• Journal of Biomedical Engineering Research
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• v.31 no.2
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• pp.141-150
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• 2010

The purpose of this study was to analyze the golf swing motion for a soft golf clubs and regular golf club. Soft golf is a newly developed recreational sports for all ages, including the elderly and the beginners of golf. To quantify the effect of using soft golf club, which much lighter club than regular clubs, a motion analysis has been performed using a 3D optoelectric motion tracking system that utilizes active infrared LEDs and near-infrared sensors. The subject performed swing motion using a regular golf club and a soft golf club in turn. The obtained motion capture data was used to build a 3D computer simulation model to obtain left wrist, elbow shoulder and lumbar joint force and torque using inverse and forward dynamics calculations. The joint force and torque during soft golf swing were lower than regular golf swing. The analysis gave better understanding of the effectiveness of the soft golf club.

• The KIPS Transactions:PartB
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• v.9B no.4
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• pp.453-458
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• 2002

It is not easy to analyze dynamic sports motion, but it can be done easily by using an interactive playback of the recorded motion. Everybody is able to capture a golf swing owing to the popularization of PC and digital camcorder in these days. In this study, the system that can provide golf swing analysis is selected and implemented. Furthermore, editing method that can represent motion is applied and moving object tracking algorithm that can make this profess easy is applied to provide easy golf swing analysis.

• Korean Institute of Interior Design Journal
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• v.13 no.3
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• pp.187-196
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• 2004

The purpose of this study is to develope'a digital space design process using user's motion data' through a theoretical and experimental study. In the progress of developing a developing of design process, this study was concentrated on searching a digital method applying user's interactive reflections. As introducing a concept of space form being generated by user's experiences, we proposed'a digital design process using user's motion data'. In the experimental stage, user's motion data were extracted and transferred as digital information by user behavior analysis, optical motion capture system, immersive VR system, 3D softwares com computer programming. As the result of this study, another useful digital design process was embodied by building up a digital form-transforming method using 3D softwares providing internal algorithm. This study would be meaningful in terms of attempting a creative and interactive digital space design method, avoiding dehumanization of existing ones through the theoretical study and the experimental approach.

• Fashion & Textile Research Journal
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• v.14 no.1
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• pp.109-121
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• 2012

This study aims at developing ergonomics patterns for the sleeve of structural firefighting protective clothing through 3D motion analysis in order to ensure efficiency and safety of firefighters who are exposed to harmful environment at work. A new research pattern was developed by applying the total results of 3D motion analysis, changes of body surface length measurements, and 2D data on 3D body shape analysis on the size 3 patterns of the existing coat sleeve. For the sleeves, we used the body surface length of the range of shoulder's flexion and the joint angle of the range of wrist's ulnar deviation. And for the production of structural firefighting protective clothing using the research pattern, we recruited a recognized producer of structural firefighting protective clothing designated by KFI. Unlike everyday clothes, structural firefighting protective clothing should be able to fully protect the wearers from the harmful environment that threatens their lives and should not cause any restrictions on their movement. Therefore, the focus of research and development of such protective clothing should be placed on consistent development of new technologies and production methods that will provide protection and comfort for the wearer rather than production cost reduction or operational efficiency. This study is meaningful as it applied 3D motion analysis instead of the existing methods to develop the patterns. In particular, since 3D motion analysis enables the measurement of the range of motion, there should be continuous research on the development of ergonomics patterns that consider workers' range of motion.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1391-1398
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• 2011

Biomechanical analysis of arm motion during steering was performed using a motion analysis technique. Three-dimensional position data for each part of arm are fed into an interactive model combining a musculoskeletal arm model and the mechanical steering system to calculate joint angles and torques using inverse kinematic and dynamic analyses, respectively. The analysis shows that elbow pronation/supination, wrist flexion/extension, shoulder adduction/abduction, and shoulder flexion/extension have significant magnitudes. Sensitivity analysis of the arm joint motion with respect to seating posture and steering wheel configuration is carried out to investigate the qualitative influence of the seating posture and driver's seat configuration on the steering behavior.

• Physical Therapy Korea
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• v.29 no.4
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• pp.262-268
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• 2022

Background: Virtual reality (VR) programs based on motion capture camera are the most convenient and cost-effective approaches for remote rehabilitation. Assessment of physical function is critical for providing optimal VR rehabilitation training; however, direct muscle strength measurement using camera-based kinematic data is impracticable. Therefore, it is necessary to develop a method to indirectly estimate the muscle strength of users from the value obtained using a motion capture camera. Objects: The purpose of this study was to determine whether the pedaling speed converted using the VR engine from the captured foot position data in the VR environment can be used as an indirect way to evaluate knee muscle strength, and to investigate the validity and reliability of a camera-based VR program. Methods: Thirty healthy adults were included in this study. Each subject performed a 15-second maximum pedaling test in the VR and built-in speedometer modes. In the VR speedometer mode, a motion capture camera was used to detect the position of the ankle joints and automatically calculate the pedaling speed. An isokinetic dynamometer was used to assess the isometric and isokinetic peak torques of knee flexion and extension. Results: The pedaling speeds in VR and built-in speedometer modes revealed a significantly high positive correlation (r = 0.922). In addition, the intra-rater reliability of the pedaling speed in the VR speedometer mode was good (ICC [intraclass correlation coefficient] = 0.685). The results of the Pearson correlation analysis revealed a significant moderate positive correlation between the pedaling speed of the VR speedometer and the peak torque of knee isokinetic flexion (r = 0.639) and extension (r = 0.598). Conclusion: This study suggests the potential benefits of measuring the maximum pedaling speed using 3D depth camera in a VR environment as an indirect assessment of muscle strength. However, technological improvements must be followed to obtain more accurate estimation of muscle strength from the VR cycling test.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.117-125
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• 2015

