Physical Therapy Korea

The prevalence of forward head posture is increasing owing to changes in the social and working environment where personal computers and smartphones are used for extended periods, as well as because of tasks involving video terminals [1]. According to the Korea Disease Control and Prevention Agency, up to 70% of individuals between the ages of 25 and 42 years exhibit a forward head posture with cervical lordosis of less than 12.5° [2]. Forward head posture is a chronic postural deviation in which the head moves forward from the center line of gravity, resulting in an imbalance of soft tissues around the neck and loss of the normal forward curvature of the cervical spine [3-5]. Forward head posture is diagnosed when the craniovertebral angle (CVA) is less than 50° or when the horizontal distance from the center line of gravity to the tragus is 5 cm or more [6]. The CVA refers to the angle formed between the horizontal line passing through the spinous process of the 7th cervical vertebra and the line connecting the external auditory meatus to the spinous process of the 7th cervical vertebra [7].

A prolonged forward head posture leads to shortening of the neck extensor muscles and elongation of the flexor muscles. This puts strain on joints and muscles, leading to fatigue, pain, and the development of chronic conditions [8]. In the case of forward head posture, the vertical pressure on the neck is approximately 3.6 times higher than that in normal posture. To compensate for this, the tension and muscle activity in the neck increase, and a compensatory action that alters the posture to reduce the load occurs [9,10]. If excessive axial pressure is not effectively counteracted, it can result in microtrauma and neck pain, leading to various negative effects on the neuromusculoskeletal and respiratory systems. These effects include muscle weakness, anatomical deformation of the thoracic cage, impaired respiratory function, and structural changes in spinal curvature [11-14].

In previous studies, various passive and active approaches to posture training have been attempted to treat forward head posture. Kim et al. [15] found that applying sling exercises and stretching resulted in a significant increase in the CVA in the active exercise group compared to that in the group that received simple stretching alone. Jang et al. [16] reported that professional body massage, a passive exercise method that restores spinal alignment, led to a significant increase in the CVA, decrease in pain, and improved symmetry of left- and right-foot pressure, indicating positive outcomes. Lee et al. [17] conducted passive exercises using Kaltenborn’s joint mobilization, active assistive exercises using Mulligan’s joint mobilization, and active exercises involving muscle strengthening to restore proper alignment by improving the CVA in individuals with forward head posture. A comparison after the exercises showed a significant increase in the CVA in the active exercise group compared with that in the passive exercise group. It has been reported that performing therapeutic massage, stretching, active muscle strengthening exercises, and cervical joint mobilization for the splenius capitis and cervicis, sternocleidomastoids, trapezius, levator scapulae, and scalene muscles leads to positive changes in the CVA [18].

However, most previous studies have primarily focused on examining the medium- to long-term effects of intervention techniques, resulting in a lack of studies investigating the immediate effects of a single intervention, and studies on the effects on stress are rare. Stress is a normal physiological response in which the body seeks to maintain homeostasis in the face of external stimuli. However, it has been noted that when the stress response becomes prolonged or repetitive, it can be associated with health issues. Specifically, work-related stress is considered to have a close association with musculoskeletal disorders, such as back pain and neck and shoulder issues [19,20]. Therefore, it was considered valuable to select manual and self-exercise therapy, which have been reported to be effective in previous studies, and apply them to individuals with forward head posture to investigate treatment effects, including stress variables. Thus, the objective of this study was to compare the changes in treatment effects in patients with forward head posture and neck pain after applying self-exercise and manual therapy over a 1-hour period.

1. Participants

In this study, 28 participants with forward head posture accompanied by neck pain were randomly assigned to either a group receiving self-exercise therapy or a group receiving manual therapy, with 14 participants each. Matched allocation was used based on sex. This study was designed as a comparative study. The selection criteria consisted of those with a CVA less than 50° accompanied by a numerical rating scale (NRS) score of 3–4 for neck pain [21]. The exclusion criteria were scoliosis, cervical disc herniation, osteoarthritis, fracture, epilepsy, cardiopulmonary disease, cancer, stroke, and delusion. Patients who could not suitably perform the exercise program of this study owing to conditions such as dementia were also excluded. After sufficiently explaining the research to the 28 participants who met the above recruitment criteria and answering their questions, the Yonsei University Mirae Campus Institutional Review Board approved the study (IRB no. 1041849-202306-BM-098-03). After signing the consent form, the participants were allowed to participate in the training.

