Comparison of Shoulder Total Rotational Range of Motion and External to Internal Rotation Strength Ratio between Assembly Line Workers with and without Subacromial Pain Syndrome

Gyeong-tae Gwak(Gyeong-tae Gwak),Young-soo Weon(Young-soo Weon),Jun-hee Kim(Jun-hee Kim) KEMA학회 2022 근골격계과학기술학회 Vol.6 No.1

Background Subacromial pain syndrome (SAPS) is one of the causes of shoulder pain in workers performing repetitive upper extremity movements. However, there have been no studies on physical characteristics such as shoulder total rotational range of motion (ROM) and external to internal rotation muscle strength ratio of workers. Purpose The purpose of this study was to compare the total rotational ROM and external to internal rotation muscle strength ratio in workers with and without SAPS. Study design A cross-sectional study Methods This study included 35 workers with SAPS and 32 workers without SAPS. The total rotational ROM were measured using Smart KEMA motion sensor, and external to internal rotation muscle strength were measured using Smart KEMA pulling sensor. Results The results showed that there were significant differences in the total rotation ROM between the groups (p<0.05). However, no significant difference was found in the external to internal rotation muscle strength ratio (p>0.05). Conclusions Assembly line workers with SAPS had limited total rotational ROM. However, the ratio of external to internal rotation muscle strength ratio was not different for workers without SAPS. These characteristics can be considered factors that should be considered in evaluating workers with SAPS and establishing a treatment plan.

A Multi-Layer Perceptron Neural Network for Predicting the Diagnosis of Osteoporosis in Women Using Physical Activity Factors

Gwak Gyeong-tae,김준희,Hwang Ui-jae,정성훈,안선희 KEMA학회 2023 근골격계과학기술학회 Vol.7 No.2

Background Osteoporosis (OP) is a bone disease caused by a decrease in bone mineral density (BMD). OP is common in women because BMD gradually decreases after age 35. OP due to decreased BMD is highly likely to cause fatal traumatic injuries such as hip fracture. Purpose The purpose of this study was developed and evaluated a multi-layer perceptron neural network model that predicts OP using physical characteristics and activity factors of adult women over the age of 35 whose BMD begins to decline. Study design Cross-sectional study. Methods Data from KNHANES were used to develop a multi-layer perceptron model for predicting OP. Data preprocessing included variable selection and sample balancing, and LASSO was used for feature selection. The model used 5 hidden layers, dropout and batch normalization and was evaluated using evaluation scores such as accuracy and recall score calculated from a confusion matrix. Results Models were trained and evaluated to predict OP using selected features including age, quality of life index, weight, grip strength and average working hours per week. The model achieved 76.8% accuracy, 74.5% precision, 80.5% recall, 77.4% F1 score, and 74.8% ROC AUC. Conclusions A multi-layer perceptron neural network for predicting OP diagnosis using physical characteristics and activity factors in women aged 35 years or older showed relatively good performance. Since the selected variables can be easily measured through surveys, assessment tool, and digital hand dynamometer, this model will be useful for screening elderly women with OP or not in areas with poor medical facilities or difficult access.

Relationship between Cross-Sectional Area and Function of Core Muscles: An MRI Study

Gwak Gyeong-tae,황의재,Jung Sung-hoon,김준희,권오윤 KEMA학회 2022 근골격계과학기술학회 Vol.6 No.2

Background Particular attention has been paid to the core muscles because they serve as a muscular corset that works as a unit to stabilize the body and spine. Training programs for improving core stability often target improving core strength and endurance. Increased muscle size is also an expected effect of training programs. However, the relationship between core muscle cross-sectional area (CSA) and strength, stability, and clinical core test scores has not been identified. Purpose To investigate the relationship between core muscle CSA and muscle functions (strength, endurance, and stability). Study design A cross-sectional study Methods Fifty healthy participants (24 men, 26 women) participated in this study. The CSA of core muscle was measured using MRI. Maximal isometric trunk flexor strength, endurance, the score of double leg loading test were used to measure core muscle function. The relationship between core muscle CSA and muscle function was examined by Pearson’s correlation coefficient and Spearman rho correlation coefficient. Results Maximal isometric trunk flexor strength and side bridge strength were positively correlated with core muscle CSA. The isometric endurance test scores also showed a positive correlation with core muscle CSA except for the score of trunk flexor endurance test. Conclusions Only core strength showed moderate to excellent correlation with core muscle CSA. These findings indicate that core training to achieve muscle hypertrophy could lead to improved core strength but not core endurance.

