Effects of the active release technique on pain and range of motion of patients with chronic neck pain (2024)

Abstract

[Purpose] To compare the influences of the active release technique (ART) and jointmobilization (JM) on the visual analog scale (VAS) pain score, pressure pain threshold(PPT), and neck range of motion (ROM) of patients with chronic neck pain. [Subjects]Twenty-four individuals with chronic neck pain were randomly and equally assigned to 3groups: an ART group, a joint mobilization (JM) group, and a control group. Before andafter the intervention, the degree of pain, PPT, and ROM of the neck were measured using aVAS, algometer, and goniometer, respectively. [Results] The ART group and JM groupdemonstrated significant changes in VAS and ROM between pre and post-intervention, whileno significant change was observed in the control group. Significant differences in thePPT of all muscles were found in the ART group, while significant differences in allmuscles other than the trapezius were found in the JM group. No significant difference inPPT was observed in any muscle of the control group. The posthoc test indicated nostatistically significant difference between the ART and JM group, but the differences ofvariation in VAS, PPT, and ROM were greater in the ART group than in the JM and controlgroups. [Conclusion] ART for the treatment of chronic neck pain may be beneficial for neckpain and movement.

INTRODUCTION

People have a 70% likelihood of developing neck pain during their lives; thus, neck pain isan important issue affecting economic productivity in modern society1⁾. Neck pain is a work-related musculoskeletal disorder thatcan occur when a person works for a long time or at a high intensity. An increasing numberof patients also visit hospitals complaining of pain occurring not only in the neck but alsoin the upper extremities and head as a result of sustained excessive tension2⁾. Although the issue of neck pain is becomingincreasingly common and important, research into optimal treatmentslacking3⁾.

A common cause of neck pain is mechanical dysfunction, which causes abnormal jointmovement, as abnormal cervical joint mobility inside the joint capsule can limit neckmovement4^, 5⁾. Additionally, unbalanced soft tissue around the head and neckstructure can place limits on the range of motion (ROM) of the head and cause neck pain6⁾. Therefore, many treatments are performedwith the aim of restoring soft tissue function or mobility to the joints in patients withchronic neck pain. Joint mobilization (JM) and joint manipulation are the most widely usedmethods to increase mobility inside the joint capsule. These methods have been reported toincrease the ROM and relieve pain7^, 8⁾. However, JM and joint manipulationperformed at the end range of the ROM directly on the joints of the cervical vertebrae cancause tension in the patient’s neck muscles, because the cervical vertebrae are the mostsensitive part of the spine and this tension protects the nerves and blood vessels9⁾.

The active release technique (ART) is a manual therapy for the recovery of soft tissuefunction that involves the removal of scar tissue, which can cause pain, stiffness, muscleweakness, and abnormal sensations including mechanical dysfunction in the muscles,myofascia, and soft tissue10⁾. Theeffectiveness of ART has been reported for carpal tunnel syndrome, Achilles tendonitis, andtennis elbow, all of which involve soft tissue near joints in the distal parts of thebody11⁾. ART is also effective atreducing pain and increasing ROM in patients with a partial tear of the supraspinatustendon12⁾. Most patients with chronicneck pain experience pain and movement limitation as a result of soft tissue impairment inthe neck13⁾. Accordingly, more research onART for the treatment of the soft tissues of the neck is warranted. However, no previousstudies have assessed how ART can improve ROM in patients with neck pain.

Therefore, the purpose of this study was to compare the influence of ART and JM on thevisual analog scale (VAS) score, pressure pain threshold (PPT), and neck ROM of patientswith chronic neck pain, with the aim of elucidating additional information on their effectsand identifying more efficient treatments that can be used in clinical settings.

SUBJECTS AND METHODS

The study subjects were 24 patients admitted to Hospital A in Gangnamgu who had a 3-monthor longer history of neck pain and had mild disability based on the Neck Disability Index(NDI; 5–14 points). The sample size of this study was based on that of Hyun14⁾, while considering the subject dropoutrate, and accounting for significance level (5%), power of the test (0.8), and the effectsize (f=0.7). Patients with structural abnormalities involving bone fracture or nerves thosewho had undergone surgery for hernia or had high blood pressure, spondyloarthritis, lumbarspinal stenosis, or scoliosis were excluded from the study. The participating patientsunderstood the study purpose and associated information and provided their written consentto participation. This study was conducted using a procedure ethically suitable for humanresearch in accordance with the Declaration of Helsinki.

