• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.124-131
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• 2017

This paper present a novel approach to control the lower body power assistive exoskeleton system of a HEXAR-CR35 aimed at improving a muscular strength. More specifically the control of based on the human intention is crucial of importance to ensure intuitive and dexterous motion with the human. In this contribution, we proposed the detection algorithm of the human intention using the MCRS which are developed to measure the contraction of the muscle with variation of the circumference. The proposed algorithm provides a joint motion of exoskeleton corresponding the relate muscles. The main advantages of the algorithm are its simplicity, computational efficiency to control one joint of the HEXAR-CR35 which are consisted knee-active type exoskeleton (the other joints are consisted with the passive or quasi-passive joints that can be arranged by analyzing of the human joint functions). As a consequence, the motion of exoskeleton is generated according to the gait phase: swing and stance phase which are determined by the foot insole sensors. The experimental evaluation of the proposed algorithm is achieved in walking with the exoskeleton while carrying the external mass in the back side.

• The Journal of Korean Physical Therapy
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• v.21 no.4
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• pp.51-56
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• 2009

Purpose: This study examined the difference in the static balance ability according to the visual cues and postural tasks in normal subjects. Methods: Thirty participants (12 male, 18 female; mean age $24.63\pm1.43$ years) stood barefoot on a force platform in a one-legged stance, tandem Romberg stance and tandem Romberg with neck extension stance with a visual cue open and closes. The static balance was assessed by the center of pressure (CoP), surface electromyography root mean square (RMS) of the leg muscles according to the stance position. Results: In the CoP tests, the difference in the unit path length and circumference area was affected by the visual cue according to the stance posture (p<0.01). In the RMS tests, the difference in the tibialis anterior and medial gastrocnemius muscle was affected by visual cue in accordance with the stance posture (p<0.01). Conclusion: The visual cue and postural task affect the balance ability in normal subjects. Therefore, this study provides clinical evidence that the balance and postural control can be improved. Therapeutic intervention, such as an obstacle course, and a lower leg muscle performance program with a change in the base of support can affect the balance and postural control.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.21-30
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• 2023

PURPOSE: The present study evaluated the occurrence, somatometric, biochemical, and behavioral characteristics of young Korean sarcopenic males aged between 30 to 39 years. METHODS: The study involved a total of 1,546 participants. These individuals were divided into two distinct groups based on their skeletal muscle mass index. Of these, 49 participants were categorized into the sarcopenia group, while the remaining 1,497 individuals were placed in the normal group. The researchers analyzed the occurrence of sarcopenia, somatometric, biochemical, and behavioral characteristics such as height, weight, body mass index (BMI), waist circumference (WC), skeletal muscle mass index, fasting glucose (FG), triglyceride and total cholesterol (TC) levels, systolic (SBP) and diastolic blood pressure (DBP), and the drinking and smoking status. A complex sampling data analysis was performed. RESULTS: The weighted occurrence of sarcopenia was found to be 3.24%, (95% confidence interval (CI) of 2.39% to 4.36%). The somatometric contributing factors were height, BMI, and WC (p < .05). Triglyceride and TC levels exhibited statistically significant differences in the biochemical variables (p < .05). The behavioral characteristics, including the drinking and smoking status, had no statistical significance (p > .05). CONCLUSION: This study identified specific occurrences of sarcopenia and contributing factors in young Korean men.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.57-66
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• 2023