Prediction Model for the Risk of Scapular Winging in Young Women Based on the Decision Tree

Gyeong-tae Gwak,안선희,Jun-hee Kim,Young-soo Weon,권오윤 한국전문물리치료학회 2020 한국전문물리치료학회지 Vol.27 No.2

Background: Scapular winging (SW) could be caused by tightness or weakness of the periscapular muscles. Although data mining techniques are useful in classifying or predicting risk of musculoskeletal disorder, predictive models for risk of musculoskeletal disorder using the results of clinical test or quantitative data are scarce.Objects: This study aimed to (1) investigate the difference between young women with and without SW, (2) establish a predictive model for presence of SW, and (3) determine the cutoff value of each variable for predicting the risk of SW using the decision tree method.Methods: Fifty young female subjects participated in this study. To classify the presence of SW as the outcome variable, scapular protractor strength, elbow flexor strength, shoulder internal rotation, and whether the scapula is in the dominant or nondominant side were determined.Results: The classification tree selected scapular protractor strength, shoulder internal rota-tion range of motion, and whether the scapula is in the dominant or nondominant side as predictor variables. The classification tree model correctly classified 78.79% (p = 0.02) of the training data set. The accuracy obtained by the classification tree on the test data set was 82.35% (p = 0.04).Conclusion: The classification tree showed acceptable accuracy (82.35%) and high specific-ity (95.65%) but low sensitivity (54.55%). Based on the predictive model in this study, we suggested that 20% of body weight in scapular protractor strength is a meaningful cutoff value for presence of SW.

Machine Learning vs. Logistic Regression for Classifying Pressure Pain Hypersensitivity Based on Postural Analysis Data in Food Service Workers with Nonspecific Neck/Shoulder Myofascial Pain

Gwak Gyeong-tae,황의재 KEMA학회 2023 근골격계과학기술학회 Vol.7 No.2

Background Pressure pain hypersensitivity (PPH) is used to measure pain sensitivity in deep tissues, but factors contributing to PPH remain unclear. Abnormal neck and scapula posture are thought to play a role in shoulder pain. Traditional statistical methods like logistic regression have limitations in capturing complex relationships, while machine learning (ML) can model nonlinear relationships effectively. Purpose The purpose of the present study was to develop, evaluate, and compare the predictive performance of ML models and logistic regression for classifying food service workers (FWs) with and without PPH based on postural analysis data. Study design Cross sectional study. Methods FWs (n=150) meeting specific criteria were assessed for PPH and underwent postural analysis. ML algorithms (logistic regression, neural network, random forest, gradient boosting, decision tree, and support vector machine) were used for classification. Model performance was evaluated using the area under the curve (AUC), accuracy, recall, precision, and F1 score. Feature importance was assessed. Results Gradient boosting exhibited the best performance (AUC: 0.867) in classifying PPH, followed by random forest (AUC: 0.822) in the test dataset. Logistic regression performed less effectively (AUC: 0.613). For feature importance analysis, scapular downward rotation ratio, forward head posture, BMI and rounded shoulder angle were the top four important predictors of PPH in gradient boosting model. Conclusions Gradient boosting, along with identified predictors, offers promise for early intervention and risk assessment tools in addressing musculoskeletal pain in food service workers.

요양원 복지사의 임파워먼트가 직무만족에 미치는 영향

곽경자 ( Gyeong Ja Gwak ),이영희 ( Yeong Hee Lee ),최태환 ( Tae Hwan Choi ) 한국노인의료복지학회 2011 노인의료복지연구 Vol.3 No.1

