• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.386-392
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• 2013

Purpose: This study aimed to verify the impact of the time that the sitting posture is maintained on changes in muscle performance and head alignment. Methods: The subjects of this study were healthy adults aged between 20 and 30 years. Ninety-three subjects participated in this study (male: 57, female: 36). The subjects were divided into a one-hour group, a two-hour group, and a three-hour group. All the subjects adjusted the height of their chair to a comfortable position and then seat for one, two, or over three hours. Both prior to and after the experiment, the muscle performance (muscle strength, endurance, and flexibility) of the subjects was measured. Results: In the 2-hours and 3-hour group, muscle strength, flexibility and endurance reduced significantly before and after the study, and the head alignment significantly changed. Conclusion: Thease findings showed that sitting continuously for longer than two hours decreases muscle strength, endurance, and flexibility. A flexed posture affects the muscle performance of the lumbar region and may result in problematic postures, such as a forward head position.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.3
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• pp.35-39
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• 2016

PURPOSE: The purpose of this study was to examine changes in the neck flexion angle according to posture while using a smartphone and the duration of smartphone usage. METHODS: The subjects in this study were 16 healthy young students in their 20s. The subjects wore a cervical range of motion instrument. They were instructed to use a smartphone while standing, sitting on a chair, and sitting on the floor. In all postures, they could use the smartphone and use their arms freely while keeping their back connected to the wall or the back of the chair. When sitting on the floor, they assumed a cross-legged position. The neck flexion angle was measured at zero, three, six, and nine minutes for each posture. RESULTS: Neck flexion is affected by the posture while using a smartphone (p<.05). Neck flexion in the standing position is larger than that in the sitting on the floor position. Neck flexion was affected by smartphone usage duration (p<.05). In general, as usage time increases, the neck flexion angle increases as well. CONCLUSION: This study suggests that using smartphone in the standing position and for a short period of time is a method to reduce the neck flexion angle.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.341-348
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• 2012

The purpose of this study was to compare the muscle activities of the thoracic extensor(TE) and lumbar extensor(LE) during trunk lift (TL) exercise according to exercise position. Seventeen healthy subjects with no medial history of back pain were recruited for this study. Subjects performed the TL exercise in prone, quadruped and heel-sitting positions. The activities of the TE and LE were measured using surface electromyography during TL exercise in each exercise position. A one-way repeated-measures analysis of variance (ANOVA) was used to compare the normalized muscle activities of the TE and LE and the TE/LE ratio. The results showed that there was not significant effect of exercise position on the muscle activities of TE(p>.05). However, there was significant effect of exercise position on the muscle activities of LE and the TE/LE ratio(p>.05). Post hoc pair-wise comparisons with Bonferroni correction showed that both muscle activities of LE and TE/LE ratio in prone position were significantly different in those in heel-sitting and quadruped positions, during TL exercise, respectively. The TE/LE ratio was the greatest for TL exercise in heel-sitting position. Therefore, for selective activation of the TE muscle, we recommend performing the TL exercise in heel-sitting or quadruped position.

• Journal of Korean Physical Therapy Science
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• v.6 no.1
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• pp.915-921
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• 1999

The purpose of this study was to determine the effect of testing posture and shoulder position on grip strength. The subjects were one hundred volunteers of Shinsung College (50 males and 50 females), ages from 20 to 27 years(mean age of 22.1 years). This study was carried out from september 7 to setember 10, 1998. The data were analyzed by mean and deviation, unpaired t-test, paired t-test, one way ANOVA and correlation. These results were obtained as follows; 1. Comparison on grip strength by left and right hand, there was a significant difference in standing and sitting position (p<0.05). 2. Comparison on grip strength between male and female, there was a significant difference in standing and sitting position (p<0.05). 3. One-way ANOVA on grip strength according to shoulder joint angle, there was a no significant difference in standing and sitting position (p>0.05). 4. Correlation on grip strength by sitting verus standing, there was a very significantly difference (p<0.01).

• Journal of the Korean Home Economics Association
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• v.18 no.4
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• pp.31-39
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• 1980

The basic pattern of skirt should be functional in addition to be fit the body. The author paid special attention to the expansion and contraction of the shell which were made the lower trunk and thigh caused by sitting motions. The replicas of the shell were taken by using a gypsum method on 1 female under 4 standardized motions; standing motion, (basic motion), sitting on the chair with flextion 90' at the hip and the knee joints sitting with dropping knees, and sitting with benting legs side wards. Those replicas obtained were developed to the patterns and changes in shape and area of those were measured. Typical displacement and transformation of the shell surface patterns were showed geographycally fig 5-1 to 5-4. mean values of expansion and constriction were obtained by measuring the shell surface on 60 female under the 4 motions. the mean values of it were showed numerically in Table 1-1 to 1-3. The following results were obtained; 1. Vertical constriction of front of the shell were observed near sulcus in guinalis, and vertical extension were near the knees. Horizontal extension were observed near the thighs and the knees. 2. Vertical constrictions of the back of the shell were observed near the knees. It seemed to be influnced the flexion angles of knee points. vertical extension were near gluteus and thighs. Horizontal constriction were small, and horizonlal extension were near gluteus. 3. The high rates of constriction and extension were found near sulcus in guinalis, glutes, and knees. 4. The rates of constriction and extension on the waist line were very low. 5. The highest values of constriction and extension were found in hip and knees.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.285-291
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• 2015

In this paper, we propose a classification algorithm for postures of sitting person by using IMU(inertial measurement unit). This algorithm uses PCA(principle component analysis) for decreasing the number of feature vectors to three and SVM(support vector machine) with RBF(radial basis function) kernel for classifying posture types. In order to collect the data, we designed neckband-shaped earphones with IMU, and applied it to three subjects who are healthy adults. Subjects were experimented three sitting postures, which are neutral posture, smartphoning, and writing. As the result, our PCA-SVM algorithm showed 95% confidence while the dimension of the feature vectors was reduced to 25%.

