with the foot toward the ceiling. Movement of the leg by the investigator proceeded into full adduction. with the hip flexed, across the subject's midline until she rolled over onto her left side. Throughout this circumduction, tightness was met with a reversal of the circumduction a few degrees to wait for release before proceeding. With the subject sidelying on her left side, the investigator then repositioned the right foot to place the leg and hip in internal rotation and the circumduction pattern of movement previously described was reversed until the subject was supine with her right leg beside her left leg. Again, traction and internal rotation of the leg were maintained throughout the entire circumduction motion. Whenever tightness was encountered, the protocol of reversing a few degrees and waiting for a release before proceeding was observed. Total treatment time depended on the number and nature of restrictions encountered, but the average time was 10 minutes and never exceeded 15 minutes. At the conclusion of leg pull treatment, the subject remained supine on the plinth while her left lower extremity was strapped to the quadriceps board and her pelvis was secured to the plinth, which took approximately 2 minutes. A straight-leg raise posttest, as described previously, was then performed. Subjects in the control group remained supine on the plinth quietly for 5 minutes after the pretest, at which point the posttest straight-leg raise was performed. Data Analysis Means and standard deviations for the pretest, posttest, and gain scores of each group were calculated. To determine whether a significant difference existed between A possible reason for range of motion gains from using contracfrelax is the neurogenic relaxation of muscle brought about by its voluntary con fracfion. the mean gain scores of each group, a one-way analysis of variance was utilized at a 0.05 alpha level. After obtaining a significant F value, Newman-Keuls post hoc comparisons were conducted to specify how the groups differed from each other. RESULTS Calculated means and standard deviations for group pretest, posttest, and gain scores are shown in Table 1. The greatest average straight-leg raise angle increase occurred in the contract-relax group (10.4") compared with the leg pull group (6.6") and control group (0.9"). A one-way analysis of vari- ance of the gain scores, as shown in Table 2, revealed a significant difference between the groups. A Newman-Keuls post hoc analysis showed that both contract-relax and leg pull group means were significantly different ( p <.05) from the control group and from each other. DISCUSSION Subjects who received the contract-relax treatment increased hip flexion ROM (as measured by a passive straight-leg raise test) significantly more than those who received leg pull treatment. The increase in straight-leg raise angle of subjects in both treatment groups was significantly higher than that of the control group. Direct comparison of hip flexion ROM gains obtained from contract-relax subjects in this study with those of contract-relax or PNF subjects in other experiments is only possible in a general way due to differences in planes of movement, types of resistance, duration of treatment, gender of subjects. ROM measurement methods used, and time intervals between pre- and posttest measurements. Contract-relax, Group Pretest Pattest Gain Contract-relax (N = 25) (5.7) (7.4) (4.6) Leg pull (N = 25) (5.3) (6.7) (4.1) Control (N = 25) (5.2) (4.8) (1.8) TABLE 1. Pretest, posttest, and gain score means (in degrees) and standard deviations of angle oi straightleg raising for experimental and control (no treatment) groups. Source SS df MS F Groups ' Error Total p <.05. TABLE 2. One-way analysis of variance. JOSPT Volume 20 Number 3 September 1994

5 chosen in this study as a comparison technique, was selected for its effectiveness in improving ROM (9,14,18) and for its simplicity as a treatment; ie., it is easy to administer without extensive training. Despite differences in technique, ROM gains obtained by our contract-relax subjects are similar to results of previous experiments. Applying contract-relax for 7 minutes per day for 8 days, Medeiros et al (1 4) reported a mean increase in straight-leg raise angle of 7.3". Tanigawa (23), using PNF hold-relax technique for approximately 1 minute, reported a straightleg raise angle mean gain in his subjects of 7.6". Markos (1 3) applied PNF contract-relax to subjects for approximately 1 minute and reported a mean gain in straight-leg raise angle of 20.5", whereas the PNF hold-relax group mean gain was 8.8". The contract-relax group straight-leg raise mean gain score of 10.4" found in this study is slightly higher than that reported by Medeiros et al (14). Subjects in that study, although receiving a longer treatment over numerous sessions, were not instructed to maximally contract the resisted muscle as were the subjects in this