• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.47-52
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• 2021

Purpose: Biofeedback using various ways has helped correct the sitting posture. This study compared the multifidus muscle activity, pelvic and 2nd sacrum tilting angle during typing in nonspecific lower back pain (NCLBP) subjects with and without visual biofeedback. Methods: Thirty subjects with NCLBP were enrolled in this study. An electromyography device was used to measure the multifidus muscle activity. An electromagnetic tracking motion device was used to measure the pelvic and 2nd sacrum tilting angle. The multifidus muscle activity, pelvic, and 2nd sacrum tilting angle were measured before and after typing for 30 minutes in the sitting position. An independent t-test was used to compare the changing values for 30 minutes between the group with and without visual biofeedback. Results: The changing values of the multifidus muscle activity, pelvic, and 2nd sacrum tilting angle were significantly smaller in the group with visual biofeedback than the group without visual biofeedback (p<0.05). Conclusions: In subjects with NCLBP, the visual biofeedback can be recommended to maintain the multifidus muscle activity, pelvic, and 2nd sacrum tilting angle during typing for 30 minutes.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.4
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• pp.425-432
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• 2014

PURPOSE: The purpose of this study was to investigate that the differences in sternocleidomastoid muscle activity, neck rotation angle, neck lateral bending angle and neck lateral bending onset time between conditions with and without visual biofeedback during neck rotation. METHODS: Ten male and four female adults with condition of forward head posture were recruited in this study. Subjects conducted to left and right maximal neck rotation under the conditions with and without visual biofeedback. During neck rotation, kinematic data of neck rotation, neck lateral bending movement, and electromyography activities of bilateral sternocleidomastold muscles were collected. Differences in dependent variables between conditions with and without visual biofeedback were analyzed using paired t-test. RESULTS: There were significant decreases in lateral bending angle, while lateral bending movement onset time was delayed significantly when applying visual biofeedback (p<.05). However, there were no significant differences in the activation of left and right sternocleidomastoid muscles and neck rotation angle between conditions with and without visual biofeedback (p>.05). CONCLUSION: These findings suggest that visual biofeedback may be effective for axial rotation of cervical spine during neck rotation in adults with forward head posture.

• Journal of Fashion Business
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• v.15 no.1
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• pp.80-91
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• 2011

The purpose of this study is to evaluate the differences of visual effects and visual images by variations in shoulder angle and shoulder width of power shoulder jacket. The stimuli are 5 samples: One control group, 2 variations of the angle of shoulder line and 2 variations of the width of shoulder line. The data has been obtained from 87 fashion design majors. The data has been analyzed by Factor Analysis, Anova, Scheffe's Test and the Correlation Analysis. The results of the study are as follows: The visual images by the angle and the width of shoulder line of power shoulder jacket are composed of 4 factors : attention, stiffness and softness, masculinity, and trendiness. Among these factors, attention factor is estimated by the most important factor. The visual effects by the angle and the width of shoulder line of power shoulder jacket are composed of 3 factors : whole silhouette, neck and arm figure, upper body figure. In these factors, the whole silhouette is estimated by the most important factor. The power shoulder jacket with extreme changes in shoulder angle has double images: it looks trendy and classy but also gives an awkward image. In case of changes in shoulder width, the visual evaluation shows big differences with the degree of expansion. The visual evaluation with variation in angle has stronger image and effect than that in width. The power shoulder jacket trend itself is also evaluated that variation in angle reflects the trend better than that in width.

