search for




 

Effect of Breathing Technique-Based Exercises on Alignment and Mechanical Properties of Muscles Related to Upper Cross Syndrome
J Korean Soc Phys Med 2024;19(4):21-33
Published online November 30, 2024;  https://doi.org/10.13066/kspm.2024.19.4.21
© 2024 Journal of The Korean Society of Physical Medicine.

Dong-Jin KooㆍSi-Chan Park, PT1ㆍJae-Yoon ParkㆍJi-Woo Jung, PT1ㆍHyeok-Gyu Kwon, PT, PhD†

Department of Physical Therapy, College of Health Science, Eulji University
1Department of Physical Therapy, Graduate School, Eulji University
†Hyeok-Gyu Kwon
khg0715@hanmail.net, https://orcid.org/0000-0002-6654-302X
Received August 21, 2024; Revised September 5, 2024; Accepted October 23, 2024.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
PURPOSE: Many studies have reported the effects of various exercises on upper crossed syndrome (UCS), but no study has reported the effects of exercise according to the breathing method. This study examined the most effective breathing methods (abdominal, thoracoabdominal, and thoracic breathing) when applied to exercise in UCS.
METHODS: Forty-two adults with UCS were divided randomly into three breathing groups: 1) abdominal, 2) thoracoabdominal, and 3) thoracic. Each group was trained in their respective breathing methods and underwent interventions, including deep cervical flexor strengthening, minor pectoral stretching, modified prone cobra, and wall slide exercises. The exercise sessions were conducted twice a week for four weeks, each lasting 15–20 minutes. The neck disability index, visual analog scale, distance from the ground to the acromion, craniovertebral angle (CVA), cranial rotation angle (CRA), and muscle elasticity were measured.
RESULTS: Significant differences were observed in the CVA and CRA between the abdominal and thoracic breathing groups. The abdominal breathing group showed significant improvements in tension and stiffness of the sternocleidomastoid muscle. Overall, the abdominal, thoracoabdominal, and thoracic breathing groups showed improvements in their forward head posture in that order of effectiveness.
CONCLUSION: All groups showed significant improvements in UCS. These findings suggest that exercises incorporating abdominal breathing are particularly effective and can be recommended for patients with UCS.
Keywords : Breathing, Exercise program, Posture control, Upper crossed syndrome
Ⅰ. Introduction

With the expansion of media, postural problems are increasing rapidly in modern society. In particular, as computers and smartphones have become widespread, there is a tendency for people to protrude their heads forward from the spinal axis. Postural problems, such as forward head posture (FHP) and rounded shoulder posture (RSP), will result if this position is maintained for a long time [1]. FHP, known as ‘Turtle Neck Syndrome,’ refers to a postural change in which the head moves forward, which can cause fatigue and neck pain by putting pressure on joints and muscles [2]. In addition, FHP causes the weakening of the middle trapezius, lower trapezius, longus capitis, and longus colli, along with excessive muscle tension, such as upper trapezius, shoulder scapula, sternocleidomastoid, and suboccipitalis [3].

RSP refers to a posture in which forward protrusion of the acromion of the shoulder joint around the line of gravity, along with elevation, protraction, and downward rotation of the scapular, causes the body to lean forward. This posture can lead to an imbalance in shoulder muscles, accompanied by weakening of the lower trapezius and serratus anterior muscles and shortening of the pectoralis minor muscle [4]. Abnormal patterns observed in a specific muscle group, including FHP and RSP, are referred to as upper crossed syndrome (UCS), which can lead to tension headaches and pain in surrounding muscles and joints [5]. Furthermore, it can restrict the range of motion of the cervical joints, leading to discomfort in daily life, associated with decreased sleep quality, anxiety, depression, and upper limb dysfunction [6-8]. The diagnosis and evaluation of UCS are crucial for treatment plans. Various methods have been used traditionally to evaluate the muscle status and posture, such as assessing muscle strength, endurance, and flexibility. More precise and accurate measurements have become possible with the development of multidimensional measuring instruments [9].

Regarding the treatment for USC, various therapies, including ultrasound, electrostimulation, and therapeutic exercises, have been mainly used [10]. Pectoralis minor stretching is effective in relieving RSP related to UCS, increasing the range of flexion in the cervical joints. In addition, raising the arm while suppressing upper trapezius activity by reducing the humerus abduction angle in the modified prone cobra exercise is effective in strengthening the lower trapezius [11,12]. A previous study reported that performing deep cervical flexor strengthening exercises and static stretching for subjects with FHP significantly improved posture and reduced pain [13]. Furthermore, significant increases in the activation of the cervical extensor, lower trapezius, and posterior shoulder muscles have been reported [13]. Other studies reported that wall slide exercises activate the serratus anterior and the upper and lower trapezius [14]. These results confirmed that UCS can be improved using various therapeutic exercises.

