• Journal of Oral Medicine and Pain
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• v.22 no.1
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• pp.95-109
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• 1997

The purpose of this research is to investigate the influence on mandibular movements and TMJ sounds with changes of head and neck posture. For the research, twenty patients who had complained of TMJ sounds without any other symptoms of cranio-mandibular disorders, were selected as subjects for measurements of TMJ sounds, and radiographs on transcranial view of TMJ were taken on ten of the subjects. From NHP, UHP, DHP and FHP, aspects of mandibular movement and TMJ sound were investigated from each posture. Aspects of mandibular movement and TMJ sound were observed by measuring total vibration energy(Integral), peak amplitude, maximum amound of mouth opening, and TMJ sound-emitting point using Sonopak for windows (version 1.33) and Bio-EGN(Bioresearch Inc. WI. U.S.A.). Head and neck movement-measuring instrument, CROM(perfomance attainment Inc. U.S.A.) was to maintain even head posture. Degrees of inclination of UHP and DHP were determined at 30' and distance of FHP was 4cm. The results obtained were as follows. 1. Total vibration energy and peak amplitude of TMJ sounds were decreased more on UHP and on UHP and increased more on DHP and FHP than that on NHP. 2. At the maximum mouth opening, distance of TMJ sound-emitting point were decreased more on UHP and increased more on DHP and FHP than that on NHP. 3. The amounts of the maximum mouth opening were increased more on UHP and decreased more on DHP and FHP than that on NHP. 4. For the changes of the head posture with mouth opening observed in radiograph, condylar head was positioned more lower-anteriorly on UHP, and more upper-posteriorly on DHP and FHP than that on NHP. From the results obtained as above, considering positive influence of the change of head and neck posture, avoiding down-head and forward-head posture, and recommending upper- head posture can prevent the progress of temporomandibular disorder and lead to successful treatment for the patients with temporomandibular joint sounds.

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.279-284
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• 2013

The purpose of this study was to determine the effect of head posture and respiratory pattern on muscle activities of sternocleidomastoid (SCM) and scalene during maximal respiration. The seventeen subjects with upper-costal breathing pattern were participated in this study. Surface electromyography was used to measure the muscles activities of SCM and scalene. The volume and velocity of inspiration were monitored by using the spirometer in each subject. Each subject was performed the 3-cycle of respiration in each condition. The mean values of three peak muscle activity in each muscle were used in the data analysis. A2 (head posture: forward head posture: FHP vs. neutral posture) X 2 (breathing pattern: costal vs. diaphragmatic) repeated-measures analysis of variance (ANOVA) was used to compare the normalized muscle activities of the SCM and scalene. The results showed that the muscle activities of SCM and scalene in diaphragmatic breathing were significantly lower than those in costal breathing for each head posture (p<.0125). The muscle activities of SCM in neutral position were lower than those in forward head position during costal breathing (p<.0125). The diaphragmatic breathing in neutral position of head is recommended to decrease the tension of the accessory inspiratory muscles during respiration in neck-pain patients with FHP.

• The Journal of Korean Physical Therapy
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• v.35 no.3
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• pp.83-88
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• 2023

Purpose: This study was to investigate the effect of forward head posture (FHP) and round shoulder posture (RSP) on changes in muscle activities according to shoulder flexion and abduction tasks. Methods: Twenty-two male subjects with no history of neurological, musculoskeletal surgery or injuries, or pain in the spine region within the previous 3-month periods were recruited for this study. Craniovertebral angle (CVA) and Scapula Index were measured before performing 90° abduction and flexion tasks holding a 3kg dumbbell. Muscle activities were measured during the tasks. All measurements except height of the acromion were carried out in a sitting position at the height of the subject's knee angle of 90 degrees, and two tasks were randomly performed with the arm that the subject mainly use to throw the ball. The abduction and flexion angles were checked by the examiner using a goniometer beside the subject. Results: Correlation coefficient analysis between Scapular Index and upper trapezius muscle activity during shoulder abduction task showed significant positive correlation. No significant correlation was observed between CVA, Scapular Index, and other muscle activities. Conclusion: FHP showed increased muscle activation, making it difficult to change muscle activity under lower loads, and RSP was correlated with UT activation in shoulder abduction. Therefore, in the RSP, the loaded shoulder abduction is considered a potential risk factor for increasing shoulder muscle tension. This paper proposes an approach to treating RSP before FHP.