We used the VAS to evaluate the degree of neck pain. The VAS is a subjective scoring methodfor recording the degree of present pain from 0 (no pain) to 10 (the most severe pain everexperienced) on a 10-cm scale. The VAS is difficult to compare among patients because of thesubjective nature of the pain, but its reproducibility has been recognized in individualpatients (ICC=0.97)15⁾.

The PPT measurement was performed by one investigator using an algometer. The right andleft upper trapezius and sternocleidomastoideus (SCM) were pressed at a constant speed. Thesubject was asked to respond immediately when the pressure changed to pain, and themechanical pressure was recorded. The mean value of two measurements was used; increasingPPT values indicate a higher-pressure pain threshold. An algometer is particularly usefulfor measuring the trigger point in myofacial pain syndrome, because it can determine theprecise location of the source pain and quantify the pressure sensitivity of muscles(ICC=0.78–0.93)16^, 17⁾.

Passive ROM was measured by fixing the subject’s shoulder so that it was not affected bythe other parts of the trunk. Then, neck flexion, extension, right side bending, left sidebending, right rotation, and left rotation were measured. The range of the angle wasmeasured with a therapist passively assessing the patient’s pain-free neck-joint ROM18⁾.

The 24 subjects with chronic neck pain included in the study were randomly assigned to oneof three groups following an equivalent control group pre-test/post-test design. For 3weeks, the ART and JM groups received treatment twice per week for 20 minutes. After all theinterventions were completed, the VAS score, PPT, and ROM were measured again. In the ARTgroup, ART was used to treat the muscles demonstrating scar tissue, among the musclesinvolved in neck movement. After shortening based on fiber texture in the longitudinaldirection, soft tissue mobilization was performed with active or passive stretching tolengthen the tissue that had been shortened12⁾.

JM was performed using Kaltenborn’s techniques of traction and gliding. In order to relievepain with physiological movements including flexion, extension, side bending, and rotation,traction at Grade I or II was performed for 10 seconds. Additionally, in order to recoverhypomobility, traction and gliding were performed at level 3 and maintained for 7 seconds.Both treatments included 2–3 seconds of rest and were repeated 10 times19⁾. Subjects in the control group did not receive anytreatment for chronic neck pain.

SPSS 18.0 for Windows was used to analyze the results. In order to confirm the homogeneityof subjects’ general characteristics and dependent variables, descriptive statistics and theKruskal-Wallis test were used. The Wilcoxon rank test was performed to assess the differencebetween pre- and post-treatment values in each group, and the Mann-Whitney U test was usedto identify significant differences among the groups. The threshold for statisticalsignificance was chosen as 0.05.

RESULTS

The extent of change in VAS score, PPT, and ROM was compared between patients with chronicneck pain who underwent ART or JM. Twenty-four patients with a 3-month or longer history ofchronic neck pain participated in this study. The three groups demonstrated no significantdifferences in NDI scores, ages, heights, or weights (p>0.05) (Table 1).

The ART and JM groups both demonstrated significant improvements in VAS pain scores(p<0.05), but no significant change was observed in the control group (p>0.05). ThePPT significantly increased (p<0.05), in every muscle measured in the ART group, and inall muscles other than the right upper trapezius in the JM group. Muscle PPT demonstrated nosignificant change in the control group (p>0.05) (Table 2).

After treatment, the ART and JM groups both demonstrated significant increases (p<0.05)in every neck joint ROM parameter, while no significant changes were observed in the controlgroup (p>0.05) (Table 2).

The extent of change in the VAS pain score and PPT between pre- and post-treatmentsignificantly differed across the three groups (p<0.05). The posthoc test indicated thatchanges in the VAS scores significantly differed between the ART and control groups, andbetween the JM and control groups (p<0.05), but not between the ART and JM groups(p>0.05). The changes in PPTs of the right upper trapezius and left SCM significantlydiffered to between the ART and JM groups (p<0.05); however no significant differenceswere observed in the other muscles (p>0.05). Between the JM and control groups, thechange in right SCM PPT demonstrated a significant difference (p<0.05); however, nodifference was observed in other muscles (p>0.05). Between the ART and control group, thechange in PPT significantly differed for all the measured muscles (p<0.05). The changesin VAS score and PPT were greater in the ART group than in the JM group, but thesedifferences were not statistically significant (Table3).