Recent studies showed that breathing exercises are important in exercise intervention to improve abnormal posture [15-17]. The way of breathing is divided into three types according to the use of muscles: 1) Thoracic breathing is known to be effective in increasing the mobility of the rib cage, contracting breathing muscles, improving cough ability, improving body alignment and breathing ability by expanding the rib cage to inhale sufficiently through the nose and then exhaling slowly through the mouth [18]. 2) Abdominal breathing contracts the diaphragm during inspiration and expands the lungs to expand the abdomen when air flows in. The abdomen contracts when air is released through diaphragm relaxation during exhalation. This breathing method can have efficient exercise effects, such as reducing back pain, restoring function, and relieving muscle tension [19]. 3) Thoracoabdominal breathing is a body breathing method that maintains abdominal pressure by making the most of inspiration and expiration. Thoracoabdominal breathing helps stabilize the body by strengthening the central muscles of the body through repeated slow and strong muscle contractions [20]. This breathing method is effective in correcting posture, improving flexibility and balance, and preventing injury [21]. Previous studies evaluated the postural changes, joint range of motion, pain, and breathing function after intervention through abdominal, thoracic, and thoracoabdominal breathing exercises and reported them to be effective in improving the FHP [15]. The combination of exercise and breathing interventions in patients with low back pain had a positive effect on spinal stabilization and pain reduction [16]. On the other hand, studies on the effects of each breathing method when applying various breathing methods to exercise interventions are still insufficient.

Therefore, this study examined the differential impacts of various breathing methods applied during exercise on subjects with UCS. The study aimed to identify effective breathing methods for exercise interventions to be applied effectively in the treatment of UCS.

Ⅱ. Methods

1. Subjects

The required sample size was calculated using G*power software (version 3.1.9.7, University of Kiel, Kiel, Germany). To evaluate the effectiveness of breathing technique-based exercises on UCS, parameters were set: ANOVA: fixed effects, omnibus, one-way, a significance level of .05, a power of .80, and an effect size of .5. Based on these calculations, 42 subjects with UCS were recruited for this study. Subjects with a history of surgical procedures on the neck or lower back, those with confirmed disc issues in the neck or lower back, and those who exercised excessively before the experiment were excluded. All subjects received a thorough explanation of the purpose and methods of the study and voluntarily expressed their willingness to participate. Table 1 lists the general characteristics of the subjects who participated in this study.

General characteristics of the subjects

Thoracic breathing group
(n = 14)		 Abdominal breathing group
(n = 14)		 Thoracoabdominal breathing group
(n = 14)
Gender(Male/Female) 6/8 8/6 8/6
Age(years) 20.74 ± 1.93α 20.50 ± 2.14 20.42 ± 2.13
Hight(cm) 167.41 ± 7.01 168.93 ± 6.10 170.17 ± 7.30
Weight(kg) 63.56 ± 9.60 63.48 ± 7.48 64.19 ± 12.12

αMean (± standard deviation)

2. Experimental Design

This study examined the effects of a four-week exercise intervention combined with breathing exercises on UCS. Before and after the intervention, changes in the neck disability index (NDI), visual analog scale (VAS), distance from the ground to the acromion (DGA), craniovertebral angle (CVA), cranial rotation angle (CRA), and muscle elasticity were measured and compared.

Before the intervention, general characteristics such as gender, age, height, and weight were collected from all subjects. They were then assigned randomly into three groups: thoracic breathing group, abdominal breathing group, and thoracoabdominal breathing group, with 14 subjects in each group. Appropriate breathing methods and exercise education were provided according to each group. The exercise intervention was conducted twice a week for four weeks. After the intervention, the pre-intervention assessment items were re-evaluated similarly. The results were statistically analyzed to evaluate the effects of the exercise intervention (Fig. 1).

Fig. 1. Study flow chart.

3. Measurement Tools and Methods

1) Neck Disability Index (NDI)

The Korean version of the NDI questionnaire developed by Song Kyung-jin was used to assess the extent of daily life limitations caused by neck pain [22]. This questionnaire consists of 10 items: pain intensity, personal care, lifting, reading, headaches, concentration, work, driving, sleeping, and recreation. Each item was scored from 0 to 5, with higher scores indicating greater limitations in daily activities caused by neck pain. The total NDI score is the sum of the subject item scores, where a higher score indicates a greater limitation: a total score of 0–4 indicates no disability; 5–14 indicates mild disability; 15–24 indicates moderate disability; 25–34 indicates severe disability; 35 or above indicates complete disability [23].

2) Visual Analogue Scale (VAS)

The VAS was used to assess the degree of neck and shoulder pain in the subjects. The VAS is a tool that allows subjects to express their subjective pain levels. The VAS consists of a 10 cm line marked with a scale from 0 to 10, where 0 indicates no pain and 10 indicates unbearable pain [24].

3) Measurement of the Degree of RSP

The RSP was evaluated by placing the subjects in a supine position, and the vertical DGA was measured using markers. A measurement distance of 2.5 cm or less was classified as normal shoulder posture, while a distance greater than 2.5 cm was classified as RSP [25].

4) Measurement of the Degree of FHP

(1) Craniovertebral angle (CVA) and cranial rotation angle (CRA)

The subjects stood upright and moved their necks up and down three times to align before measuring the CVA and CRA. During this time, the subjects kept their arms relaxed by their sides.

