• Fashion & Textile Research Journal
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• v.2 no.4
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• pp.300-307
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• 2000

The purpose of this study was to classify and analyze the body type of obese boys who are school year for 9 to 11 years. A total of 49 body measurements were collected for this study including both direct and indirect measurements (33 variables from the direct anthropometric data, 16 variables from the indirect anthropometric data). Data from anthropometric measurement were analyzed using descriptive, factor and cluster analysis. The obese boys investigated in this project were in the category of average height 146.31 cm, weight 52.17 kg. The values for the study were compared to values from the National Anthropometric Survey of Korea. As the result of factor analysis for the classification of body type, 6 factors were extracted from all items. The first was transverse size of upper body, also, the second was its longitudinal size. The third was thicknesses of front and back at side views. The fourth was shoulder shape. The fifth was upper body angle factor. The sixth was upper body length. The body form was classified with cluster analysis, using factor score. The shape of the body was classified in 3 types.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.4
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• pp.289-296
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• 2005

This study aims to measure maximum holding times(MHTs) of symmetric and asymmetric whole body postures, and to compare three representative observational methods including OWAS, RULA, REBA, based on the MHTs. An experiment was conducted for obtaining the MHTs, in which hand position was used as experimental variable, and the MHT and subjective discomfort rating as dependent variables. The hand position was defined by the percentage of the shoulder height(%SH), the percentage of the arm reach(%AR) and rotation angle(R). The results showed that three independent variables of %SH, %AR and R significantly affected on the MHTs at ${\alpha}$=0.01, and that the MHTs were negatively linearly related to the discomfort scores of Borg CR10. It was also revealed that OWAS and REBA were less sensitive to postural stress than RULA. In addition, OWAS and REBA underestimated postural load of given postures compared to RULA. Therefore, it is recommended that among the three observational methods investigated in this study, RULA be used for a more precise evaluation of postural load.

• The Research Journal of the Costume Culture
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• v.13 no.3 s.56
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• pp.439-451
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• 2005

This study was to provide the fundamental data for the ease necessary to design clothes by investigating the variation of the upper body surface with the method of surgical tape. The subject were 8 young women in the standard somatotype. In the form of body surface according to arm movements, the shape of armscye circumference became gentle from the sunken form for the standing posture; scye depth became lower; lateral shoulder moved and rose toward the front center as the angle of arm movement became larger; scye depth is greatest in the standing. The items of horizontal ware largest in the standing posture except for front neck base circumference and front interscye breadth for side $90^{\circ}$ movement. In the items of vertical, while most of the front items increased but back ones generally decreased for all movement compared to the standing. After comparing differences in actual values between the form of body surface in the standing posture and the direct measurement, the following ease were suggested considering minimum measures to accommodate daily movements. Bust circumference/2 = 3cm; waist circumference/2 = 1.5cm; front interscye breadth/2 = 0.6cm; back interscye breadth/2 = 0.6cm; and underarm depth = 1.5cm

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.1-7
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• 2012

The purpose of this study was to investigate the pattern change of throwing in baseball after 15 weeks of participation in baseball class, by examining ball speed, trunk and upper body angles. The comparison was with 6 university students that haven't had any experience in baseball. 8 infra red cameras and 2 force platforms were used to collect the data. First, there was an increase in the speed of the ball after the class. Second, there was no significant difference in the allocated phases during the throw before and after class. Third, the release point was lower and more in front. Forth, there was an increase in the knee flexion at the left foot landing and release point. Finally, there was an increase in the maximum shoulder external rotation and pelvis angle. It is recommended that the coordination between the segments should be investigated to improve our understanding of the learning of throwing in future research.

• Fashion & Textile Research Journal
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• v.17 no.2
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• pp.258-264
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• 2015

This study provides abasis for the development of high functional cycle wear with clothing comfort and fitness for highschool boy cyclists by a comparison of the somatotype of highschool boys cyclists and general highschool boys. This study directly measured 44 anthropometric targeted cyclists across Korea. "The sixth national standard physical survey" data targeted 16 to 18-year-old male adolescents; subsequently, anthropometric measurement data was provided by 766 people for research. Highschool boy cyclists used t-test to compare the differences in body type. The results in this study are follows. Highschool boys cyclists(compared to regular highschool boys) indicated a great somatotype stature and weight. The differences in the cervical height and the acromion height results of, cyclist appeared smaller. Cyclists angle of shoulder was smaller. The upper body of highschool boys cyclist was greater than the difference between chest breadth and bust breadth with along biacromion length. The waist front length of the cyclist was a short cycle ride upon the attitude of the streamlined. Highschool boy cyclists indicated that the muscles of the arm portion was more developed compared to general highschool boys. The lower body had less abdominal fat with a significantly developed thigh and calf.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.693-699
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• 2009