The extent of change in ROM after the treatments significantly differed across the threegroups (p<0.05). The posthoc test indicated that the change in ROM significantly differedbetween the ART and JM groups only in neck flexion (p<0.05), but not in other ROMmeasurements (p>0.05). There was no significant difference in neck flexion ROM betweenthe JM and control groups (p>0.05), but all other ROM parameters significantly differedbetween these groups (p<0.05). The ART and control groups significantly differed in termsof the change in ROM for all the parameters measured (p<0.05). The change in ROM wasgreater in the ART group than in the JM group, but this difference was not reachstatistically significant (Table 3).

DISCUSSION

Repetitive motions and the use of smart phones and tablets in abnormal head postures canstress the head, neck, and shoulder areas. Additionally, abnormal head posture can causemechanical dysfunction of the cervical joint, which can lead to pain, fibrosis of softtissue, adaptive shortening, loss of flexibility, and mechanical deformation reflecting thecondition of hypomobility, where there is no movement inside the normal joint capsule20^, 21⁾. When mechanical dysfunction is present in a vertebra, manual therapyis typically performed, and it can be an effective method of relieving neck pain related tosuch dysfunction22⁾. JM is used to treatjoints with hypomobility or progressive limitation of mobility, by identifying a cervicalsegment with abnormal mobility and irritating the sensory receptors that sense pain, thuseliciting effects on the muscle, which in turn stimulate the muscles to apply force in theappropriate direction8⁾.

After 3 weeks of JM, the VAS, ROM, and PPT values of muscles other than the right uppertrapezius demonstrated significant improvements compared to their pre-test values. The PPTalso increased in the right upper trapezius, but the difference was not statisticallysignificant. The trapezius is particularly susceptible to damage by repetitive movements ofthe hand and arm while performing work such as using a computer23⁾. Most of the study participants were right-handed and thusperformed more movement of the right upper extremity than the left, which may explain whythe improvement of the right upper trapezius PPT was not reach statisticallysignificant.

ART is a method for treating the soft tissues such as the tendon, nerve, and myofascia, andis performed for repetitive strain injury, acute injury, and functional fixation damage dueto abnormal posture maintained over the long term. Furthermore, ART is an effective atresolving adhesion of scar tissue and the soft tissue that causes pain, spasm, muscleweakness, tingling, and other symptoms11⁾.

Robb et al.24⁾ demonstrated immediateimprovement of muscle PPT when ART was used to treat patients with adductor strain.Additionally, in a study by Tak et al.10⁾,ART treatment for 3 weeks on the gluteus medius of a patient with low back pain for 3 weeksresulted in improvement of the patient’s VAS score and PPT. Although our target areadiffered from the studies of Tak et al.10⁾and Robb et al.24⁾, significantimprovement was observed in the VAS score, PPT, and ROM after using ART to treat the neckmuscles in the present study. It is our opinion that these improvements in VAS score and PPTafter treatment is the result of decreases in muscle tone after removing scar tissueadherent to soft tissue.

In a study by James25⁾ involving 20 youngmen with no injury of the lower extremity, hamstring flexibility increased immediately afterART was applied. Similarly, in the present study, ROM significantly increased after ART wasapplied on the neck for 3 weeks. This finding indicates that scar tissue, which can limitthe mobility of soft tissue, can be removed by ART and thus relieve limitations ofmovement12⁾.

Although no statistically significant difference was detected in many cases, the change inthe VAS score, PPT, and ROM demonstrated a consistent trend toward being greater in the ARTgroup than in the JM group. This greater effect may be related to the observation that softtissue injury is the cause of pain in 87.5% of neck pain cases, and ART is performeddirectly on the injured soft tissue13⁾,whereas JM treats the limited area of the joint. This study compared the effect of treatmentover a short period of 3 weeks, and thus, it remains unclear how long its effectiveness ismaintained. Longerterm follow-up surveys are needed after the cessation of treatment.Additionally, it is difficult to generalize our findings, as the sample sizes were small. Inorder to reinforce these findings, more research is needed.

In conclusion, this study compared the VAS score, PPT, and ROM across 24 subjects withchronic neck pain receiving ART, JM, or no treatment. It revealed that ART and JM bothpositively affected the VAS score, PPT, and ROM, and that the two methods demonstrated fewsignificant differences in their effects. Thus, ART and JM are both effective for thetreatment of patients with chronic neck pain, but ART demonstrated a trend toward greatereffectiveness for patients with neck pain involving soft tissue injury. Therefore, ARTappears to be a better option for treating patients with chronic neck pain in the clinicalsetting. Follow-up research involving greater numbers and diversity of subjects with longerterms are needed to expand upon these findings.

REFERENCES