2. Outcome Measures

This study measured the CVA, stress level, pain level, and left-right sternocleidomastoid (SCM) stiffness four times: 1) before the intervention, 2) immediately after the intervention, 3) 30 minutes later, and 4) 1 hour later. All subjects wore T-shirts and training suits that did not interfere with the exercise program and evaluation during participation in the training.

In this study, we fixed a digital camera 1 m away and took a picture of the left side posture using the ImageJ software program (ImageJ, National Institutes of Health) to calculate the CVA by measuring the angle formed by the horizontal line passing through the height of the 7th cervical vertebra and the straight line connecting the midpoint of the tragus and the spinous process of the 7th cervical vertebra [7]. The participants were asked to place both arms next to their trunk, look straight ahead, and stand in their usual posture before the measurement (Figure 1).

Figure 1. Craniovertebral angle measurement.

The stress NRS, an effective evaluation tool for measuring current or momentary stress levels in adults and adolescents, was measured by self-diagnosis using a 10-point scale from 0 to 10, where 0 meant no stress and 10 meant maximum stress [22].

The pain scale was measured by self-diagnosis using the pain NRS, which is commonly used, with a 10-point scale from 0 to 10, where 0 indicates no pain and 10 indicates maximum pain [23].

The stiffness of the left and right SCM was measured using MyotonPRO (MyotonAS). The left and right SCM muscles, which are biomechanically related to forward head posture, were measured. Muscle stiffness is a measure of the mechanical properties of tissues along the vertical axis. This is determined by assessing the resistance of the tissues during passive stretching. In this study, the muscle stiffness of the SCM was measured in the neutral position of the neck. The stiffness (S) of a muscle unit was calculated using the formula S = a^max·m^probe/Δl, where a^max represents the maximum amplitude observed in the acceleration signal, m^probe is the mass of the probe (preloaded at 0.18 N), and l represents the amplitude of the displacement signal [24].

3. Experimental Procedure

All subjects were evaluated for CVA, stress level, pain level, and left-right SCM stiffness before the intervention. The subjects were randomly divided into two groups: 1) received manual therapy, 2) underwent self-exercise therapy. The intervention program was conducted accordingly. In the referenced previous studies for designing the exercise program, interventions ranged from short durations of 1 session lasting 3 minutes to longer durations of 1 session lasting 60 minutes, with an average duration of 30 minutes being the most common [15-18]. After conducting a preliminary experiment with the exercise program used in this study, it was found that it took approximately 30 minutes. Therefore, the duration for one session of the exercise program was set at 30 minutes. Subsequently, all subjects were re-evaluated immediately after the intervention, 30 minutes later, and 1 hour later, using the same intervention evaluation as before.

Manual therapy intervention involves joint mobilization, myofascial release, massage, and stretching and is guided by a therapist. The goal of this intervention was to achieve specific outcomes, including increasing lordosis (the natural curve) of the neck, decreasing kyphosis (the excessive curve) of the upper back, and elongating the tense and shortened muscles (Figure 2).

Figure 2. Manual therapy intervention (30 minutes).

The purpose was to achieve normal alignment of the neck by increasing upper cervical flexion and lower cervical extension and decreasing thoracic kyphosis. In the prone position, trapezius and rhomboids pressure massage; levator scapulae, splenius capitis and cervicis, and suboccipital muscle relaxation massage; shoulder joint range of motion passive exercise; and neck-back joint mobilization were performed (10 minutes).

Relaxation massage of the SCM, anterior-middle scalene muscles, pectoralis major, and pectoralis minor; passive stretching; head-neck traction; and neck-back joint mobilization were performed (10 minutes) for the same purpose.

Relaxation massage of the SCM, anterior-middle scalene muscles, levator scapulae, pectoralis major and upper trapezius; passive stretching; and cervical spine joint mobilization were performed (10 minutes) for the same purpose.