study. Additionally, Medeiros et al(14) did not evaluate their subjects for initial hamstring tightness, possibly limiting the potential increase in straight-leg raise angle after treatment. Markos (1 3) found a straight-leg raise mean gain score in her PNF contract-relax group that was approximately twice that of this study and over twice that of her PNF hold-relax group. The rotational movement allowed in the PNF contract-relax technique has been postulated to increase muscle relaxation (1 9,26). Markos (1 3) suggests that this may explain why she found a higher straight-leg raise gain in her PNF contract-relax group than in her PNF hold-relax group, which did not allow rotational movement. Contract-relax also does not allow rotational movement so that subjects in this group, like those undergoing PN F hold-relax, could not benefit from any potential rotation-related relaxation effects on ROM. This may account for the higher straight-leg raise gain of the PNF contract-relax group in the Markos (1 3) study compared with that of the contract-relax group in the present study. The higher gain scores of the contract-relax group in the present study over those of PNF hold-relax groups in studies by Tanigawa (23) and Markos (1 3) may be accounted for by the longer contract-relax treatment time. Two primary reasons have been proposed to explain why contract-relax increases ROM. The first involves passive stretching of soft tissue during the "relax" or stretching phase of contract-relax. In the absence of structural pathology, ROM at a joint is limited primarily by muscles and their surrounding fascia, tendons, and ligaments. Several studies have demonstrated that some tissue lengthening occurs due to applying passive stretch to the joints of nondisabled subjects (1 4,23) and subjects with pathological soft tissue limitations (1 1). A second possible reason for ROM gains from using contract-relax is the neurogenic relaxation of muscle brought about by its voluntary contraction. Autogenic inhibition of a motor neuron pool's excitability may be instigated by the contraction of its muscle, which stimulates inhibitory receptors in that muscle, causing it to relax (5,7.13,16,23). The H-reflex is hypothesized to be an indirect measure of the excitability of the motor neuron pool (5.16). Moore and Kukulka (1 6) and Etnyre and Abraham (7) showed H-reflex amplitude depression in motor pool excitability of the soleus immediately after its contraction, suggesting that contract-relax was reflexively inhibiting muscle activity. Moore and Kukulka (1 6) hypothesized that although numerous neurological mechanisms are possi- ble, presynaptic inhibition is the most likely reason for the inhibition. Surface electrode electromyographic (EMG) activity has also been used to study postcontraction neurogenic effects on a muscle (5,15). Electromyographic activity in a muscle undergoing contract-relax should decrease during the relax phase if a neurological mechanism has operated to inhibit the muscle (15). Moore and Hutton (15) showed that EMG activity levels actually increased during the relaxation phase of contract-relax and, therefore, did not support this hypothesis. Condon and Hutton (5) reported increased EMG activity levels along with decreased H-reflex activity levels in the same muscle during the relax phase of contractrelax. Etnyre and Abraham (6) suggest that the apparent conflict between H-reflex and EMG activity levels in a muscle postcontraction may be resolved by examining EMG activity levels from intramuscular electrodes. Etnyre and Abraham (6) hypothesize that artificially high surface electrode EMG activity level of earlier studies during the relax phase of contract-relax may have been due to "cross-talk" between electrodes from nearby muscle groups. Leg pull resulted in significant straight-leg raise angle gains for nondisabled subjects compared with the control group, but the technique did not prove as effective as contractrelax for improving ROM. The mechanisms by which myofascial release works are unsubstantiated. Shea (20) theorizes about a piezoelectric effect produced when pressure is applied to the molecular crystalline lattices that he maintains are in myofascial tissue. Ground substance in extracellular space becomes gelled when injured fascia shortens and dehydrates. But with pressure or stretch, the piezoelectric effect can increase the electrical potential of this tissue to rehydrate the ground substance (20). This ground substance, or proteoglycan, provides lubrication for connective tissue and