In the modern age, it is important for people to maintain a good sitting posture because they spend long hours sitting. Posture correction treatment requires a great deal of time and expenses with continuous observation by a specialist. Therefore, there is a need for a system with which users can judge and correct their postures on their own. In this study, we collected users' postures and judged whether they are normal or abnormal. To obtain a user's posture, we propose a four-joint motion capture system that uses inertial sensors. The system collects the subject's postures, and features are extracted from the collected data to build a database. The data in the DB are classified into normal and abnormal postures after posture learning using the K-means clustering algorithm. An experiment was performed to classify the posture from the joints' rotation angles and positions; the normal posture judgment reached a success rate of 99.79%. This result suggests that the features of the four joints can be used to judge and help correct a user's posture through application to a spinal disease prevention system in the future.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.1-8
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• 2018

Objective: The purpose of this study is to investigate the differences in biomechanical variables of golf driving motion according to gender. Method: A total of 21 healthy golfers (11 men and 10 women) who have more than 5 years of professional experience and have been registered in the Korea Golf Association was recruited. A 250-Hz 8-camera motion capture system (MX-T20, Vicon, LA, USA) was used to capture the motion trajectories of a total of 42 reflective markers attached to the golfer's body and club. Moreover, two 1,000-Hz AMTI force plates (AMTI OR6-7-400, AMTI, MA, USA) were used to measure the ground reaction force. The mean and standard deviation for each parameter were then calculated for both groups of 21 subjects. SPSS Windows version 23.0 was used for statistical analysis. The independent t-test was used to determine the differences between groups. An alpha level of .05 was utilized in all tests. Results: There were differences in joint angles according to gender during golf driver swing. Men showed a statistically significantly higher peak joint angle and maximum range of angle in sagittal and frontal axis of the pelvis, hip, and knee. Moreover, women's swing of the pelvis and hips was found to have a pattern using the peak joint angle and range of angle in the vertical axis of the pelvis and hip. There were the differences in peak joint moment according to gender during golf driver swing. Men used higher joint moment in the downswing phase than women in the extensor, abductor, and external rotator muscles of the right hip; flexor and adductor muscles of left hip joint; and flexor and extensor muscles of the right knee. Conclusion: This result reveals that male golfers conducted driver swing using stronger force of the lower body and ground reaction force based on strength of hip and thigh than female golfers.

• PNF and Movement
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• v.18 no.2
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• pp.287-296
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• 2020

Purpose: The study aims were to develop a wearable inertial sensor-based gait analysis device that uses machine learning algorithms, and to validate this novel device using temporal gait parameters. Methods: Thirty-four healthy young participants (22 male, 12 female, aged 25.76 years) with no musculoskeletal disorders were asked to walk at three different speeds. As they walked, data were simultaneously collected by a motion capture system and inertial measurement units (Reseed®). The data were sent to a machine learning algorithm adapted to the wearable inertial sensor-based gait analysis device. The validity of the newly developed instrument was assessed by comparing it to data from the motion capture system. Results: At normal speeds, intra-class correlation coefficients (ICC) for the temporal gait parameters were excellent (ICC [2, 1], 0.99~0.99), and coefficient of variation (CV) error values were insignificant for all gait parameters (0.31~1.08%). At slow speeds, ICCs for the temporal gait parameters were excellent (ICC [2, 1], 0.98~0.99), and CV error values were very small for all gait parameters (0.33~1.24%). At the fastest speeds, ICCs for temporal gait parameters were excellent (ICC [2, 1], 0.86~0.99) but less impressive than for the other speeds. CV error values were small for all gait parameters (0.17~5.58%). Conclusion: These results confirm that both the wearable inertial sensor-based gait analysis device and the machine learning algorithms have strong concurrent validity for temporal variables. On that basis, this novel wearable device is likely to prove useful for establishing temporal gait parameters while assessing gait.

• 한국체육학회지인문사회과학편
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• v.53 no.5
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• pp.521-531
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• 2014

The purposes of this study were to evaluate the effect of normalization by dimensionless number of Hof(1996) and to analysis the gait pattern for 20s Korean males and females. Subjects are selected in accordance with classification system of Korean standard body figure and age. Experimental equipment is the Motion capture system. Subjects who are walked at a self-selected normal walking speed were photographed using the Motion capture system and analyzed using 3D motion analysis method with OrthoTrak, Cortex, Matlab and SPSS for a statistical test. When used to normalize data, there are no differences of statistical significances between gender in all spatiotemporal variables. I concluded that gait research for mutual comparison requires a normalization by dimensionless number to eliminate the effects of the body size and to accurate statistical analysis.