The purpose of the study is to suggest the measure for the improvement of job satisfaction and level of empowerment of sanatoriums` social workers by analyzing factors of empowerments` effect on the job satisfaction, and investigating level of empowerment and job satisfaction of social workers of sanatoriums for the elderly and the handicapped. The result of investigation and analysis on subjects of 420 social workers of sanatoriums for the elderly and the handicapped in Youngnam area for this is as follows: First, job characteristic that is empowerments` influence factor of sanatoriums` social workers is appeared in order of feedback, and function variety, and in organization characteristic is appeared in order of leadership, reward, and employee development. Second, level of empowerment that is recognized by sanatoriums` social workers is appeared a little higher than normal level and significance is appeared highest, and next are capability, self-determination ability, and influence. Third, features that showed significant difference with significance in general characteristic of sanatoriums` social workers were ‘sex’, ‘marital status’, and ‘religion’, and features that showed significant difference with capability were sex, age, marital status, academic background, and employment history. And features that showed significant difference with self-determination ability were sex, age, marital status, and employment history, and features that showed significant difference with influence were sex, age, employment history and types of facilities. Fourth, the whole average of job satisfaction of sanatoriums` social workers was 3.82 out of 5, which is generally high, features that showed significant difference statistically were age, marital status, academic background, employment history, and types of facilities. Thus, job satisfaction was appeared as high as ‘more than age of thirty’ in age, ‘married’ in marital status, ‘under graduates of colleges’ in academic background, and ‘less than three years’ in employment history. Fifth, as for factors that had influence on job satisfaction, the indirect effect with empowerment was appeared that had significant effect in organization characteristic, and had few effect in organization features. On these results, practical measures to increase job satisfaction of sanatoriums` social workers are as follows: First, political approach is required to standardize duty system(by various types of facilities and clients` characteristic) of social workers of sanatoriums for elderly and the handicapped, and help to do the role as professionals with giving better treatment and building self-respect by enough reward. Second, to suggest chances to perform the responsibility for the duty of the scenes by the regular supervision, establish regular supervision system of social workers of sanatoriums for the elderly and the handicapped, and the extension of duty to increase the functional varieties. Third, it is required to motivate to have self confidence for the work and to use potential ability with transforming leadership, and to have more chances of education for the self-development. To increase job satisfaction of sanatoriums` social workers who give direct services in sanatoriums for the elderly and the handicapped, more active and positive empowerment`s level improvement is in need by improvement of empowerment for them.

Comparison of the Flexion-Relaxation Ratio of the Hamstring Muscle and Lumbopelvic Kinematics During Forward Bending in Subjects With Different Hamstring Muscle Flexibility

Chang-ho Kim,Gyeong-tae Gwak,Oh-yun Kwon 한국전문물리치료학회 2017 한국전문물리치료학회지 Vol.24 No.4

Background: Flexion-relaxation phenomenon (FRP) was a term which refers to a sudden onset of myoelectric silence in the erector spinae muscles of the back during standing full forward flexion. Hamstring muscle length may be related to specific pelvic and trunk movements. Many studies have been done on the FRP of the erector spinae muscles. However, no studies have yet investigated the influence of hamstring muscle flexibility on the FRP of the hamstring muscle and lumbopelvic kinematics during forward bending. Objects: The purpose of this study was to examine the flexion-relaxation ratio (FRR) of the hamstring muscles and lumbopelvic kinematics and compare them during forward bending in subjects with different hamstring muscle flexibility. Methods: The subjects of two different groups were recruited using the active knee extension test. Group 1-consisted of 13 subjects who had a popliteal angle under 30°; Group 2-consisted of 13 subjects who had a popliteal angel above 50°. The kinematic parameters during the trunk bending task were recorded using a motion analysis system and the FRRs of the hamstring muscles were calculated. Differences between the groups were identified with an independent t-test. Results: The subjects with greater hamstring length had significantly less lumbar spine flexion movement and more pelvic flexion movement. The subjects with greater pelvic flexion movement had a higher rate of flexion relaxation during full trunk bending (p<.05). Conclusion: The results of this study suggest that differences in hamstring muscle flexibility might cause changes in people’s hamstring muscle activity and lumbopelvic kinematics.

Comparison of Foot Pressure Distribution During Single-leg Squat in Individuals With and Without Pronated Foot

Ahn Il-kyu,Gwak Gyeong-tae,Hwang Ui-jae,Yoo Hwa-ik,Kwon Oh-yun 한국전문물리치료학회 2024 한국전문물리치료학회지 Vol.31 No.1

Background: Single-leg squat (SLS)s are commonly used as assessment tool and closed kinetic exercises are useful for assessing performance of the lower extremities. Pronated feet are associated with foot pressure distribution (FPD) during daily activities. Objects: To compare the FPD during SLSs between groups with pronated and normal feet. Methods: This cross-sectional study included 30 participants (15 each in the pronated foot and control groups) are recruited in this study. The foot posture index was used to distinguish between the pronated foot and control groups. The Zebris FDM (Zebris Medical GmbH) stance analysis system was used to measure the FPD on the dominant side during a SLS, which was divided into three phases. A two-way mixed-model ANOVA was used to identify significant differences in FPD between and within the two groups. Results: In the hallux, the results of the two-way mixed-model ANOVAs revealed a significant difference between the group and across different phases (p < 0.05). The hallux, and central forefoot were significantly different between the group (p < 0.05). Moreover, significant differences across different phases were observed in the hallux, medial forefoot, central forefoot, lateral forefoot, and rearfoot (p < 0.05). The post hoc t-tests were conducted for the hallux and forefoot central regions. In participants with pronated foot, the mean pressure was significantly greater in hallux and significantly lower, in the central forefoot during the descent and holding phases. Conclusion: SLSs are widely used as screening tests and exercises. These findings suggest that individuals with pronated feet should be cautious to avoid excessive pressure on the hallux during the descent-to-hold phase of a SLS.