6 maintains distance between fibers (22). The idea that applying pressure or stretch to injured tissue can create an environment for connective tissue to move without restriction is implied. Myofascial release techniques are claimed to cause vasomotor response, increase blood flow to affected areas, increase lymphatic drainage of toxic metabolites, realign fascia1 planes, influence the proprioception of affected soft tissue (4), alleviate musculoskeletal pain and dysfunction (24). and restore functional ROM in areas of painful restriction (4). These claims are not supported by experimental research. Considering that myofascial release is thought to hydrate dehydrated ground substance of injured tissue and restore functional ROM to areas of painful restriction, perhaps optimal ROM effects can only be expected on subjects with pathologic tissue. Subjects in this study, although selected for hamstring tightness, were not considered to have pathology since their tightness did not interfere with daily activities, was not painful, and could not have been caused by pathologically affected tissues. Greater ROM gains for leg pull might have been seen in subjects with painful restriction. The duration of treatment for subjects in the leg pull group ranged from 7.3 to 14.3 minutes, depending on the number of restrictions encountered by the investigator and the amount of time before a "release" was felt at each restriction. The amount of increase in straightleg raise angle for each subject was not related to the length of time leg pull was applied, as shown by a Pearson's correlation coefficient of -.23 (p <.05). The low, negative correlation suggests that for leg pull subjects, longer treatment time cannot be expected to result in increased straight-leg raise angle. Straight-leg raise angle generally measures hamstring length, which may be most affected by release of restrictions while the leg is held in the sagittal plane. The amount of time the investigator held each subject's leg in the sagittal plane during the leg pull bout was not measured, and it is possible that straight-leg raise angle gains are related to this duration. If this is the case, then it may be argued that this technique is merely an elaborate form of traditional passive stretch. Indeed, leg pull group results in this study compare favorably with passive stretch group results in studies comparing passive stretch with PNF techniques in which straight-leg raise angle gains for passive stretch were less than for PNF (9,18,23). Bias may have occurred in this study because this study was not set up to be blind. A blinded measurement of the angle of passive straight-leg raise would have prevented bias based on the investigator's knowledge of the group to which the subjects belonged. The contract-relax group yielded greater straight-leg raise angle gains in less treatment time than the leg pull group. Thus, it is certainly more efficient. Contract-relax treatment was also easier for the investigator when compared with leg pull treatment in which the investigator became fatigued after maintaining traction and support of the subject's leg in all planes for up to 15 minutes. Although longer leg pull treatment duration may yield greater straight-leg raise angle gains, investigator fatigue and the obvious advantages of contract-relax make this a moot option. Based on these criteria, clinicians may prefer contract-relax over leg pull for increasing straight-leg raise angle in nondisabled persons. However, the mean difference of 3.8" between the two groups might not be clinically significant. This study examined only immediate posttreatment effects of leg pull and contract-relax treatments on straight-leg raise angle in nondisabled subjects. Long-term effects of these treatments as well as their ef- fects at different joints and in disabled subjects are unknown. The mechanisms by which myofascial release and contract-relax techniques work and their reported effects deserve further study. Anecdotal claims of benefits of myofascial release to a broad range of pathologies also remain untested. CONCLUSION This study showed that subjects receiving contract-relax treatment increased their range of motion significantly more than those who received leg pull treatment, and the increase in range of motion of subjects in both treatment groups was significantly higher than that of the control group. The results suggest that while both contract-relax and leg pull techniques can significantly increase hip flexion range of motion in normal subjects, contract-relax treatment was more effective and efficient than leg pull treatment. JOSPT REFERENCES Barnes IF: Myofascial Rel~ase Seminar I, p 16. Paoli, PA: Pain and Stress Control Center, 1988 Barnes IF: Therapeutic insight. Phys Ther Forum 4:9, 1987 Barnes IF: Therapeutic insight. Phys Ther Forum 4:4-5, 1987 Barnes IF: Therapeutic Insight. Phys Ther Forum 423-9, 1987 Condon 5, Hutton R: Soleus muscle electromyographic activity and ankle dorsiflexion range of motion during four stretching procedures. Phys Ther 67:24-30, 1987 Etnyre BR, Abraham LD: Antagonist muscle activity during stretching: A paradox reassessed. Med Sci Sports Exerc 20: , 1988 Etnyre BR, Abraham LD: H-reflex changes during static stretching and two variations of PNF techniques. 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