Self-exercise therapy is a technique that uses the active muscle contraction of the subject guided by a therapist to increase lordosis of the neck, decrease kyphosis of the upper back, stretch the shortened muscles, and contract the lengthened muscles to restore ideal alignment of the spine (Figure 3).

Figure 3. Self-exercise therapy intervention (30 minutes).

The purpose was to achieve normal alignment of the neck by increasing upper cervical flexion and lower cervical extension and decreasing thoracic kyphosis. In the prone position, the pelvis and lower limbs were positioned on the floor, and upper limb and spinal extension exercises were performed while simultaneously performing cervical retraction exercises to induce concentric contraction of the erector spinae, upper trapezius, rhomboids, and splenius capitis and cervicis (lower part) and eccentric contraction of the suboccipital muscles, SCM, anterior scalene muscles, and splenius capitis and cervicis (upper part). This movement was repeated by changing the quadrupedal position (10 minutes).

For the same purpose, a foam roller was placed on top of the spine from the back to the neck and the patient exercised in the supine position. Thoracic extension and cervical retraction exercises were performed to induce concentric contraction of the erector spinae, trapezius, rhomboids, and splenius capitis and cervicis (lower part) and eccentric contraction of the suboccipital muscles, SCM, anterior scalene muscles, and splenius capitis and cervicis (upper part). Simultaneously, shoulder joint horizontal abduction, external rotation, flexion-extension, scapular posterior tilt, and the pectoralis major and minor muscles were actively stretched (10 minutes).

For the same purpose, active stretching was performed for the SCM, anterior-middle scalene muscles, levator scapulae, and upper trapezius by fixing the opposite upper limb under the hip. Thoracic extension and cervical retraction exercises were performed to induce concentric contractions of the erector spinae, trapezius, rhomboids, and splenius capitis and cervicis (lower part) and eccentric contractions of the suboccipital muscles, SCM, anterior scalene muscles, and splenius capitis and cervicis (upper part) (10 minutes).

4. Data Analysis

The collected data were analyzed using IBM SPSS ver. 25.0 (IBM Co.). The mean and standard deviation were calculated for all the measured variables. An independent t-test was conducted to test for homogeneity between the manual and self-exercise therapy groups. Group × time two-way mixed analysis of variance (ANOVA) was used to assess the interaction effect between groups (manual therapy vs. self-exercise therapy group) and within-group effects (pre-test, post-test, 30 minutes after, and 1 hour after) at a significance level of p < 0.05. The Bonferroni post hoc test (one-way repeated ANOVA test) was used to examine the simple effects over time within each group. The significance level for the post hoc test was set at α = 0.0083.

Table 1 presents the pre-assessment values for sex, age, height, weight, body mass index, CVA, stress level, pain level, and SCM stiffness of the participants. The chi-squared test was conducted for sex, a non-continuous variable, while the independent t-test was used for continuous variables to examine homogeneity between the two groups. The results revealed no significant differences between the groups (p > 0.05) (Table 1).

Table 1 . Pre-intervention between-group comparisons (N = 28).

Variable	MT group (n = 14)	SE group (n = 14)	p-value
Sex (male/female)	8/6	9/5	0.699a
Age (y)	28.43 ± 6.11	26.64 ± 6.07	0.445b
Height (cm)	167.79 ± 6.31	169.79 ± 5.71	0.388
Weight (kg)	65.36 ± 12.02	68.29 ± 13.15	0.544
BMI (kg/m2)	23.12 ± 3.44	23.58 ± 3.81	0.742
CVA (°)	47.00 ± 2.04	45.71 ± 2.61	0.159
Stress	6.07 ± 1.33	5.36 ± 2.10	0.293
Pain	3.57 ± 0.51	3.64 ± 0.50	0.712
Left SCM stiffness (N/m)	191.00 ± 10.18	190.21 ± 12.37	0.856
Right SCM stiffness (N/m)	203.50 ± 15.57	194.79 ± 12.83	0.119

Values are presented as number only or mean ± standard deviation. MT, manual therapy; SE, self-exercise therapy; BMI, body mass index; CVA, craniovertebral angle; SCM, sternocleidomastoid. achi-squared test, bindependent t-test..