For the actual measurements, the researcher placed stickers for location marking on the spinous process of the seventh cervical vertebra (C7), the tragus of the ear, and the outer canthus of the eye. A tripod was positioned approximately one meter from the subject for the measurements. Using the built-in measurement application of a smartphone (iPhone 12 Pro, Apple, USA, 2020), the camera lens was aligned parallel to the ground, and a side view of the subject was captured. If the stickers were not visible on the screen because of the length of the hair, the subject’s hair was tied back or moved to the side for the photograph.

The captured images were analyzed using APECS Pro Plus (APECS: AI Posture Evaluation 8.3.5, Saneftec, France, 2018). The CVA was determined by measuring the angle between the horizontal line passing through the C7 sticker and the line connecting the C7 sticker to the tragus of the ear. Similarly, the CRA was determined by measuring the angle between the line connecting the C7 sticker to the tragus and the line connecting the tragus to the outer canthus of the eye (Fig. 2) [26].

Fig. 2. Craniovertebral Angle (CVA), Cranial Rotation Angle (CRA), and Sagittal Shoulder Posture (SSP).

5) Mechanical properties of muscles

This study used a contact soft tissue measurement device (MyotonPRO, MyotonAS, Estonia, 2016) to measure muscle tone and elasticity. This device is non-invasive and can determine muscle tone through the resonance frequency (F, Hz) and biomechanical properties through the dynamic stiffness (S, N/m) values in a short time [27]. Furthermore, it can measure muscle elasticity (D) through the logarithmic decrease in oscillation.

The MyotonPRO was used to measure the muscle elasticity of the upper trapezius, lower trapezius, levator scapulae, sternocleidomastoid, and pectoralis major muscles, which are related to FHP. The posture of the subjects varied according to the measurement location: the levator scapulae, sternocleidomastoid, and pectoralis major muscles were measured in the supine position, while the upper trapezius and lower trapezius muscles were measured in the prone position. Accurate data were ensured by taking measurements twice on both sides of each target muscle and recording the average F, S, and D values [28]. Various studies using Myoton have reported that it is a reliable tool for measuring the muscle properties, and it has been particularly noted for its high reliability in measuring muscles in young adults [29,30,27,31,32,9].

4. Intervention

The subjects were assigned randomly to one of three breathing methods: thoracic, abdominal, or thoracoabdominal. The intervention was conducted twice weekly for four weeks, with 14 subjects assigned to each breathing method. All subjects underwent standardized exercises and performed these exercises along with their assigned breathing method.

1) Breathing Methods

Before the intervention, the subjects received pre-education on breathing methods. After confirming that each subject could perform the thoracic breathing, abdominal breathing, and thoracoabdominal breathing methods correctly, they were instructed to begin the assigned breathing method. During performing the exercise, exhalation and inhalation were repeated according to the therapist's verbal guidance.

(1) Thoracic Breathing

For the chest breathing method, the subjects were guided to inhale through the nose, expanding the ribs outward. They were then instructed to exhale through the mouth, contracting the ribs [33].

(2) Abdominal Breathing

For the abdominal breathing method, the subjects were guided to inhale through the nose, expanding the abdomen forward. During exhalation, the subjects were instructed to draw the abdomen inward, paying attention not to raise the shoulders excessively [34].

(3) Thoracoabdominal Breathing

For the thoracoabdominal breathing method, subjects were guided to inhale through the nose, expanding the lower ribs and abdomen forward and sideways. During exhalation, they were instructed to draw the abdomen inward and contract the lower ribs [35].

2) Exercise intervention to improve UCS, In this study, the target muscles were the upper trapezius, lower trapezius, levator scapulae, sternocleidomastoid, and pectoralis major, which are related to RSP and FHP. Four exercise interventions were applied to activate these muscles optimally, with each subject spending 15–20 minutes on the exercises. All subjects were instructed to keep their gaze forward during the exercises.

(1) Pectoralis Minor Stretching

The subjects started by standing and facing forward, with their arms fixed against a wall at a 120° shoulder angle. They were then guided to push their torso forward to abduct the scapulae horizontally while maintaining a stable spinal posture. The stretch was performed for 30 seconds, three sets on each side alternately [36,11]

(2) Modified prone cobra

The subjects positioned themselves prone with their arms placed alongside their bodies, externally rotating their arms so that their thumbs pointed towards the ceiling. They then performed a movement to lift their torso. This exercise was carried out by holding the position for 10 seconds, followed by a three-second rest, repeated three times for three sets. A 30-second rest period was applied between each set [12].

(3) Wall slide

The subjects stood upright, facing a wall with their feet shoulder-width apart, positioning their shoulders and elbows at a 90° angle. The edge of the ulna on the forearm was placed against the wall, and the forearm was then pushed upward along the wall. The subjects maintained a straight torso during the exercise to minimize compensatory movements. They slowly returned to the starting position at the end range of shoulder flexion. This movement was repeated 10 times for three sets, with a 30-second rest period between each set [37].