카바모일기를 측쇄로 갖는 방향족 폴리아미드의 합성 및 물성(ll) -모델 반응-

오태진,곽경진,서문호,O, Tae-Jin,Gwak, Gyeong-Jin,Seo, Mun-Ho 한국섬유공학회 1995 한국섬유공학회지 Vol.32 No.4

The changes of chemical structure along a polymer chain during thermal and chemical treatment were examined by FT-lR spenxoscopy. The thermal cyclization of poly(2,5-diaminobenzamide-terephthalamide) (PDBTA) and poly(4,4'-dia- vino-6-carbamoylbenzanilide-terephthalamide) (polyul-DACB -TPC)) in the absence and in the presence of catalyst such as LiCl produces both a large amount of quinazolone and a small a mount of benzoxazinone along a polymer chain; the amount of quinazolone and benzoxazinone formed by dehydration and deamination reaction through condensation reaction of pendant carbamoyl fyoup and amide bond along a polymer chain during thermal treatment of the polymer was determined using calibration curve obtained with the absorbance of model compounds of 6-benzoylamino-2-pheny1-4-(3H) -quinazolone and of 6-benzoylamino-2-phenyl-4H-3,1-benzoxazin-Lone measured at wavenumber of 1358 and 1742cm -1 It turns out that thermal cyclopolycondensation of PDBTA without LiCl at 270'I produces 76% of quinazolone and 24% of benzoxazione as well as with LiCl gives 89% and 11%, respectively. The chemin cyclization of PDBTA and poly(p-DACB-TPC) in fuming H2SO4, on the contrary, produces nitril groups exclusively along a polymer chain via strong dehydration reaction of carbamoyl groups along polymer chain in fuming H2SO4 ; it is confirmed by chemical treatment in fuming H2SO4 of model compound Rr, leis(2,5-N-benzoyldiamino) benzamide, which gives around 80% of bis(2,5-N-benzoyldiamino) benzonitrile, VII.

Synthesis of hydrotalcite type layered double hydroxide with various Mg/Al ratio and surface charge under controlled reaction condition

Lee, Ji-Yeong,Gwak, Gyeong-Hyeon,Kim, Hyoung-Mi,Kim, Tae-il,Lee, Gyeong Jin,Oh, Jae-Min Elsevier 2016 Applied clay science Vol.134 No.1

<P><B>Abstract</B></P> <P>In order to control Mg/Al ratio in hydrotalcite type layered double hydroxide (LDH), LDH was prepared through coprecipitation under varied synthetic parameters such as initial Mg/Al ratio (from 1 to 20) in metal solution and coprecipitation pH (9.5, 10, 10.5 and 11). Phase evolution of hydrotalcite or impurities was examined with powder X-ray diffraction pattern and the Mg/Al ratio in final product was evaluated with inductively coupled plasma-atomic emission spectroscopy. It was found that the nominal Mg/Al ratio did not correspond to the final values, showing narrow correlation range between 1 and 3 at relatively low pH~9.5. By raising coprecipitation pH upto 11, Mg/Al ratio successfully increased in final LDH product upto 15.4. Under controlled initial Mg/Al ratio and coprecipitation pH, various LDHs with Mg/Al ratio between 1 and 16, which corresponded to layer charge density between 0.5 and 6(+)/100Å<SUP>2</SUP>, were obtained. The charge density and surface charge of LDHs exhibited linear correlation, showing zeta potential value 16–40mV at neutral pH.</P> <P><B>Highlights</B></P> <P> <UL> <LI> LDHs with various Mg/Al ratio were prepared. </LI> <LI> Starting Mg/Al ratio and pH was controlled respectively in coprecipitation reaction. </LI> <LI> Mg/Al ratio between 1.44 and 15.43 was obtained under controlled conditions. </LI> <LI> Zeta potential of LDH was highly dependent on the Mg/Al ratio. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>