The two-way mixed ANOVA revealed that there was no interaction effect between the groups and time for all measurement variables, and no main effects between the groups were observed (p > 0.05). However, a significant effect of time was observed (p < 0.05) (Table 2). Post-hoc analysis using the Bonferroni test revealed that in the manual therapy group, there was a significant increase in the CVA immediately after the intervention compared with those before the intervention, and pain and stress levels were significantly decreased. These effects were maintained for up to 1 hour after treatment (p < 0.0083). In the self-exercise therapy group, the CVA and pain significantly improved immediately after the intervention compared to that before the intervention, and these treatment effects were maintained until 1 hour after the treatment (p < 0.0083). The stress level significantly decreased immediately after the intervention compared with that before the intervention and was maintained after 30 minutes (p < 0.0083), but increased after 1 hour to a level that was not significantly different from that before the intervention. Left SCM stiffness significantly decreased immediately after the intervention (p < 0.0083), but increased after 30 minutes, showing no statistically significant difference from the pre-intervention value. There was no significant decrease in right SCM stiffness after the intervention (Figure 4).

Table 2 . Comparison of variables pre- and post-test (N = 28).

Variable	MT group (n = 14)					SE group (n = 14)				Effect	p-value
	Pre-test	Post-test	After 30 min	After 1 h		Pre-test	Post-test	After 30 min	After 1 h
CVA (°)	47.00 ± 2.04	58.64 ± 3.56	55.93 ± 3.22	55.79 ± 3.17		45.71 ± 2.61	57.50 ± 3.18	54.43 ± 3.84	54.21 ± 3.85	Time	< 0.001*
										Group	0.201
										Time × Group	0.974
Stress	6.07 ± 1.33	3.14 ± 1.70	3.29 ± 1.64	3.71 ± 1.44		5.36 ± 2.10	2.43 ± 1.99	2.64 ± 1.82	3.36 ± 1.45	Time	< 0.001*
										Group	0.325
										Time × Group	0.433
Pain	3.57 ± 0.51	1.07 ± 0.83	1.36 ± 0.84	1.50 ± 0.65		3.64 ± 0.50	1.21 ± 0.89	1.57 ± 0.51	1.79 ± 0.43	Time	0.004*
										Group	0.324
										Time × Group	0.898
Left SCM stiffness (N/m)	191.00 ± 10.18	177.36 ± 11.72	182.29 ± 12.74	183.50 ± 11.95		190.21 ± 12.37	175.36 ± 8.13	180.00 ± 9.00	181.29 ± 8.59	Time	< 0.001*
										Group	0.642
										Time × Group	0.860
Right SCM stiffness (N/m)	203.50 ± 15.57	189.00 ± 13.54	194.57 ± 15.94	195.64 ± 15.23		194.79 ± 12.83	181.21 ± 10.76	185.14 ± 12.11	186.36 ± 11.50	Time	< 0.001*
										Group	0.090
										Time × Group	0.792

Two-way mixed ANOVA test. Values are presented as mean ± standard deviation. ANOVA, analysis of variance; MT, manual therapy; SE, self-exercise therapy; CVA, craniovertebral angle; SCM, sternocleidomastoid. *p < 0.05..

Figure 4. Results of variables, one-way repeated ANOVA test. ANOVA, analysis of variance; CVA, craniovertebral angle; SCM, sternocleidomastoid; R., right; L., left. **p < 0.0083.

This study aimed to compare the effects of manual and self-exercise therapy in relation to forward head posture to determine the effects of interventions on changes in the CVA, stress level, pain level, and left-right SCM stiffness. Initially, 28 participants were randomly divided into two groups-one for each intervention. The effects of the interventions were measured repeatedly after 30 minutes and 1 hour and evaluated by comparing the post-intervention measurements with the pre-intervention measurements within and between groups.