(4) Deep cervical flexor strengthening exercises

The subjects, in the supine position, performed an exercise where they extended their necks backward, gradually increasing the duration to hold and relax for four, six, and eight seconds. Each set consisted of 10 repetitions with a three-second rest between each repetition, and three sets were performed [38]. A 30-second rest period was applied between each set to prevent fatigue and injury to the neck extensor muscles due to the over-application of holding and relaxing exercises.

5. Statistical Analysis

The statistical data for this study were analyzed using IBM SPSS Statistics 29.0 (IBM Statistical Package for the Social Sciences, IBM, USA). A paired t-test was conducted to compare the pre- and post-intervention results within each group. The differences in pre- and post-intervention values among the three groups were verified by performing a one-way ANOVA (Analysis of Variance), followed by post-hoc testing using the LSD (least square difference) method. The statistical significance level was p < .05.

Ⅲ. Results

1. NDI

A comparison of the pre- and post-intervention in the thoracic breathing group and the abdominal breathing group revealed a significant decrease in the values after the intervention (p < .05). On the other hand, the pre- and post-intervention results were similar in the thoracoabdominal breathing group. No significant difference was observed among the three groups (p > .05) (Table 2).

Comparison of NDI, VAS, DGA, CVA, and CRA before and after the intervention within and between groups

Thoracic breathing group Abdominal breathing group Thoracoabdominal breathing group
Pre Post Pre Post Pre Post
NDI 3.78 ± 2.11α 2.50 ± 2.37† 4.78 ± 2.45 2.85 ± 2.07† 3.78 ± 3.84 3.07 ± 3.56
VAS 2.85 ± 1.79 2.78 ± 2.12 2.23 ± 1.94 1.85 ± 1.47 2.64 ± 1.92 2.57 ± 1.88
DGA (cm) 4.42 ± 1.28 3.12 ± 1.29† 4.44 ± 1.25 3.44 ± .99† 4.24 ± .78 3.20 ± .94†
CVA (˚) 57.21 ± 5.05 57.78 ± 5.26 56.00 ± 4.77 59.50 ± 5.21*,† 56.78 ± 5.38 60.21 ± 4.22*,†
CRA (˚) 154.92 ± 3.87 155.07 ± 3.26 159.21 ± 5.19 154.35 ± 4.32*,† 160.71 ± 8.25 156.00 ± 6.44*,†

α Mean (± standard deviation) (*p < .05)

NDI: Neck Disability Index, VAS: Visual Analogue Scale for Pain, DGA: Vertical Distance from Ground to Shoulder Apex, CVA: Craniovertebral Angle, CRA: Cranial Rotation Angle

*Significant differences between the thoracic and abdominal breathing groups and between the thoracic and thoracoabdominal groups (p < .05)

Paired t-test results: †Significant differences between pre-intervention and post-intervention within the group (p < .05)

2. VAS for Neck and Shoulder pain

The pre- and post-intervention results were similar in all breathing groups (p > .05). Furthermore, no significant difference was observed among the three groups (p > .05) (Table 2).

3. Vertical DGA

A comparison of pre- and post-intervention in all breathing groups revealed a significant decrease in the values after the intervention (p < .05). Nevertheless, no significant difference was noted among the three groups (p > .05) (Table 2).

4. Measurement of FHP

1) CVA

A comparison of the pre- and post-intervention for the abdominal breathing group and the thoracoabdominal breathing group revealed a significant increase in the values after the intervention (p < .05). Furthermore, a significant difference was observed among the three groups (p < .05). The changes in the values before and after the intervention for the abdominal breathing group, and the thoracoabdominal breathing group showed a significant difference compared to the changes in the thoracic breathing group (p < .05) (Table 2).

2) CRA

A comparison between pre- and post-intervention for the abdominal breathing group and the thoracoabdominal breathing group revealed a significant decrease after the intervention (p < .05). In addition, a significant difference was observed among the three groups (p < .05). The changes in the values before and after the intervention for the abdominal breathing group and the thoracoabdominal breathing group showed a significant difference compared to the changes in the thoracic breathing group (p < .05) (Table 2).

5. Mechanical Properties of Muscles

In the thoracic breathing group, the tension and stiffness of the upper trapezius muscle decreased significantly after the intervention (p < .05), while the tension and stiffness of the sternocleidomastoid muscle increased significantly (p < .05). In the abdominal breathing group, the tension of the upper trapezius and levator scapulae muscles decreased significantly after the intervention, and the elasticity of the levator scapulae muscle increased significantly (p < .05). In the thoracoabdominal breathing group, the elasticity of the lower trapezius muscle increased significantly after the intervention (p < .05). An analysis of the changes in the mechanical properties among the groups showed a statistically significant difference in the mechanical properties of the sternocleidomastoid muscle among the three groups (p < .05). In particular, the tension of the sternocleidomastoid muscle in the thoracic breathing group showed a significant difference compared to that in the abdominal breathing group and the thoracoabdominal breathing group. Moreover, the stiffness of the sternocleidomastoid muscle in the thoracic breathing group also showed a significant difference compared to that in the abdominal breathing group (p < .05) (Table 3).