This paper shows mechanical properties and behaviors of macro- and micro-structures on friction stir welded specimen with 6061-T6 aluminum alloy plate. It apparently results in defect-free weld zone jointed at welding conditions like the traverse speed of 267mm/min, tool rotation speed of 2500rpm, pin inserted depth of 4.5mm and tilting angle of $2^{\circ}$ with tool dimensions such as tool pin diameter of 5mm, shoulder diameter of 15mm and pin length of 4.5mm. The tensile stress ${\sigma}_T=228MPa$ and the yield point ${\sigma}Y=141MPa$ are obtained at the condition of traverse speed of 267mm/min and tool rotation speed of 2500rpm. With the constant rotation speed, the higher traverse speed become, the higher tensile stress and yielding point become. Vickers hardness for welding zone profile were also presented.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.1
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• pp.145-150
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• 2008

One of the unresolved questions in articular cartilage biomechanics is the magnitude of the dynamic modulus and tissue compressive strains under physiological loading conditions. The objective of this study was to characterize the dynamic modulus and compressive strain magnitudes of bovine articular cartilage at physiological compressive stress level and loading frequency. Four bovine calf shoulder joints (ages 2-4 months) were loaded in Instron testing system under load control, with a load amplitude up to 800 N and loading frequency of 1 Hz, resulting in peak engineering stress amplitude of ${\sim}5.8\;MPa$. The corresponding peak deformation of the articular layer reached ${\sim}27%$ of its thickness. The effective dynamic modulus determined from the slope of stress versus strain curve was ${\sim}23\;MPa$, and the phase angle difference between the applied stress and measured strain which is equivalent to the area of the hystresis loop in the stress-strain response was ${\sim}8.3^{\circ}$. These results are representative of the functional properties of articular cartilage in a physiological loading environment. This study provides novel experimental findings on the physiological strain magnitudes and dynamic modulus achieved in intact articular layers under cyclical loading conditions.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.61-70
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• 2005

The purpose of study was to investigate the kinematic variables of Kenmotsu motion in Parallel bars. To this study, by 3 dimensional kinematical analysis of 4 male national gymnasts participants in the 28th Athens Olympic Game in 2004, kinematic data collected using video camera. Coordinate data were smoothed by using a fourth-order Butterworth low pass digital filter with cutoff frequency of 6Hz. The conclusions were as follows. 1. In P2, because the constrained swing movement made the movement of a rising back difficult7, the movements of Reg. were performed at low position after Air phase. 2. In E5 event, for the shake of a stable handstand and applied techniques like a Belle(E-value), a Belle Piked(super E-value), a vertical velocity in E2, a horizontal velocity in E3 and a vertical velocity in E4 were necessary for high velocities. 3. In E4 event, it was appeared that for a flexible body's movement of a vertical up-flight, the large angle of the shoulder joint and the flexion & extension of the hip joint were necessary in Air phase and a long flight time and vertical displacement made Reg. movements stable at the high position.

• Safety and Health at Work
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• v.13 no.3
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• pp.315-325
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• 2022

Background: Firefighters are required to carry self-contained breathing apparatus (SCBA), which increases the risk of musculoskeletal disorders. This study assessed the newly recruited firefighters' internal forces and potential musculoskeletal disorders when carrying SCBA. The effects of SCBA strap lengths were also evaluated. Methods: Kinematic parameters of twelve male subjects running in a control condition with no SCBA equipped and three varying-strapped SCBAs were measured using 3D inertial motion capture. Subsequently, motion data and predicted ground reaction force were inputted for subject-specific musculoskeletal modeling to estimate joint and muscle forces. Results: The knee was exposed to the highest internal force when carrying SCBA, followed by the rectus femoris and hip, while the shoulder had the lowest force compared to the no-SCBA condition. Our model also revealed that adjusting SCBA straps length was an efficient strategy to influence the force that occurred at the lumbar spine, hip, and knee regions. Grey relation analysis indicated that the deviation of the center of mass, step length, and knee flexion-extension angle could be used as the predictor of musculoskeletal disorders. Conclusion: The finding suggested that the training of the newly recruits focuses on the coordinated movement of muscle and joints in the lower limb. The strap lengths around 98-105 cm were also recommended. The findings are expected to provide injury interventions to enhance the occupational health and safety of the newly recruited firefighters.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.67-79
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• 2003

The purpose of this study is to investigate the effective skill motion through the kinematic analysis of the Yurchenko Streched motion in new horse vaulting. The subjects in this study were 3 male gymnasts who were ranked as national athletes. After the 3D motion analysis, kinematic variables were analyzed to comparison with the difference between this study and the previous study(Yang, D. Y and Lee, C. S, 1999). As a result, the following conclusions was drawn; 1. In the board contact phase, this study showed a shorten contact time to maintain in condition highly extension of hip and hee angle than the previous study. 2. In the pre-flight phase, this study appeared more shortly flight duration time and horizontal flight displacement than the previous study. 3. In the horse contact phase, the contact duration time and horizontal displacement of COG shortened than the previous study, but appeared to the fast horizontal and vertical velocity and highly extension of shoulder an. 4. In the post-flight phase, a stable horse contact appeared to the increase of the flight duration time and the apex height during the post-flight. And it showed that these results have a stable and good landing.