Our results revealed that post the implementation of manual therapy and self-exercise, both groups experienced a significant increase in the CVA compared to that before intervention. According to Lee et al. [17], a decrease in the CVA is associated with a more severe forward head posture. The improved angle was sustained for up to 1 hour after therapy. Like the findings of Katavich [25]’s study, manual therapy not only promotes relaxation of soft tissues and muscles and increases the range of motion, but also suppresses voluntary and involuntary muscle activity and pain through neurophysiological stimulation. These effects are believed to contribute to the improvement in movement and reduction in pain, leading to an increase in the CVA [25]. Regarding the effect of self-exercise, Sheikhhoseini et al. [6] previously demonstrated that motor control through active muscle contraction resulted in improved performance and subsequently increased CVA. Similarly, Lee et al. [17] found that active intervention was more effective than passive intervention. In contrast, Katavich [25] showed that spinal manipulation therapy, a passive technique, had a greater short-term effect than other treatment techniques. However, the results of the present study did not show any significant differences between the two groups. This could be attributed to the fact that the study assessed the immediate effects following a 30-minute intervention session, during which various manual therapy techniques, including massage and stretching, were applied.

We found that both self-exercise and manual therapy were effective in stress relief. With respect to manual therapy, our finding is consistent with those of previous studies. Youn et al. [26] demonstrated that stretching and massage have a positive impact on stress reduction. Kim et al. [27] also reported that implementing neck massages in a group of middle-aged females effectively relieved stress.

In addition, there are studies that support our findings that self-exercises are also effective in stress reduction. Light et al. [28] suggested that self-exercise alleviates stress and positively impacts physiological responses to stress, promoting rapid recovery. Additionally, Seo [29] reported that self-exercise in middle-aged females with obesity resulted in stress relief. However, in our study, the treatment effect of manual therapy was found to be maintained for a longer period than self-exercise in providing sustained stress relief.

Furthermore, the pain level was significantly reduced up to 1 hour after the intervention compared with that before the intervention when self-exercise and manual therapy were applied. Lluch et al. [21] compared the effects of the craniocervical flexion exercise intervention and the upper cervical spine mobilization intervention in people with chronic neck pain with NRS scores of 3 or more. They found that both groups showed a decrease in pain immediately after the intervention. However, unlike our finding, the active exercise group showed a larger decrease. Compared to the study by Lluch et al. [21], the manual therapy intervention applied in our study was equally effective compared to the self-exercise because it applied a mixture of myofascial release, massage, and stretching in various postures as well as simple cervical mobilization.

However, both treatments in our study were not very effective in reducing SCM stiffness. It reduced immediately after treatment only in the left SCM of the self-exercise group, but could not be maintained even 30 minutes after treatment. Kocur et al. [30] argued that the increased stiffness of the trapezius, SCM, and splenius capitis muscles is not a single characteristic of forward head posture, but rather a secondary symptom that appears in conjunction with neck pain and other disorders. Therefore, even in case of a forward head posture, it should not be assumed that the SCM stiffness is high. Furthermore, one possible explanation for these results is that the SCM is a muscle that does not require significant activation in the supine position. If the SCM stiffness was measured in a posture where the weight of the head must overcome against gravity, such as in a sitting or standing posture, different results may have been obtained. In addition, it is thought that it is necessary to measure muscle fatigue more objectively using electromyography frequency analysis rather than measuring muscle stiffness.

The limitations of this study include the insufficient number of study participants and the fact that only the ultra-short-term effects of one-time application were compared. Therefore, future studies are required to compare the mid- to long-term effects of self-exercise or manual therapy for turtleneck patients.

This study investigated the effects of self-exercise and manual therapy in patients with forward head posture and neck pain with an NRS score of 3–4. Both groups showed an increase in the CVA and a decrease in stress and pain after the intervention, which lasted 30 minutes. No significant differences were observed between the groups. This study has clinical significance in that it provides evidence that both self-exercise and manual therapy can have a positive effect on the treatment of forward head posture, even with a short intervention of 30 minutes per session.

None.

None to declare.

No potential conflicts of interest relevant to this article are reported.

Conceptualization: GS, DK, HJ. Data curation: GS, DK, HJ. Formal analysis: GS, DK, HJ. Investigation: GS, DK, HJ. Methodology: GS, DK, HJ. Project administration: GS, HJ. Resources: GS, HJ. Software: GS, DK, HJ. Supervision: GS, HJ. Validation: GS, HJ. Visualization: GS, DK, HJ. Writing - original draft: GS, HJ. Writing - review & editing: GS, HJ.