• PNF and Movement
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• v.21 no.2
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• pp.185-192
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• 2023

Purpose: This study aimed to confirm the effectiveness of the diaphragm stretching technique as a treatment method for low back pain by evaluating maximum inspiratory pressure, maximum expiratory pressure, and changes in back mobility in patients with low back pain. Methods: Thirty-four patients with low back pain were randomly divided into two groups: an experimental group and a control group. The diaphragm stretching technique was conducted in the experimental group, and the placebo intervention was conducted in the control group. The diaphragm stretching technique was conducted once, maintaining tension for 7 min. The placebo intervention was conducted in the same position as the diaphragm stretching technique, but with only light contact maintained without pressure. Maximum inspiratory pressure, maximum expiratory pressure, and back mobility were measured before and after the intervention, and the changes were compared and analyzed. A paired sample t-test was used to compare measurements within the group before and after the intervention. An independent t-test was used to compare the experimental and control groups. Statistical significance (α) was set at 0.05. Results: In the experimental group, maximum inspiratory pressure, maximum expiratory pressure, and back mobility increased significantly after the intervention (p < 0.05). However, there was no significant difference in the changes in all areas of the control (p > 0.05). As a result of comparative analysis of changes before and after the intervention, there were significant differences in maximum inspiratory pressure, maximum expiratory pressure, and back mobility only in the experimental group (p < 0.05). Conclusion: The diaphragm stretching technique improved maximum inspiratory pressure, maximum expiratory pressure, and back mobility compared to the placebo intervention. Therefore, the diaphragm stretching technique can be recommended as a physical therapy intervention to improve pain in patients with LBP.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.4
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• pp.615-621
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• 2010

Purpose : The purpose of this study was to compare chronic LBP patients and asymptomatic subjects on measures of multifidus size (cross-sectional area;CSA, thickness) and symmetry (proportional difference of relatively larger side to smaller side). Methods : Data were obtained from 12 asymptomatic subjects without a prior history of LBP (8 females, 4 males), and a retrospective audit was undertaken of records from 12 chronic low back pain patients (8 females, 4 males). CSA and Thickness of the lumbar multifidus muscles was measured from axial T1-weighted magnetic resonance images(MRI). Results : The results of the analysis showed that chronic LBP patients had significantly smaller multifidus CSA and thickness than asymptomatic subjects at L4-5 vertebral levels(p<.05). The asymmetry between sides was seen at L4- L5 vertebral level in patients with chronic low back pain presentations(p<.05). Conclusions : MRI provided a quantitative measure of change between asymptomatic subjects and chronic low back pain patients of multifidus muscle. MRI identified significant differences in cross-sectional area and thickness and helps to evaluate clinically and plan the treatment modalities of LBP.

• Physical Therapy Korea
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• v.22 no.3
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• pp.61-70
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• 2015

To develop an effective and efficient measurement system for tracking changes of functional status across two measures, it is essential to integrate information and communicate scores across two measures. The lack of communication between two measures leads to score incompatibility. A potential solution would be the development of a crosswalk table between those measures. Prior to creating a crosswalk table, selecting common items between two measures is critical. By using the Oswestry low back pain disability questionnaire (Oswestry) and a short form measuring disability resulting from low back pain, item level statistics as well as differential item functioning (DIF) using the Rasch measurement were investigated. Eighty-two participants with known group validity were recruited. Based on the application of the Rasch measurement model, item difficulties across the two measures were logically and hierarchically ordered. Ceiling effects for both measures were detected, which were not be able to be effectively measured with the two measures. The DIF analysis across the two measures confirmed that five paired items were found to have DIF and five common items were selected for common items. Although five paired items function differently across the Oswestry and the short form, all items of both measures were well targeted study participants. The common items selected by the Rasch measurement model may be effective when creating a crosswalk table between the Oswestry and the short form.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.7
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• pp.344-351
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• 2006

The fatigue of back muscle in the repetitive lifting motion was studied using multiple parameters(FFT_MDF, RMS, 2C, NT) in this study. Recent developments in the time-frequency analysis procedures to compute the IMDF(instantaneous median frequency) were utilized to overcome the nonstationarity of EMG signal using Cohen-Posch distribution. But the above method has a lot of computation time because of its complexity. So, in this study, FFT_MDF(median frequency estimation based on FFT) algorithm was used for median frequency estimation of back muscle EMG signal during muscle work in uniform velocity portion of lumbar movement. The analysis period of EMG signal was determined by using the run test and lumbar movement angle in dynamic task, such as lifting. Results showed that FFT_MDF algorithm is well suited for the estimation of back muscle fatigue from the view point of computation time. The negative slope of a regression line fitted to the median frequency values of back muscle EMG signal was taken as an indication of muscle fatigue. The slope of muscle fatigueness with FFT_MDF method shows the similarity of 77.8% comparing with CP_MDF(median frequency estimation based on Cohen Posch distribution) method.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.79-86
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• 2015

This study explored the vowel effect on acoustic perturbation measures in voice quality analysis. For this study, the perturbation parameters (%jitter, %shimmer) and noise parameter (SNR) were measured with 7 Korean vowels (/a/, /ɛ/, /i/, /o/, /u/, /ɯ/, /ʌ/) using CSpeech with 50 Korean normal young adults (24 males and 26 females). A significant vowel effect was found only in %shimmer and in particular, low-back /a/vowel was significantly different from other vowels in %shimmer. The least perturbation and noise were exhibited on high-back /ɯ/ and /o/ vowel, respectively. Based on tongue height, a significant higher %shimmer was demonstrated on low vowels than high vowels. In addition, back vowels in tongue advancement and rounded vowels in lip rounding showed significantly less perturbation and noise. The least variability of perturbation and noise within individuals was demonstrated on the vowel /i/ in three repeated measures. However, there was no significant difference among 3 token measures in single session among vowels tested except the vowel /o/. Consequently, the vowel /a/ commonly used in acoustic perturbation measures exhibited higher perturbation and noise whereas higher stability and less variability were demonstrated on the high-back vowel /u/. These results suggested that the Korean high-back vowel /u/ can be more appropriate and reliable for perturbation acoustic measures.