Comparison of mechanical properties of muscles before and after intervention within and between groups

Muscle Property Thoracic breathing group Abdominal breathing group Thoracoabdominal breathing group
Pre Post Pre Post Pre Post
Lower Trapezius Tension(㎐) 14.38α (2.02) 14.44 (1.38) 14.96 (2.04) 14.44 (1.37) 15.73 (1.37) 15.35 (1.11)
Stiffness(N/m) 238.46 (73.60) 250.50 (55.90) 236.46 (58.26) 235.60 (40.26) 263.17 (35.34) 267.07 (36.21)
Elasticity .95 (.22) .93 (.17) .92 (.18) .98 (.11) .90 (.14) 1.02† (.14)
Upper Trapezius Tension(㎐) 15.41 (1.45) 13.97† (1.29) 15.13 (1.44) 14.12† (1.70) 15.30 (1.49) 14.28 (1.44)
Stiffness(N/m) 262.17 (44.73) 226.71† (35.64) 245.53 (56.07) 237.60 (40.59) 246.75 (43.79) 237.92 (38.12)
Elasticity .97 (.12) .97 (.19) .97 (.20) .96 (.16) .88 (.14) .98 (.20)
Levator Scapulae Tension(㎐) 13.00 (1.66) 13.45 (1.40) 13.05 (1.21) 12.32† (1.14) 13.71 (2.31) 12.71 (.83)
Stiffness(N/m) 196.32 (40.62) 212.57 (30.63) 185.57 (37.24) 186.82 (36.53) 198.96 (62.34) 188.89 (36.68)
Elasticity 1.03 (.13) 1.13 (.18) .96 (.16) 1.07† (.12) 1.00 (.14) 1.04 (.16)
Sternocleidomastoid Tension(㎐) 12.80 (.97) 13.50† (.89) 13.42 (1.43) 13.16* (1.07) 13.48 (1.48) 13.04* (.95)
Stiffness(N/m) 177.67 (24.48) 206.71† (16.93) 200.64 (32.04) 198.39* (23.25) 193.10 (34.65) 199.67 (18.39)
Elasticity 1.15 (.13) 1.25 (.16) 1.24 (.11) 1.30 (.15) 1.18 (.22) 1.20 (.17)
Pectoralis Major Tension(㎐) 14.38 (1.55) 14.31 (1.36) 15.11 (2.20) 14.13 (1.78) 16.36 (1.78) 15.31 (1.45)
Stiffness(N/m) 235.14 (48.32) 237.10 (40.02) 256.96 (65.44) 235.14 (43.45) 285.14 (71.66) 257.14 (35.72)
Elasticity 1.01 (.16) 1.10 (.14) 1.06 (.21) 1.09 (.15) 1.02 (.23) 10.01 (.17)

α Mean (± standard deviation) (*p < .05)

*Significant differences between the thoracic and abdominal breathing groups and between the thoracic and thoracoabdominal breathing groups (p < .05)

Paired t-test results: †Significant differences between the pre-intervention and post-intervention within the group (p < .05)
Ⅳ. Discussion

This study examined the effects of breathing patterns during exercise on 42 subjects with UCS, categorizing them into thoracic, abdominal, and thoracoabdominal breathing groups. The intra-rater and inter-rater ICC values for the reliability of muscle measurements using the Myoton ranged between .74 and .97. The results obtained show that the Myoton has a good to excellent intra-rater and inter-rater reliability for measuring the tone, stiffness, and elasticity of muscle [39,40]. These results can be summarized as follows. 1) A comparison of the pre-post intervention changes revealed significant differences in the CVA and CRA values within the abdominal and thoracoabdominal breathing groups. Regarding the muscle characteristics, significant differences were observed in the tension and stiffness of the sternocleidomastoid muscle within the thoracic breathing group. 2) A comparison of the three groups revealed significant differences in the CVA and CRA values in the abdominal and thoracoabdominal breathing groups compared to those in the thoracic breathing group. Regarding muscle characteristics, the tension and stiffness of the sternocleidomastoid muscle in the abdominal breathing group showed significant differences compared to the thoracic breathing group. Furthermore, the tension of the sternocleidomastoid muscle in the thoracoabdominal breathing group showed significant differences compared to the thoracic breathing group.

After conducting breathing technique-based exercises in patients with rotator cuff injuries and altered neck and shoulder posture, followed by a range of motion and muscle strengthening exercises, significant effects on the CVA were observed within the abdominal breathing, thoracic breathing, and thoracoabdominal breathing groups. Nevertheless, no significant differences were found between the groups [15]. Furthermore, the CRA decreased significantly more in the thoracic breathing and thoracoabdominal breathing groups than in the abdominal breathing group. This suggests that chest expansion exercises influenced active movements around the neck and shoulder muscles [15]. In this study, however, significant differences in the CVA and CRA were observed only between the abdominal and the thoracoabdominal breathing groups. This suggests that combining breathing exercises with exercises aimed at improving upper crossed syndrome may be more effective in aligning the upper and lower cervical vertebrae by reducing the activation of the accessory breathing muscles such as the sternocleidomastoid, while increasing the activation of deep neck flexor muscles.

