• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.155-160
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• 2010

Purpose: The purpose of this study was to evaluate how phoria variations would vary with head positions, as well as to review the need to differentiate prism placement over either eye in a relation to the imbalance of the extraocular muscle. Methods: This study was carried out with 44 males (88 eyes) and 16 females (32 eyes) aged between 20 and 30. For all subjects, testings were performed using cover test, subjective refraction, phoria and vergence test. To analyze phoria variations comparatively for the head tilt test and the face turn test, phoria deviation were measured using the von Graefe. Results: For the phoria variation related with head tilt and face turn, a significant difference was observed in the group judged to be abnormal on the horizontal phoria of Morgan' norm (p<0.05); especially in patients who needed near prescription of Sheard's criterion, a higher variation was observed (p<0.05). The abnormal group was composed of patients who needed distance prescription of Sheard's criterion and ones who did not need the prescription, all of whom showed phoria variations, but the mean value was less than the near. Conclusions: With regard to the head tilt and face turn related phoria level, the patients who needed near horizontal prism prescription of Sheard's criterion showed a remarkably higher variation. Altogether, it is deemed to check whether extraocular muscles are ill-balanced in both eyes previously to determine the prism power on phoria level to the end that each of prism powers may be accurately determined.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.325-332
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• 2006

The dynamic responses of human standing postural control were investigated when subjects were exposed to long-term horizontal vibration. It was hypothesized that the motion of standing posture complexity mainly occurs in the mid-sagittal plane. The motor-driven support platform was designed as a source of vibration. The AC Servo-controlled motors produced anterior/posterior (AP) motion. The platform acceleration and the trunk angular velocity were used as the input and the output of the system, respectively. A method was proposed to identify the complexity of the standing posture dynamics. That is, during AP platform motion, the subject's knee, hip and neck were tightly constrained by fixing assembly, so the lower extremity, trunk and head of the subject's body were individually immovable. Through this method, it was assumed that the ankle joint rotation mainly contributed to maintaining their body balance. Four subjects took part in this study. During the experiment, the random vibration was generated at a magnitude of $0.44m/s^2$, and the duration of each trial was 40 seconds. Measured data were estimated by the coherence function and the frequency response function for analyzing the dynamic behavior of standing control over a frequency range from 0.2 to 3 Hz. Significant coherence values were found above 0.5 Hz. The estimation of frequency response function revealed the dominant resonance frequencies between 0.60 Hz and 0.68 Hz. On the basis of our results illustrated here, the linear model of standing postural control was further concluded.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.120-126
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• 2009

The purpose of this study was to develop a visibility evaluation system for cabin type combine. Human's field of view was classified into five levels (perceptive, effective, stable gaze, induced, and auxiliary) depending on rotation of human's head and eye. Divider, reaper lever, gearshift, dashboard, and conveying part were considered as major viewpoints of combine. Visibilities of combine was evaluated quantitatively using the viewpoints and the human's field of view levels. The visibility evaluation system for cabin type combine was consisted of a laser pointer, stepping motors to control the direction of view, gyro sensors to measure horizontal and vertical angle, and I/O interface to acquire the signals. Tests were conducted with different postures ('sitting straight', 'sitting with $15^{\circ}$ tilt', 'standing straight', and 'standing with $15^{\circ}$ tilt'). The LSD (least significant difference) multiple comparison tests showed that the visibilities of viewpoints were different significantly as the operator's postures were changed. The results showed that the posture at standing with $15^{\circ}$ tilt provided the best visibility for operators. The divider of the combine was invisible due to blocking with the cabin frame at many postures. The reaper lever showed good visibilities at the postures of sitting or standing with $15^{\circ}$ tilt. The gearshift, the dashboard, and the conveying part had reasonable visibilities at the posture of sitting with $15^{\circ}$ tilt. However, most viewpoints of the combine were out of the stable gaze field of view level. Modifications of the combine design will be required to enhance the visibility during harvesting operation for farmers' safety and convenience.

• Journal of Korean Physical Therapy Science
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• v.26 no.2
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• pp.38-45
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• 2019

Purpose: This study purpose to comparison the effects of passive scapular alignment exercise and hold & relaxation technique on craniovertebral angle (C1~C7) with forward head posture due to using variety bag and using computer in healthy subjects. Design: Randomized Controlled Trial. Methods: 22 subjects were divide into two groups: PSAEx group and H/R group two groups. After exercise, the CVA were measured using C7 and tragus. Collected data were statistically analyzed by SPSS 20.2 Results: There were significant differences pre and post the exercise. Conclusion: PSAEx and H/R technique was effective to correct a abnormal CVA posture. The result of this study may helpful as basic data for orthopedic physical therapy.