• Journal of Korean Academy of Nursing
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• v.15 no.2
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• pp.25-33
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• 1985

This study intended to investigate the volume of respiration according to the postoperative time and positions among the upper abdominal surgery patients. Tidal volume and vital capacity were measured in three positions-supine, left lateral and sitting position-at preoperatively, 12 hours postoperatively and 36 hours postoperatively. Thirteen male and seven female patients who were admitted for elective abdominal surgery under general anesthesia were the subjects of the study. Those patients with cardiopulmonary problems, obesity and smoking habit were excluded from the study. The study was conducted from March 15 to June 30, 1985 in Seoul National University Hospital. Tidal volume and vital capacity were measured by Wright spirometer in various positions at preoperatively, 12 hours postoperatively and 36 hours postoperatively. The results were as following: 1) Vital capacity was significantly decreased at 12 hours preperatively and 36 hours postoperatively than preoperatively. Vital capacity was not significantly different in Various positions, but sitting position revealed better than left lateral and supine position. Tidal volume was not significantly different in each position. 2) Male patients showed significantly higher than female patients in tidal volume and vital capacity. Vital Capacity was not significantly different by sex in each position, but vital capacity was higher in sitting position than in lateral and supire position. 3) There was not significantly different in tidal volume and vital capacity according to the type of incision and positions, vital capacity was higher in sitting positionthan in left lateral and supine position.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.2
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• pp.17-23
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• 2018

Purpose : The purpose of this study was to investigate whether the respiratory cycle and posture can modulate the autonomic nervous system. Methods : Thirty-two healthy men and women, aged 20-30 years, were enrolled in this study. We conducted 2-second and 6-second respiratory cycle with the subjects in standing, sitting, and supine positions, respectively. Their heart rate variability was measured in each position for both cycle lengths. Results : The low frequency/high frequency (LF/HF) ratio is derived from heart rate variability. In the 2-second respiratory cycles, the LF/HF ratios were highest in standing, sitting, and supine position in descending order. There was a significant difference in heart rate between standing and sitting positions (P<.005). In addition, there was a significant difference in heart rate between standing and supine position (P<.000). In the 6-second respiratory cycles, the LF/HF ratios were again highest in a standing, sitting, and supine position in descending order. However, posture was not found to make a significant difference in this case. Conclusion : Respiratory cycle and posture effectively modulated the autonomic nervous system. Further studies of the clinical application of these results should be conducted.

• The Journal of Korean Physical Therapy
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• v.16 no.4
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• pp.115-128
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• 2004

The purpose of this study was to evaluate respiratory functions in relation to the gross motor functions(total value of GMFM), the difference of chest girth, and the changing position in spastic children. The respiratory functions(FVC, FEV1, $FEV1\%$, and PEF) were measured in the supine, the $45^{\circ}$semi-sitting, and the $45^{\circ}$sitting in 9 subjects. In the supine position, the mean difference of chest girth was $1.56{\pm}0.80cm$, the total value of GMFM was $45.41{\pm}17.79\%$. In the supine position, there was significant positive relationship in FVC-FEV1, FVC-PEF, and FEV1-PEF, but there was no significant relationship in GMFM and all respiratory functions. In the $45^{\circ}$semi-sitting, there was significant positive relationship in GMFM-FVC, FVC-FEV1, FVC-PEF, FEV1-PEF, and $FEV1\%-PEF$. In the $90^{\circ}$sitting, there was significant positive relationship in GMFM-FEV1, $GMFM-FEV1\%$, FVC-FEV1, FVC-PEF, and FEV1-PEF. In results of measured respiratory functions according to the postures, the supine position had highest value in all respiratory functions, but there were no significant (p<0.05).

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.31-38
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• 2009

Purpose: This study was examined the effect of training using a Virtual Reality System on the sitting balance and Activities of Daily Living for patients with a spinal cord injury. Methods: The subjects were divided into an experimental (6 persons) and control group (5 persons). The experimental group trained the 5 programs, three times per week for 6 weeks using the Virtual Reality System and five days for week using conventional physical therapy. The control group trained five days for a week using conventional physical therapy. Results: The difference in the mean Spinal Cord Independence Measurement (SCIM) score in the experimental and control groups was increased to 8.33 and 6.60 (p=0.79), respectively. The difference in the mean functional reaching test in experimental and control group increased to 4.21 and 1.09 (p=0.25), respectively. The difference in the mean sitting time in experimental and control group increased to 41.05 and 10.33 (p=0.66), respectively. There was a difference in the mean of all variances but these differences were not statistically significant. Conclusion: These results suggest that training using the Virtual Reality System increased the SCIM, functional reaching test and sitting time in people with a spinal cord injury.