• Physical Therapy Korea
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• v.22 no.4
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• pp.17-26
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• 2015

The purpose of this study was to investigate the effects of visual electromyography (EMG) biofeedback on the EMG activity of the lower trapezius (LT), serratus anterior (SA), and upper trapezius (UT) muscles, the LT/UT and SA/UT EMG activity ratios, and the scapular upward rotation angle during scapular posterior tilting exercise (SPTE). Twenty-four subjects with round-shoulder posture participated in this study. The EMG activities of the LT, SA, and UT were collected during SPTE both without and with visual EMG biofeedback. The scapular upward rotation angle was measured at the baseline, after SPTE without visual EMG biofeedback, and after SPTE with visual EMG biofeedback. The LT, SA, and UT EMG activities, and the LT/UT and SA/UT EMG activity ratios were analyzed by paired t-test. The scapular upward rotation angle was statistically analyzed using one-way repeated analysis of variance. If a significant difference was found, a Bonferroni correction was performed (p=.05/3=.017). The EMG activities of LT and SA significantly increased, and the EMG activity of UT significantly decreased during SPTE with visual EMG biofeedback compared to SPTE without visual EMG biofeedback (p<.05). In addition, the LT/UT and SA/UT EMG activity ratios significantly increased during SPTE with visual EMG biofeedback compared to SPTE without visual EMG biofeedback (p<.05). Significant increases were found in the scapular upward rotation angle after SPTE without and with visual EMG biofeedback compared to baseline (p<.017), and no significant differences were observed in the scapular upward rotation angle between SPTE without and with visual EMG biofeedback. In conclusion, SPTE using visual EMG biofeedback may be an effective method for increasing LT and SA activities while reducing UT activity.

• Honam Mathematical Journal
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• v.37 no.4
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• pp.487-504
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• 2015

For a smooth plane curve, the curvature can be characterized by the rate of change of the angle between the tangent vector and a fixed vector. In this article we prove that the curvature of a space curve can also be given by the rate of change of the locally defined angle between the tangent vector at a point and the nearby point. By using height functions, we introduce turning angle of a space curve and characterize the curvature by the rate of change of the turning angle. The main advantage of the turning angle is that it can be used to characterize the curvature of discrete curves. For this purpose, we introduce a discrete turning angle and a discrete curvature called visual curvature for space curves. We can show that the visual curvature is an approximation of curvature for smooth curves.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.41-47
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• 2013

Background: The purpose of this study is to examine the effects of visual feedback squat exercise on the young adults with Patellofemoral pain syndrome. Methods: The subjects of this study were 22 female and 8 male who were equally and randomly allocated to a visual feedback exercise group (VSEG), an experimental group, and squat exercise group (SEG), a control group. Both did so for 30 minutes three times per week over a six-week period. Using Dartfish, their static Q-angle (SQA) and dynamic Q-angle (DQA) were evaluated. Results: The static Q-angle was significantly reduced in both groups of VSEG and SEG and in the comparison of difference values before and after exercise between groups, VSEG had more significant effect than SEG but in the comparison of the effects of dynamic Q-angle both VSEG and SEG had significant effects and in the comparison of difference values before and after exercise between groups, VSEG had more significant effect than SEG. Conclusion: Visual feedback squat exercise may be applied as a method to correct the lower extremity alignment with PFPS.

• The Journal of Korean Physical Therapy
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• v.30 no.2
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• pp.47-53
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• 2018

Purpose: To find the effect of visual feedback of head angle with using a mobile posture-aware system on craniocervical angle and neck and shoulder muscles fatigue for preventing or decreasing the forward head posture. Methods: Twenty-four healthy young adults in Chungbuk to participate in this study. The subjects started to watch a movie clip for 10 minutes with visual feedback in $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ of head angles. During the task, surface electromyography (EMG) was used to collect data from the upper trapezius (UT), sternocleidomasetoid muscle (SCM), cervical erecter spinae (CES) during watching the smartphone. Craniocervical angles were measured using a sagittal-view photograph of the subject in a sitting posture. A one-way repeated analysis of variance with a significant level of 0.05 used for statistical analysis. Results: Craniocervical angle with $0^{\circ}$ visual feedback was significantly greater than $30^{\circ}$ and $60^{\circ}$. Craniocervical angle with $30^{\circ}$ visual feedback was significantly greater than $60^{\circ}$. In addition, MDF of UT muscles in $0^{\circ}$ and $30^{\circ}$ of visual feedback was significantly greater than $60^{\circ}$. Conclusion: We concluded that $0^{\circ}$ visual feedback of head angle with using a mobile posture-aware system would be beneficial to prevent or decrease forward head posture during watching a smartphone. We also could recommend using of $30^{\circ}$ visual feedback in case of caring UT muscle fatigue primarily.