The sternocleidomastoid muscle tends to be more activated in subjects using an upper thoracic breathing pattern [41]. Furthermore, patients with cervical headaches often exhibit increased muscle tension and stiffness around the neck because of FHP, resulting in excessive activation of the sternocleidomastoid muscle [42]. Exercises combining head-neck flexion movements with lateral breathing can reduce the activation of the accessory muscle, the sternocleidomastoid, during inhalation [43]. In the present study, significant results were observed in the pre- to post-intervention changes in tension and stiffness in the sternocleidomastoid muscle within the thoracic breathing group. The comparisons among the three groups revealed significant changes in tension with the abdominal and thoracoabdominal breathing groups, showing significant differences compared to the thoracic breathing group. Stiffness also showed significant changes in the abdominal breathing group, showing significant differences from the thoracic breathing group. This suggests that activation of the sternocleidomastoid muscle occurred during deep neck flexor strengthening exercises in the thoracic breathing group. The sternocleidomastoid muscle in daily activities may have contributed to the adverse effects.

In the case of the abdominal and thoracoabdominal breathing groups, sternocleidomastoid muscle activation was suppressed during deep neck flexor strengthening exercises. On the other hand, the ongoing use of the sternocleidomastoid muscle in daily activities offset the improvement effects, resulting in no significant differences in the pre- and post-intervention values. This confirms the consistency with previous studies and results, showing that abdominal breathing and thoracoabdominal breathing suppressed the activation of the sternocleidomastoid muscle during deep neck flexor strengthening exercises.

The NDI and VAS for pain were similar among the groups. The application of Pilates breathing in cervical stabilization exercises confirmed a reduction in pain through postural correction for FHP [44]. Increased muscle activation of the sternocleidomastoid suggests decreased muscle activation of the deep neck flexors, indicating reduced neck stability that may contribute to the development of neck pain [45]. Furthermore, a more than 50° decrease in the CVA is associated with pain [46]. This experiment showed no changes in the pre- and post-values for the NDI and the VAS for pain in all breathing groups. This was attributed to the subjects being mild patients with a CVA of 50° or more and did not experience severe pain.

The McKenzie, Kendall, and self-stretching exercise groups all showed similar effects in improving rounded shoulders, indicating positive impacts on correcting FHP [47]. The study confirmed that exercises targeting the pectoralis minor improve the rounded shoulder posture [48]. Lower trapezius strengthening exercises improve functional disability and shoulder pain in patients with rounded shoulders [49]. Subjects who perform chest breathing frequently use the accessory respiratory muscle, the sternocleidomastoid. On the other hand, those who perform abdominal breathing rely less on the sternocleidomastoid muscle [45]. In this study, however, there was no significant difference in the DGA between the groups before and after the intervention. This suggests that although the deep cervical flexor exercises applied in this study directly improved the sternocleidomastoid muscle, differences in breathing patterns primarily affected the cervical tissues rather than the shoulder joint. Therefore, the exercises did not directly affect the pectoralis minor, upper trapezius, lower trapezius, and serratus anterior muscles, which are related to rounded shoulder posture.

This study had several limitations. First, the study focused on subjects with mild UCS, which limited significant changes in the measured values. In addition, the study did not consider gender balance, making it challenging to generalize the findings to all patients with UCS. Second, there were variations in breathing awareness and exercise capacity among subjects because of personal abilities and skills. Owing to differences in exercise abilities among the subjects, there were examples where breathing control during exercise was not consistent. Third, the exercise intensity could not be applied equally across all groups during the exercise sessions because of subject differences in exercise abilities among the subjects. Last, this study was conducted over only four weeks with sessions held twice weekly, preventing long-term observations and follow-up investigations. Considering these limitations, future studies should expand the sample size and investigate diversity factors, such as age and gender. In addition, incorporating objective measurement tools and extending the intervention period should be explored and applied to collect more accurate data and improve the reliability of the results. Addressing these limitations will help set the direction for future research.

Ⅴ. Conclusion

This study examined the association between breathing methods and exercise in 42 subjects with UCS. Subjects were classified randomly into the thoracic, abdominal, and thoracoabdominal breathing groups. After performing exercises according to breathing methods, significant improvements were observed in indicators related to UCS, such as the DGA, CVA, CRA, and the tension and stiffness of the sternocleidomastoid muscle. The abdominal breathing exercise group had the most significant impact on FHP. Among them, the abdominal breathing exercise group had the most significant effect on the FHP. Overall, exercise with abdominal breathing is recommended for patients with severe UCS. This study is significant in examining the effectiveness of adding breathing intervention, not just exercise intervention, for UCS.

Acknowledgments

This research was supported by 2024 eulji university University Innovation Support Project grant funded.