• The Journal of Korean Physical Therapy
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• v.32 no.5
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• pp.319-324
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• 2020

Purpose: This study was to investigate the effect of dorsal neck muscle fatigue on the cervical range of motion (CROM) and proprioception in adults with the forward head posture (FHP). Methods: Thirty pain-free subjects were enrolled in this study. All subjects were measured the forward head angle by taking the capture of the sagittal plane of their upper body to determine the FHP. Subjects were distributed into two groups: the FHP group (n=14) and Control group (n=16). All subjects were measured the CROM and the Head repositioning accuracy (HRA) for joint proprioception before and after inducing muscle fatigue of the dorsal neck. The CROM and HRA were measured in neck flexion, extension, right-left lateral flexion, and right-left rotation. Sorenson's test was used to induce muscle fatigue of the dorsal neck. Results: Total CROMs were significantly decreased after dorsal neck muscle fatigue in both groups (p<0.05). Total HRAs were significantly increased after dorsal neck muscle fatigue in the FHP group (p<0.05), but there were no significant differences in the control group (p>0.05). Total CROM changes were not significant differences between groups (p>0.05), but total HRA changes were significant differences between groups (p<0.05) except for right and left lateral flexion (p>0.05). Conclusion: Immediate CROM and proprioception reduction after the dorsal neck muscle fatigue were observed in adults with the FHP. Therefore, FHP can significantly affect the CROM and positioning consistency of cervical proprioception.

• The Journal of Korean Physical Therapy
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• v.32 no.6
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• pp.378-382
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• 2020

Purpose: This study aimed to examine the effects of forward head posture on the flexion-relaxation ratio (FRR) and muscle activity during sustained neck flexion and to investigate the correlation between craniovertebral angle and FRR. Methods: Nineteen subjects participated in this study and were allocated to a forward head posture (FHP) group or a non-forward head posture (NFHP) group. Craniovertebral angle (CVA) and FRR were measured in all subjects, and all participants performed a standardized cervical flexion-extension movement in two phases: Phase I, sustained cervical full flexion for 5s; and Phase II, cervical extension with the return to the starting position for 5s. The value of CVA has calculated three times, and the value of FRR was measured three times in order to obtain the mean value. Results: FRR values in the FHP and NFHP group were significantly different (p<0.05). Phase I was significantly different, but the Phase II was not significantly different between the FHP and NFHP group (p>0.05). There was a significant correlation between the muscle activity of Phase I and CVA (p<0.05). However, FRR and the muscle activity of the Phase II were not a significant correlation with the CVA (p>0.05). Conclusion: FHP increases the muscle activity of the cervical erector spinae during sustained neck flexion and reduces FRR, which can cause fatigue in the cervical erector spinae. In addition, for those with a smaller CVA, muscle activity of the cervical erector spinae is increased during sustained neck flexion, which can increase neck muscle tension.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.71-77
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• 2009

Purpose: This study assessed the differences in the forward head posture (FHP), cervical range of motion, and headache clinical parameters in episodic tension-type headache (ETTH) subjects, chronic tension-type headache (CTTH) subjects, and healthy controls (university students). Methods: Fifteen CTTH subjects, 15 ETTH subjects and 15 controls without headache were examined. Side-view images of each group were taken in both the sitting and standing positions, in order to assess the FHP by measuring the craniovertebral angle. The CROM was used to measure the cervical range of motion. A headache diary was kept for 4 weeks to assess the headache intensity, frequency, and duration. Results: The craniovertebral angle was smaller, ie, there was a greater FHP, in the CTTH and ETTH subjects than in the healthy controls in both the sitting and standing positions (p<0.05). The CTTH and ETTH subjects showed a lower cervical range of motion than the healthy controls in the total range of motion as well as in the half-cycles (p<0.05). Conclusion: The increased FHP and decreased cervical range of motion might be a contributing factor in the initiation of tension-type headache.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.436-445
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• 2022

Objective: Deformation of soft tissues around the neck and scapularcan caused by forward head posture(FHP), which has an uncomfortable effect on biomechanical changes in the scapula as well as functional disorders of the shoulder. However, studies related to direct FHP, biomechanical changes in the scapulafunction, and shoulder pain and disorder have not yet been conducted. Therefore, purpose of this study is to effect of decresedthe FHP on the shoulder function of the sacpular biomechanical examine the change in the shoulder painand disorder. Design: A randomized controlled trial Methods: The participants were 32adults(23.03±3.90 years) recruited and redivided randomly into Forward head posture corrective exercise(FHPCE) vs Control. The FHPCE group was proceeded according to the over load principle through 2steps biofeedback exercise and corrective exercise(n=16). The control (n=16) was TENS did not operated and padding 20 minute. This study was conducted 3 times a week for 4a weeks. Results: FHPCE group is improve in the results of craneocervical angle(p<0.05, 95% CI: 0.352, 4.073). In Mechanical changes of scapula in the shoulder flexion more significant improvement in FHPCE than control group[Axis X(p<0.05), Y(p<0.01), Z(p<0.01)], and shoulder abductionmore significant improvement in FHPCE than control group[xis X(p<0.01)], as well FHPCE showed significant increased in the results in the shoulder pain(p<0.05, 95% CI: -13.244, -1.566) Conclusions: This study suggected that FHP affects the biomechanical changes of the shoulder, and a new method for shoulder pain intervention