• KIEAE Journal
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• v.9 no.2
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• pp.81-90
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• 2009

Relating to grasping sequential landscape characteristics in consideration of the behavioral characteristics of the subject experiencing visual perception, this study was made on the subject of main walking line section for visitors of three treasures of Buddhist temples. Especially, as a method of obtaining data for grasping sequential visual perception landscape, the researcher employed [momentum sequential viewpoint setup] according to [the interval of pointers arbitrarily] and fisheye-lens-camera photography using the obtained omni-directional angle visual perception information. As a result, in terms of viewpoint selection, factors like approach road form, change in circulation axis, change in the ground surface level, appearance of objects, etc. were verified to make effect, and among these, approach road form and circulation axis change turned out to be the greatest influences. In addition, as a result of reviewing the effectiveness via the subjects, for the sake of qualitative evaluation of landscape components using the VR picture image obtained in the process of acquiring omni-directional angle visual perception information, a positive result over certain values was earned in terms of panoramic vision, scene reproduction, three-dimensional perspective, etc. This convinces us of the possibility to activate the qualitative evaluation of omni-directional angle picture information and the study of landscape through it henceforth.

• The Journal of Korean Physical Therapy
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• v.33 no.3
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• pp.162-167
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• 2021

Purpose: A hyperextended knee is described as knee pain associated with an impaired knee extensor mechanism. Additionally, a hyperextended knee may involve reduced position sense of the knee joint that decreases the individual's ability to control end-range knee extension movement. The purpose of this study was to investigate the effects of visual biofeedback information for plantar pressure distribution on knee joint angle and lower extremity muscle activities in participants with hyperextended knees. Methods: Twenty-three participants with hyperextended knees were recruited for the study. Surface electromyography signals were recorded for the biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior muscle activities. The plantar pressure distribution was displayed and measured using a pressure distribution measuring plate. Knee joint angle kinematic parameters were recorded using a motion analysis system. The visual biofeedback condition was the point at which the difference between the forefoot and backfoot plantar foot pressure on the monitor was minimized. The Wilcoxon signed-rank test was used to determine the significance between the visual biofeedback condition and the preferred condition. Results: The knee joint angle was significantly decreased in the visual biofeedback condition compared to that in the preferred condition (p<0.05). The rectus femoris and gastrocnemius muscle activities were significantly different between the visual biofeedback and preferred conditions (p<0.05). Conclusion: The results of this study showed that visual biofeedback of information about plantar pressure distribution is effective for correcting hyperextended knees.

• The Journal of Korean Physical Therapy
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• v.34 no.4
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• pp.155-160
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• 2022

Purpose: This study was to identify the effect of cervical stabilization exercise with visual feedback on the craniovertebral angle and foot pressure in subjects with forward head posture. Methods: Thirty healthy adults were recruited in the study. Participants were randomly assigned to the stabilization exercise with visual feedback (SE-VF) group (n=15) or stabilization exercise (SE) group (n=15). The SE-VF group performed cervical stabilization exercise while sitting on a chair without a backrest and checking their side profile in real time a monitor 3m away. The SE group performed the same cervical stabilization exercise as the SE-VF group accompanied by without visual feedback. Craniovertebral angle (CVA) was measured to quantify forward head posture, and the foot pressure of the subjects were evaluated. Results: The foot pressure showed statistically significant differences pre and post in both midfoot and left metatarsal only in SE-VF group (p<0.05). Conclusion: These findings of this study showed that the cervical stabilization exercise with visual feedback was effective for the foot pressure of subjects. In addition, based on the results of this study, it is suggested that visual feedback will be effective in cervical stabilization exercise.