PURPOSE: This research investigated clinical hazardous components and analyzed the proportion of sarcopenia among young Korean women. METHODS: The cross-sectional study included 1,236 women aged 20 to 29 years, categorized into two groups according to their skeletal muscle mass index (SMI). Of these, 20 participants were placed in the sarcopenia group, while 1,216 were included in the normal group. The analysis involved hazardous components including body dimensions, clinical indicators, and behavioral trait variables: height, weight, body mass index, waist circumference, skeletal muscle mass index, systolic and diastolic blood pressure, blood laboratory tests assessing fasting glucose, triglycerides, total cholesterol, as well as smoking habits and alcohol consumption. Complex sampling analysis was used to analyze the proportion and hazardous components of sarcopenia. RESULTS: The proportion of sarcopenia was at 1.76% (95% of CI: 1.08-2.83). Anthropometric measurements, such as height, BMI, and WC, exhibited significant differences between the groups (p < .05). However, there was no significant difference in weight (p > .05) between the two groups. Among the clinical indicators, SBP, DBP, FBG, serum triglycerides, and total TC found to be significant hazardous components for sarcopenia within both groups (p < .05). Smoking status as a behavioral trait was significant as well (p < .05), unlike alcohol consumption (p > .05). CONCLUSION: This study discerned both the proportion of sarcopenia and the hazardous components associated with it among community-dwelling women of a young age.

• Physical Therapy Korea
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• v.25 no.1
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• pp.1-11
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• 2018

Background: The continuous co-contraction of the trunk muscles through trunk stabilization exercises is important to patients with lumbar spinal stenosis (LSS). However, intentional abdominal muscle contraction (IAMC) for trunk stabilization has been used only for specific training in the treatment room. Objects: The purpose of this study was to provide feedback to adults with LSS to enable IAMC during activities of daily living (ADLs). Methods: The participants with spinal stenosis were divided into an experimental group of 15 adults and a control group of 16 adults. Electromyographic signals were measured while the subjects kept their both hands held up at $90^{\circ}$. The measured muscles were the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES). Pelvic tilt was measured using a digital pelvic inclinometer. The degree of pain was measured using the visual analogue scale (VAS) and functional capacity was measured using the Korean version of the Oswestry disability index (KODI). Results: While the experimental group showed statistically significantly higher activities in the RA, EO, and IO after the intervention compared with the control group. Pelvic tilt was significantly decreased only in the experimental group. Both the experimental and control groups exhibited statistically significant declines in the VAS and KODI (p<.01). In terms of the levels of changes, the experimental group exhibited a statistically significant larger decline only in the VAS and the pelvic tilt when compared with the control group (p<.05). Conclusions: The subjects could stabilize their trunks, and relieve their pain and dysfunctions and reduce pelvic tilt by learning abdominal muscle contraction during ADLs. The combination of therapeutic exercises and IAMC may have greater effects on patients with LSS.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.363-369
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• 2018

The purpose of this study was to perform exercise program for patients with borderline hypertension and hypertension. And the change of the metabolic syndrome index. This study was performed for 15 weeks on borderline hypertension, hypertension patients. 28 subjects participated in the exercise program for 40 minutes, three times a week for 15 weeks. The following conclusions were obtained. First, there was a significant correlation between the prevalence of metabolic syndrome before and after the exercise program. Second, there were significant differences in body weight, muscle mass, fat mass, BMI, waist circumference, diastolic blood pressure, and blood sugar before and after 15 weeks of exercise program. This can lead to improved metabolic syndrome indicators in hypertensive patients with a muscle extension exercise program.

• Nutrition Research and Practice
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• v.15 no.1
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• pp.95-105
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• 2021

BACKGROUND/OBJECTIVES: The measurement of body composition, including muscle and fat mass, remains challenging in large epidemiological studies due to time constraint and cost when using accurate modalities. Therefore, this study aimed to develop and validate prediction equations according to sex to measure lean body mass (LBM), appendicular skeletal muscle mass (ASM), and body fat mass (BFM) using anthropometric measurement, serum creatinine level, and lifestyle factors as independent variables and dual-energy X-ray absorptiometry as the reference method. SUBJECTS/METHODS: A sample of the Korean general adult population (men: 7,599; women: 10,009) from the Korean National Health and Nutrition Examination Survey 2008-2011 was included in this study. The participants were divided into the derivation and validation groups via a random number generator (with a ratio of 70:30). The prediction equations were developed using a series of multivariable linear regressions and validated using the Bland-Altman plot and intraclass correlation coefficient (ICC). RESULTS: The initial and practical equations that included age, height, weight, and waist circumference had a different predictive ability for LBM (men: R2 = 0.85, standard error of estimate [SEE] = 2.7 kg; women: R2 = 0.78, SEE = 2.2 kg), ASM (men: R2 = 0.81, SEE = 1.6 kg; women: R2 = 0.71, SEE = 1.2 kg), and BFM (men: R2 = 0.74, SEE = 2.7 kg; women: R2 = 0.83, SEE = 2.2 kg) according to sex. Compared with the first prediction equation, the addition of other factors, including serum creatinine level, physical activity, smoking status, and alcohol use, resulted in an R2 that is higher by 0.01 and SEE that is lower by 0.1. CONCLUSIONS: All equations had low bias, moderate agreement based on the Bland-Altman plot, and high ICC, and this result showed that these equations can be further applied to other epidemiologic studies.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.31-37
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• 2023