• Physical Therapy Korea
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• v.4 no.1
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• pp.78-86
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• 1997

Back muscles play an important role in protecting the spine. Epidemiological studies have shown that loads imposed on the human spine during daily living play a significant role in the onset of low back pain. No previous study has attempted to correlate the response of the trunk musculature with the type of external load. The purpose of this study was to use surface electromyography (EMG) to quantify the relative demands placed on the back muscles while lifting loads in one hand. Forty asymptomatic, twenty year-old subjects stood while lifting loads of 10% of body weight(BW) unilaterally. All EMG data were normalized to a percentage of the EMG voltage produced during no-load standing(%EMG). Our major analysis involved a paired t-test for repeated measures. Of particular note was the fact that the ipsilateral 10% of BW condition produced statistically less % EMG change than did the contralateral 10% of the condition.

• Korean Journal of Applied Biomechanics
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• v.34 no.1
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• pp.9-17
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• 2024

Objective: The purpose of this study is to apply 8-week velocity-based training to domestic professional athletes and the kinematic and kinetic analysis of the 1-RM improvement of back squat and power clean, which can represent strength-power ability, to verify the effectiveness of velocity-based training in Korea and to establish a basic basis. Method: The subjects who participated in this study were 10 professional athletes from K University (age: 21.40 ± 0.97 yrs., height: 179.90 ± 3.54 cm., body mass: 71.298 ± 2.98 kg). All subjects performed back squat and power clean 1-RM before and after 8-weeks of velocity-based training. A 3-dimensional motion analysis with 8 infrared cameras and 4 channels of EMG was performed in this study. A paired t-test was used for statistical verification. The significant level was set at α=.05. Results: Both Back squat and Power Clean 1-RM showed statistically significant increases (p<.05). In the case of back squat, there was no statistically significant difference in both kinematic and kinetic variables (p>.05). In the case of Power Clean, only the quadriceps of Phase 1 showed a statistically significant decrease (p<.05). Conclusion: Domestic professional athletes can improve their strength-power ability through velocity-based training, and such training for at least 8-weeks is considered a way to improve their performance.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.2
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• pp.85-94
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• 2013

Objectives : This study aims to contribute to developing new pattern identification based on searches regarding pattern identification of low back pain, which is used in thesis both in Korea and China. Methods : First of all, we searched thesis concerning pattern identification of low back pain from RISS, OASIS, Korean traditional knowledge portal, CNKI. Results : 1. There were overall 34 thesis, consist of 18 Korean thesis(13 clinical papers and 5 analytical papers) and 9 Chinese thesis(7 clinical papers and 9 analytical papers). 2. 10 of 11 Korean thesis used more than 9 patterns for pattern identification, 9 of 14 Chinese thesis used less than 4 patterns for pattern identification of low back pain. 3. Patterns, which were repeatedly used in Korea, were 腎虛腰痛(Kidney deficiency low back pain), 濕熱腰痛(Dampness-heat low back pain), 寒濕腰痛(Cold-dampness low back pain), 痰飮腰痛(Phlegm-fluid retention low back pain), 風腰痛(Wind low back pain), 食積腰痛(Food accumulation low back pain), 濕腰痛(Dampness low back pain), 挫閃腰痛(Sprain low back pain), 瘀血腰痛(Static blood low back pain), 氣腰痛(Qi low back pain). 4. Patterns, which were repeatedly used in China, were 腎虛腰痛(Kidney deficiency low back pain), 濕熱腰痛(Dampness-heat low back pain), 寒濕腰痛(Cold-dampness low back pain), 氣滯血瘀腰痛(Blood stasis due to qi stagnation low back pain). Conclusions : Based on these results, it is considered that an advanced type of pattern identification of low back pain should be made or existing type needs to be practically and objectively improved.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.285-299
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• 2004

The purpose of this study is to identify female 500m sprint start motion by the center of gravity position in short track speed skating. The center of gravity position ratio was divided into three type(type A front : 80%-back : 20%, type B front : 70%-back 30%, type C front: 50%-back : 50%). Three video cameras were used for 3D motion analysis with DLT method and the results were as follows: The elapsed time in starting motion was appeared that type B was the shortest and type A was the longest. It was appear that the stroke length of type A was longer than that type B and C during starting phase. This result was similar to displacement of center of gravity. It was appeared that skill type of center of gravity position ratio type B' ankle and knee joint angle were lower than that of type A and C. Observing these results it was conclusion that skill type B of center of gravity position ratio was more faster than that of type A and C. But it is important that these skill type needed to verifying more subjects.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1219-1226
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• 2014

This paper introduces a hardware simulator for the LVRT operation analysis of the grid-tied PMSG wind power system with a power dissipation circuit. The power dissipation circuit, which is composed of chopper and resistor, suppresses the sudden increase of DC-link voltage in the back-to-back converter of the grid-tied PMSG wind power system. The LVRT operation was first analyzed using computer simulations with PSCAD/EMTDC. A wind power simulator including the power dissipation circuit and the fault simulator composed of variac and IGBT were built to analyze the LVRT operation. Various experiments were conducted to verify the effectiveness of the power dissipation circuit for the LVRT operation. The developed hardware simulator can be extensively utilized for the analysis of various LVRT operations of the grid-tied wind power system.