References
  1. Kang JH, Park RY, Lee SJ, et al. The effect of the forward head posture on postural balance in long time computer based worker. Annals of rehabilitation medicine. 2012;36(1):98.
    Pubmed KoreaMed CrossRef
  2. Lau KT, Cheung KY, Chan MH, et al. Relationships between sagittal postures of thoracic and cervical spine, presence of neck pain, neck pain severity and disability. Manual Therapy. 2010;15(5):457-62.
    Pubmed CrossRef
  3. An SH. Therapeutic approaches for chronic neck pain patients. Coaching Competence Development Journal. 2005;7(3):15-21.
  4. Yip CHT, Chiu TTW, Poon ATK. The relationship between head posture and severity and disability of patients with neck pain. Manual Therapy. 2008;13(2):148-54.
    Pubmed CrossRef
  5. Izraelski J. Assessment and treatment of muscle imbalance: The Janda approach. The Journal of the Canadian Chiropractic Association. 2012;56(2):158.
  6. Kim CS, Kim SG. The effect of strengthening on scapul ar stabilizer muscles for the rounded shoulders. PNF and Movement. 2013;11(2):49-56.
  7. Kim KS. Immediate effects of shoulder joint stretching with and without vibration on cervical range of motion, functional movement, and pain. Seoul. EwhaWomans University Graduate School of Education. 2018.
  8. Song SH. Clinical efficacy of manual therapy for patients with upper cross syndrome. Daejeon. Graduate School of Health, Eulji University. 2019.
  9. Han HK, Choi YJ, Jung SH, et al. Intra- and inter-rater reliability of myoton measurements of erector spinae muscles in young and elderly adults. KSIM. 2021;9(1):193-202.
  10. Sarig-Bahat H. Evidence for exercise therapy in mechanical neck disorders. Manual therapy. 2003;8(1):10-20.
    Pubmed CrossRef
  11. Wong CK, Coleman D, Song J, et al. The effects of manual treatment on rounded-shoulder posture, and associated muscle strength. Journal of Bodywork and Movement Therapies. 2010;14(4):326-33.
    Pubmed CrossRef
  12. Arlotta M, Lovasco G, McLean L. Selective recruitment of the lower fibers of the trapezius muscle. J Electromyogr Kinesiol. 2011;21(3):403-10.
    Pubmed CrossRef
  13. Lee JC. Effect of shoulder stabilization exercise and McKenzie exercise on forward head posture. JCCT. 2019;5(4):227-35.
  14. Park TJ. Comparison of muscle activity in serratus anterior and trapezius during shoulder stabilization exercises in male college students. Seoul. Korea National Sport University. 2019.
  15. Lee JC. The effects of abdominal respiratory exercise by forward head posture adult's respiratory function and respiratory muscle strength. Gyeongsan. Daegu University. 2015.
  16. Cho YH. Effects of crocodile breathing exercise on pain, trunk muscle tension, and muscle stiffness in patients with nonspecific low back pain. J Korean Soc Phys Med. 2019;14(2):117-24.
    CrossRef
  17. Baek KM, Lee SB, Jeon MN, et al. Pilates breathing on the activity of trunk stabilizer muscles during the movements of pilates chair exercise. KSIM. 2022;10(4):187-97.
  18. Segal NA, Hein J, Basford JR. The e ffects of Pilates training on flexibility and body composition: an observational study. Archives of Physical Medicine and Rehabilitation. 2004;85(12):1977-81.
    Pubmed CrossRef
  19. Latey P. The pilates method: history and philosophy. Journal of Bodywork and Movement Therapies. 2001;5(4):275-82.
    CrossRef
  20. Ha NR. Effects of breathing exercise methods on postural and muscle characteristics in patients with rotator cuff injuries and altered neck and shoulder posture. Daejeon. Graduate School of Health, Eulji University. 2014.
  21. Son HH. Effects of spinal stabilization exercise combined with abdominal breathing on balance ability and oswestry disability index in patients with low back pain. J Korean Soc Phys Med. 2015;10(1):107-13.
    CrossRef
  22. Song KJ, Choi BW, Kim SJ, et al. Cultural adaptation and validation of the Korean version of the neck disability index. Kor Acad Ortho Man Phys Ther. 2009;44(3):350-9.
    CrossRef
  23. Vernon H, Mior S. The neck disability Index: a study of reliability and validity. Journal of manipulative and physiological therapeutics. 1991;14(7):409-15.
  24. Shim SY, Park HJ, Lee JM, et al. Review of pain assessment tools. Korean Journal of Acupuncture. 2007;24(2):77-97.
  25. Sahrmann S. Diagnosis and treatment of movement impairment syndromes-e-book. Elsevier Health Sciences. 2001.
  26. Kim EJ, Kim JW, Park BR. Effects of sling exercise program on muscle activity and cervical alignment in forward head posture. Jour. of KoCon.a. 2011;11(11):213-20.
    CrossRef
  27. Mullix J, Warner M, Stokes M. Testing muscle tone and mechanical properties of rectus femoris and biceps femoris using a novel hand held MyotonPRO device: relative ratios and reliability. Working Papers in the Health Sciences. 2012;1(1):1-8.