• Physical Therapy Korea
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• v.26 no.4
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• pp.1-9
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• 2019

Background: Cervical dysfunction is a common pathomechanical marker in individuals with forward head posture (FHP). To overcome the limitations of the isometric chin-tuck (ICT) exercise, dynamic neuromuscular stabilization (DNS), which emphasizes an entire spinal chain exercise, has recently shown promising clinical results. Objects: Purpose of this study was to compare the immediate effects between ICT and DNS techniques. Methods: 43 young subjects (mean age, $24.0{\pm}5.0$ years) were recruited. Group of subjects with FHP were measured under baseline, ICT, and DNS conditions. Outcome measures included sitting height, longus colli (LC) and sternocleidomastoid (SCM) muscle thickness and LC/SCM thickness ratio. One-way repeated measures ANOVA was used to compare the continuous dependent variables among FHP, ICT, and DNS conditions at p<.016. Results: Both ICT and DNS exercise conditions yielded significantly increased LC muscle thickness, LC/SCM thickness ratio and sitting height than did FHP condition (p<.0001, respectively). Sitting height was significantly greater in DNS exercise than in the ICT exercise (p<.0001). Conclusion: The present results demonstrated that sitting height was greater in the DNS exercise than in the ICT exercise, as well as both corrective postural training exercises were effective on LC/SCM muscle balance ratio when compared with the baseline FHP condition. Therefore, it is considered that DNS exercise can be the recommended exercise for people with FHP.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.117-123
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• 2020

Purpose : VDT (visual display terminal syndrome) can affect individuals who monitor or who work or play using video screens, including those of smartphones. In general, headache symptoms from overuse of these screens can appear due to eye fatigue, muscle pain in the joints of wrists or fingers, and muscle pain in the neck or shoulders. Many studies in the literature have supported standards that seek to prevent these symptoms. The incidence of musculoskeletal diseases caused by the use of smartphones is expected to increase rapidly, particularly among children and young adults, and these diseases are expected to develop into a societal problem. Therefore, in this study we investigate whether tension headaches that develop from smartphone usage can affect forward neck posture, neck pain, and quality of life. Methods : A total of 93 students from University participated in this study. We divided participants into two groups, those with tension headaches (n = 25) and those without (n = 68) and took forward neck measurements. Headaches were classified according to criteria from the International Headache Society and involved bilateral headache position, quality of pressing or tightening pain, mild or moderate pain intensity, and none due to daily physical activity. We surveyed participants using the smartphone addiction diagnosis questionnaire, the Neck Disability Index (NDI), the Headache Impact Test (HIT-6), and the Quality of Life Questionnaire. Results : Although we found no significant differences in tension headaches due to smartphone addiction diagnosis (p = 0.25), SF-36 life quality assessment (p = 0.06), and cranio-vertebral angle (p = 0.07), we found significant differences from the HIT-6 and the NDI (p <.05). Conclusion : Tension headaches are not correlated with smartphone addiction, quality of life, and forward neck angle but do have a correlation with the degree of cervical dysfunction and the effects of the headaches.

• PNF and Movement
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• v.18 no.3
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• pp.403-414
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• 2020

Purpose: This study examined how performing chin tuck exercises in supine, sitting, and standing positions affects changes in the muscle activity of the neck and shoulder. Methods: Seventeen men and three women with forward head posture participated in the study. The subjects performed the chin tuck exercise using a pressure biofeedback unit. After determining the ideal order for performing the chin tuck exercise in supine, sitting, and standing positions through randomized controlled trials, muscle activity was measured in the dominant-side sternocleidomastoid, scalenus anterior, upper trapezius, and levator scapulae. Muscle activity was measured three times in each muscle for each position, and the average of the three measurements was used for analysis. Results: In this study, the chin tuck exercise performed in a supine position reduced muscle activity of the sternocleidomastoid, scalenus anterior, upper trapezius, and levator scapulae significantly more than performing the exercise in either sitting or standing positions (p < 0.05). No significant difference in muscle activity was observed when the exercise was performed in a sitting position versus a standing position (p < 0.05). Conclusion: Performing a chin tuck exercise in a supine position is more effective for stabilizing the neck and shoulder than performing it in a sitting or standing position, as it reduces excessive tension and fatigue in the neck and shoulder.