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.1954-1959
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• 2020

Background: Due to aging, blood flow rate decreases, also posture and chewing habit may be changed. Objective: To identify that changes in blood velocity in the common carotid arteries (CCAs) in old persons with unilateral chewing habit (UCH) and forward head posture (FHP) in the elderly. Design: An observational cross-sectional study. Methods: Chewing habits, FHP, and CCAs velocities were assessed in 85 elderly subjects. Chewing habits were measured by visual observation. CCAs measured the peak systolic velocity (PSV), end-diastolic velocity (EDV), minimum diastolic velocity, and resistivity index. The subjects were divided into UCH and bilateral chewing habit groups depending on chewing habit. The subjects were also divided into >49 degrees and <49 degrees for comparison of blood flow between the left and right CCAs. Results: In the UCH, the chewing side had significantly higher EDV (P=.003), PSV (P=.023) than the non-chewing side. There was no significant difference in velocity between the CCAs in the FHP. Conclusion: This study shows that the blood flow velocity of the chewing side of UCH was higher, and unilateral chewing affects the CCAs velocity and thus highlight the importance of chewing habit in the elderly than head posture.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.1
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• pp.83-89
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• 2015

PURPOSE: The purpose of this study was to investigate the vital capacity and maximal voluntary ventilationin subjects with forward head posture (FHP). METHODS: Twenty-eight subjects participated in this study (normal 14, FHP 14) and were resident in B city. The mean age, height and weight of subjects was 22.80yrs, 169.36cm and 62.79kg. Subjects were asked to breath maximally for FVC and repeatedly for MVV during 12 seconds. The variables of data were collected as follows: Forced Vital Capacity(FVC), Forced Expiratory Volume in One Second($FEV_1$), $FEV_1$/FVC, Maximal Voluntary Ventilation(MVV). Each trial was performed by 3 times and we used the means to analyze the data. The mann-whitney U test and independent t-test were used to compare the vital capacity between normal and FHP subjects. All statistical analyses were performed using SPSS 21.0 for window versionand p-values less than 0.05 were used to identify significant differences. RESULTS: The FVC, $FEV_1$, $FEV_1$/FVC and MVV of FHP subjects were decreased more than that of normal subjects and the difference was statistically significant between two groups. CONCLUSION: The vital capacity of subjects with FHP was generally lower than normal subjects. This study shows that the vital capacityof subjectswith FHP could be decreased due to the bad neck posture that weakens the respiratory accessory muscles of neck.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.2
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• pp.89-94
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• 2015

PURPOSE: The aim of this study was to determine the effect of device considering Mckenzie type for the subjects with forward head posture (FHP). METHODS: The subjects were 35 patients with FHP (mean age was $23.7{\pm}2.8$ years; mean height; $172.1{\pm}11.7$, mean weight; $65.8{\pm}13.9$, mean NDI(Neck Disability Index; $3.7{\pm}3.2$, mean FHP; $6.7{\pm}2.2$). We measured the posture with the Body style S-8.0(LU Commerce, South Korea) to evaluate the FHP. We collected the surface EMG(Myosystem 1400, Noraxon, USA) data to quantify changes in normalized activation levels of muscles in SternoCleidoMastoid muscle(SCM), Scalenus Anterior(SA), Trapezius upper fiber(TU) and Splenius Cervicis(SC), during the subjects were instructed to glide their head into a "chin-in" position for a retraction without and with device. RESULTS: The condition with device significantly decreased the %RVC of SA($90.84{\pm}40.54$), SCM($74.98{\pm}43.65$) and TU($67.60{\pm}47.83$) compared to the condition without device(SA;$100.39{\pm}56.32$, SCM;$119.03{\pm}109.26$, Trapezius;$80.55{\pm}39.27$). But the %RVC of capitis($65.87{\pm}47.83$) with device was increased($70.82{\pm}52.78$). There was significant difference in the %RVC between SCM and Trapezius muscle in two conditions. CONCLUSION: New device for FHP reduces the EMG activities of the TU, SCM and SA muscle. We have to develop the function of feedback to facilitate the motion in the future.