PURPOSE: This study aimed to investigate the relationship between being underweight and respiratory function indicators such as pulmonary function, respiratory muscle strength, and diaphragm thickness in normal adults without lung disease. METHODS: The participants in this experiment were thirty young adults. To compare the respiratory function between the underweight and normal weight individuals, 15 participants were selected from each of the underweight and normal weight groups based on body mass index. Respiratory function tests were conducted through pulmonary function tests and respiratory muscle strength tests. Diaphragm thickness was measure with ultrasonography, and physical characteristics were obtained from grip strength and waist circumference. An independent t-test was used to compare the averages of the parameters measured in the two groups. RESULTS: In the respiratory function tests between the two groups, statistically significant differences (p < .05) emerged in the ratio of the predicted forced vital capacity (%FVC), the ratio of the predicted forced expiratory volume in one second (%FEV1), maximal expiratory pressure (MEP), and diaphragm thickness at the functional residual capacity (FRC). There was no statistically significant difference in the forced vital capacity, forced expiratory volume in one second, maximal inspiratory pressure, diaphragm thickness at the total lung capacity, and thickening ratio (p > .05). CONCLUSION: Decreases in some variables of respiratory function, such as the %FVC, %FEV1, MEP, and diaphragm thickness at the FRC were observed in underweight subjects. However, it is difficult to determine whether it affected the overall respiratory function. Future studies are needed to clearly identify the relationship between being underweight and respiratory function.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.210-220
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• 2023

Recently, smart wearable products, including electromyography (EMG) measurement devices and clothing, have been developed to monitor users' exercise levels, muscle activation, and muscle balance more effectively during fitness activities. However, technical and socioeconomic barriers, such as flexibility and durability, still pose challenges in terms of comfort, ease of wear, and wearability of smart clothing, which includes devices and circuits. To address these issues, this study developed a wearable EMG device integrated with clothing to collect valid EMG signals from desired muscles while maintaining comfort, functionality, and ease of wear. After deriving a combined structure that could stably position the wearable device within the clothing, a prototype was manufactured and evaluated for fit, compression, comfort, and exercise comfort test by ten participants (height = 176.2 cm, weight = 76.4 kg, chest circumference = 101.2 cm). The study found that the prototype had smaller circumferences around the chest, waist, and abdomen compared to commercial products, resulting in lower ratings for wearing comfort and ease of wear. However, the prototype received high ratings for fitting, pressure, and the exercise comfort test. Valid signals were obtained when the EMG device was combined to the prototype for the rectus femoris muscle, indicating stable positioning of the device during exercise.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.142-147
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• 2008

Abdominal circumference changes due to breathing by the respiratory muscle activity such as diaphragm, which would partially represent the lung volume variation. The present study introduced conductive rubber molded in a cord shape incorporated with a patient's pants. The conductive rubber cord operated as a displacement transducer to measure the lung or abdominal volume changes. Signal extraction circuitry was developed to obtain the volume and its derivative(or the flow) signals followed by wireless transmission based on the Zigbee communication protocol in a size of $65mm{\times}105mm$ easily put in pocket. Breathing frequency was accurately evaluated and breath pattern analysis seemed feasible, since respiratory behaviours such as maximal inspiration and cough were well identified. Remote wireless receiver module also enabled to monitor both volume and flow signals during resting breathing on a PC terminal.