• Women's Health Nursing
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• v.27 no.4
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• pp.379-387
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• 2021

Purpose: This study aimed to determine the actual state of childbirth in Korean women with natural childbirth and the degree of damage to the perineum during childbirth. Methods: This retrospective study analyzed the medical records of mothers who had natural childbirth at a hospital in Seoul, Korea in 2018. Data from 358 women with cephalic births at greater than 37 gestational weeks were analyzed. To determine natural childbirth characteristics and the degree of damage to the perineum, descriptive statistics were done. The difference in the degree of perineal injury according to obstetric characteristics was analyzed using independent t-test and one-way analysis of variance. Results: The mean age was 33.18±3.68 years, and 49.2% were primiparas, while 39% gave birth with a doula. The degree of perineal damage differed by age (F=9.15, p<.001), parity (t=19.13, p<.001), number of births in multiparity (F=3.68, p=.027), previous vaginal delivery in multiparity (F=3.00, p=.032) and birthing posture (F=7.44, p<.001). Having received therapeutic procedures (t=-4.62, p<.001), specifically fluid administration (t=-2.72, p=.007), oxygen supply (t=-2.76, p=.006) and epidural anesthesia (t=-2.77, p=.006) were statistically significant for perineal damage. There were no differences, however, by gestational period, doula use, water room use in labor, baby head circumference, or birth weight. Conclusion: Study findings suggest that support for older women, primiparas, and those who require therapeutic procedures may help to decrease the possibility of perineal damage during childbirth. As perineal damage was also associated with birthing posture, this should be considered when providing intrapartum nursing care.

• The Korean Journal of Pain
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• v.37 no.2
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• pp.164-177
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• 2024

Background: Neck and jaw pain is common and is associated with jaw functional limitations, postural stability, muscular endurance, and proprioception. This study aimed to investigate the effect of jaw and neck pain on cranio-cervico-mandibular functions and postural stability in patients with temporomandibular joint disorders (TMJDs). Methods: Fifty-two patients with TMJDs were included and assessed using Fonseca's Questionnaire and the Helkimo Clinical Dysfunction Index. An isometric strength test was performed for the TMJ depressor and cervical muscles. The TMJ position sense (TMJPS) test and cervical joint position error test (CJPET) were employed for proprioception. Total sway degree was obtained for the assessment of postural stability. Deep neck flexor endurance (DNFE) was assessed using the craniocervical flexion test. The mandibular function impairment questionnaire (MFIQ) was employed to assess mandibular function, and the craniovertebral angle (CVA) was measured for forward head posture. Results: Jaw and neck pain negatively affected CVA (R² = 0.130), TMJPS (R² = 0.286), DNFE (R² = 0.355), TMJ depressor (R² = 0.145), cervical flexor (R² = 0.144), and extensor (R² = 0.148) muscle strength. Jaw and neck pain also positively affected CJPET for flexion (R² = 0.116) and extension (R² = 0.146), as well as total sway degree (R² = 0.128) and MFIQ (R² = 0.230). Conclusions: Patients with painful TMJDs, could have impaired muscle strength and proprioception of the TMJ and cervical region. The jaw and neck pain could also affect postural stability, and the endurance of deep neck flexors as well as mandibular functions in TMJDs.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.743-760
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• 1997

This study was done to evaluate the correlations between the size, the form of the cranial base, head posture and the horizontal and vertical position of craniofacial structures. For this purpose, 100 cephalometric radiographs were taken from the sample composed of 51 male and 49 female, 12 measurement criteria and 37 reference points were established and digitized, then calculation was performed for the values of measurement variables and the horizontal and vertical position of reference points. The correlations be4ween them were analyzed statistically and mean facial diagrams were constructed and compared with the selected groups which were composed of 10 Samples each as large and small group from the measurement value. The following results were obtained: 1. The angles n-s-ba and n-s-ar as variables for the ion of cranial base correlated highly to the horizontal and vertical position of reference points in the cervical column with statistical significance($0.1\%$ level). 2. The angles n-s-ba and n-s-ar as variables for the form of cranial base correlated to the horizontal position of the reference points in the facial structure with statistical significance($1\%$ level), but not to the vertical position of them($5\%$ level). 3. The length n-s, s-ba, and n-ar as variables for the size of cranial base were correlated th the position of craniofacial structures in various ways, but in general, highly correlated to the horizontal and vertical position of midfacial structures around the teeth and alveolar area. 4. the angle NSL/CVT and NSL/OPT as postural variables tot the inclination of cranial base and cervical column were correlated to the horizontal position of the craniofacial structures with statistical significance($1\%$ level), but not to the vortical position of them($5\%$ level). 5. The angle OPT/HOR and CVT/HOR as postural variables lot the inclination of cranial base and true horizontal line were not correlated to the horizontal and vertical position of the craniofacial structures with statistical significance($5\%$ level). 6. The correlation between the measurement variables and horizontal and vortical positions of the reference poits in soft tissue were shown as similar to the related hard tissue points.