  28. Choi SA. Effects of one-time stretching and myofascial release on the mechanical properties of back and leg muscles in women in their 20s who wear high heels. Pusan. Graduate School of Pusan National University. 2018.
  29. Aird L, Samuel D, Stokes M. Quadriceps muscle tone, elasticity and stiffness in older males: reliability and symmetry using the MyotonPRO. Arch Gerontol Geriatr. 2012;55(2):e31-9.
    Pubmed CrossRef
  30. Chuang LL, Wu CY, Lin KC. Reliability, validity, and responsiveness of myotonometric measurement of muscle tone, elasticity, and stiffness in patients with stroke. Arch Phys Med Rehabil. 2012;93(3):532-40.
    Pubmed CrossRef
  31. Smaczniak C, Immink RG, Muiño JM, et al. Characterization of MADS-domain transcription factor complexes in arabidopsis flower development. Proceedings of the National Academy of Sciences. 2012;109(5):1560-5.
    Pubmed KoreaMed CrossRef
  32. Bailey L, Samuel D, Warner M, et al. Parameters representing muscle tone, elasticity and stiffness of biceps brachii in healthy older males: symmetry and within-session reliability using the MyotonPRO. Journal of Neurological Disorders. 2013;1(1):1-7.
    CrossRef
  33. Adler-Storthz K, Kendall C, Kennedy RC, et al. Biotin-avidin-amplified enzyme immunoassay for detection of herpes simplex virus antigen in clinical specimens. J Clin Microbiol. 1983;18(6):1329-34.
    Pubmed KoreaMed CrossRef
  34. Shim JE, Jang SB. Effects of abdominal breathing on anxiety in pregnant women with early labor. Korean J Women Health Nurs. 2006;12(2):106-14.
    CrossRef
  35. de Mayo T, Miralles R, Barrero D, et al. Breathing type and body position effects on sternocleidomastoid and suprahyoid EMG activity. J Oral Rehabil. 2005;32(7):487-94.
    Pubmed CrossRef
  36. Borstad JD, Ludewig PM. The effect of long versus short pectoralis minor resting length on scapular kinematics in healthy individuals. Journal of Orthopaedic & Sports Physical Therapy. 2005;35(4):227-38.
    Pubmed CrossRef
  37. Hardwick DH, Beebe JA, McDonnell MK, et al. A comparison of serratus anterior muscle activation during a wall slide exercise and other traditional exercises. J Orthop Sports Phys Ther. 2006;36(12):903-10.
    Pubmed CrossRef
  38. Kisner C, Colby LA, Borstad J. Therapeutic exercise: foundations and techniques. Fa Davis. 2017.
  39. Taş S, Aktaş A, Tufek MT, et al. MyotonPRO is a reliable and repeatable tool for measuring mechanical properties of the upper limb muscles in patients with chronic stroke. Physikalische Medizin, Rehabilitationsmedizin, Kurortmedizin. 2023;33(05):286-92.
    CrossRef
  40. Lettner J, Królikowska A, Ramadanov N, et al. Evaluating the reliability of myotonpro in assessing muscle properties: a systematic review of diagnostic test accuracy. Medicina (Kaunas). 2024;60(6).
    Pubmed KoreaMed CrossRef
  41. Cagnie B, Danneels L, Cools A, et al. The influence of breathing type, expiration and cervical posture on the performance of the cranio-cervical flexion test in healthy subjects. Man Ther. 2008;13(3):232-8.
    Pubmed CrossRef
  42. Park SH, Jung DG, Yoon JH. Analysis of Muscle Characteristics, posture, and muscle activity in cervicogenic headache patients. JKAIS. 2022;23(6):137-43.
    CrossRef
  43. Lee HJ, Kwon NY, Kwon YJ, et al. Effects of diaphragmatic breathing and head-neck flexion exercise on sternocleidomastoid muscle activity and respiratory function in young adults with forward head posture. J Kor Acad Cardiorespir Phys Ther. 2014;2(1):1-7.
  44. Lee SY, Kim KY, Lim KD, et al. Effects of cervical stabilization exercise with pilates breathing on muscle endurance and grip strength in forward head posture. J Korean Acad Ther. 2023;15(1):25-31.
    CrossRef
  45. Won JI. Effects of breathing patterns on sternocleidomastoid and deep cervical flexor muscle thickness during head and neck flexion. Journal of Korean Society of Professional Physical Therapists. PTK. 2018;25(2):44-52.
    CrossRef
  46. Kadu DV, Shetye JV, Mehta A. Comparison of peripheral arterial blood pressure in individuals with and without forward head posture. Journal of Health and Allied Sciences NU. 2019;9(03):098-103.
    CrossRef
  47. Lee DY. Effects of forward head posture correction exercise on rounded shoulder posture and respiratory function. Gyeongsan. Daegu University. 2015.
  48. Choi JW, Jung YS, Kwon OG, et al. Effects of intervention for reducing upper trapezius activity in adults with rounded shoulders on posture, muscle activity, and neck disability index. Kor Acad Ortho Man Phys Ther. 2020;26(1):9-18.
  49. Choi JY. Effects of lower trapezius strengthening exercise on pain and disability in shoulder pain patients with rounded shoulders, graduate school of health sciences. Chuncheon. Hallym University. 2016.

November 2024, 19 (4)
Full Text(PDF) Free

Social Network Service

Services

Cited By Articles
  • CrossRef (0)

Funding Information