• Journal of the Ergonomics Society of Korea
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• v.25 no.3
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• pp.17-24
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• 2006

In this paper, we propose a stress analysis on foot by lifting task attitudes. Maximum force and peak pressure were measured on 8 body regions by Pedar system in order to analysis the stress which is affected by task style and angle on foot when Manual Materials Handling task. As for the peak pressure of the whole foot as to the task height during the lifting task, the height from Knuckle to Shoulder was the least in the peak pressure. Also, as for the maximum force and the peak pressure of the whole foot as to the task angle during the lifting task, it could be seen that the more an angle increases, the stress influencing on a foot jumps. As for the maximum force and the peak pressure by foot region as to the task height in case of the lifting task, the height from Knuckle to Shoulder is indicated the smallest value in the maximum force and the peak pressure, thus there is necessary to attain the work design that considered this. Also, as for the maximum force by foot region as to the task angle in case of the lifting task, 0° tasking is indicated to be least, thus there is necessity to be attained the tasking design in a bid to prevent the existence of an angle. The results of this paper are thought to be helpful to the suitable work design, to the prevention of musculoskeletal disorders related to the lower limbs, and to the design of ergonomic safety shoes.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.107-113
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• 2014

PURPOSE: The purpose of this study was to investigate the correlation between craniovertebral angle (CVA) and cardiorespiratory function ($VO_2max$ and $VCO_2max$) in young adults. METHODS: For this study, the students of D college were questioned and 50 members of D college were participated in our research.. Side-view pictures of each subject were taken in standing positions, in order to assess forward head posture (FHP) by measuring the craniovertebral angle. The craniovertebral angle was measured as the angle between a horizontal line at C7 and a line from the tragus of the ear to the spinous process of C7. And $VO_2max$ and $VCO_2max$ were measured by Quark CPET (cosmed co, USA) while the subjects were performed the treadmill running task of a intensity to set with respiratory mask. Subjucts were Then Pearson's correlation coefficient was calculated to estimate the relationship between craniovertebral and cardiorespiratory function ($VO_2max$ and $VCO_2max$) using SPSS for window. RESULTS: There was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.528, p<0.05). And there was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.566, p<0.05). CONCLUSION: Foreward head posture is related to cardiorespiratory function, and it has a negative correlation with cardiorespiratory function.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.986-994
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• 2012

This paper is concerned with the application of the vision control algorithm with weighting matrix in robot point placement task. The proposed vision control algorithm involves four models, which are the robot kinematic model, vision system model, the parameter estimation scheme and robot joint angle estimation scheme. This proposed algorithm is to make the robot move actively, even if relative position between camera and robot, and camera's focal length are unknown. The parameter estimation scheme and joint angle estimation scheme in this proposed algorithm have form of nonlinear equation. In particular, the joint angle estimation model includes several restrictive conditions. For this study, the weighting matrix which gave various weighting near the target was applied to the parameter estimation scheme. Then, this study is to investigate how this change of the weighting matrix will affect the presented vision control algorithm. Finally, the effect of the weighting matrix of robot vision control algorithm is demonstrated experimentally by performing the robot point placement.

• Journal of the Ergonomics Society of Korea
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• v.18 no.2
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• pp.103-120
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• 1999

The purpose of this study was to evaluate the manual workload in repetitive wrist and finger motion. To evaluate manual workload, angular displacement of the joint, EMG of the muscle and subjective rating were studied. Both wrist motion and finger motion were studied. A screw-driving task was used for the wrist motion experiment. A keyboard typing task was used for the finger motion experiment. All finger joint angles and wrist angles were measured by an angle-measuring glove($CyberGlove^{TM}$, Virtual Technologies, Inc.). Surface EMG was recorded from FCU muscle and FDS muscle simultaneously with the angle measurement. Subjective ratings of exertion were also recorded using the modified Borg's CR-10 scale. Repetition rates of 0.5, 1, 2 motions per second were used with each task. As a result, manual workload increased with increasing repetitiveness. Peak spectral magnitude and frequency components corresponded closely with joint angular displacement amplitudes and repetition rates. Results of the correlation analysis showed that there were significant correlation among EMG, frequency-weighted motion and subjective measurement. Both EMG and frequency-weighted filtering showed consistent workload estimation with increasing task frequency. Subjective ratings showed slight over-estimation of the workload as the task frequency is increased.

• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.69-75
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• 2009

It is well-known that lifting capacity of a worker is influenced by body posture during the task. When a task analyst make use of RULA and REBA Trunk and upper arm angles are recorded in a separate item. It means that the interaction between the angles of two body segments may be ignored in a final score. The NLE(NIOSH Lifting Equation) has been used to supplement this problem. However, there is no study to validate the result of RWL (Recommended Workload Limit) under the existence of interactions between trunk and upper arm angles. The goal of this study was to assess the effect of the interaction between trunk and upper arm angles. Three responses, including NMVC(normalized maximum voluntary contraction), RWL(Recommended Weight Limit) and subjective judgment in psychophysical method (Borg's scale), were recorded according to the combinations of three trunk angles and nine upper arm angles. The results showed that lifting capacity is highly influenced by interaction of two body segments(trunk and upper arm). It means that the task workload has to be analyzed along with the interaction of trunk angles and upper arm angles when the task analyst assesses potential risk factors on the postures. This study may be able to be a fundamental study to develop an assessment method for lifting task analyses according to body postures.

• Journal of the Ergonomics Society of Korea
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• v.14 no.1
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• pp.69-81
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• 1995

Few studies on the biomechanical analysis of hand postures and tool handling tasks exist because of the lack of appropriate measurement techniques for hand force. A measurement system for the finger forces and joint angles for the analysis of manual tool handling tasks was developed in this study. The measurement system consists of a force sensing glove made from twelve Force Sensitive Resistors and an angle-measuring glove (Cyberglove$^{TM}$, Virtual technologies) with eighteem joint angle sensors. A biomechanical model of the hand using the data from the measurement system was also developed. Systems of computerized procedures were implemented inte- grating the hand posture measurement system, biomechanical analysis system, and the task analysis system for manual tool handling tasks. The measurement system was useful in providing the hand force data needed for an existing task analysis system used in CTD risk evaluation. It is expected that the hand posture measurement developed in this study will provide an efficient and cost-effective solution to task analysis of manual tool handling tasks.s.

• Journal of the Ergonomics Society of Korea
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• v.25 no.2
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• pp.11-22
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• 2006

The muscular-skeletal disorders(MSDs) that have become a major issue recently in Korean industrial safety area are mainly caused by manual material handling task. The objective of this study is to provide scientific data for the establishment of work safety standard for Korean workers through the experiments of lifting task under various conditions, in order to prevent the muscular-skeletal disorders in the industrial work site. Eight male college students were recruited as participants. Three different lifting frequencies(1, 3, 5 lifts/min) and three twisting angles(including the sagittal plane and two asymmetric angles; i.e., 0°, 45°, 90°) for symmetric and asymmetric tasks, respectively, with three lifting range from floor to knuckle height, knuckle to shoulder, floor to shoulder height for one hour's work shift using free style lifting technique were studied. The maximum acceptable weight of load(MAWL) was determined under the different task conditions, and the oxygen consumption, heart rate, and RPE were measured or recorded while subjects were lifting their MAWLs. The results showed that: (1) The MAWLs were significantly decreased as the task frequency and task angle increased.; (2) The heart rate, oxygen consumption, RPE significantly increased with an increase in lifting frequency although maximum acceptable weight of lift decreased.; (3) The highest heart rate and oxygen consumption was recorded at the lifting range of floor to shoulder, followed by floor to knuckle and knuckle to shoulder.; (4) The RPE value showed that subjects perceived more exertion at the high frequency rate of lifting task and lifting range of floor to shoulder height. (5) The modeling for MAWL using isometric strength, task angle and lifting frequency were developed. It is expected that use of the results provided in this study may prove helpful in reducing MMH hazards, especially from lifting tasks for Korean, and can be used as a basis for pre-employment screening.

• Physical Therapy Korea
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• v.22 no.2
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• pp.21-29
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• 2015

This study investigated the effect of a load of 15% body weight on trunk, pelvis and hip joint coordination and angle variability in subjects with and without chronic low back pain (CLBP) during an anterior load carriage task. Thirty volunteers participated in the study (15 without CLBP, 15 with CLBP). All participants were asked to perform an anterior carriage task with a load of 15% body weight. The outcome measures included the means and standard deviations for measurements of three-dimensional coordination and angle variability of the trunk, pelvis and hip joint. As CLBP patient group .06, control group .70, the correlation coefficient between the groups showed a significant difference only in trunk-pelvic in the sagittal plane (p<.05). Angle variability of CLBP patient group increased significantly in the trunk in frontal plane, the pelvis in all sagittal plane, frontal plane, transverse plane, and the hip in sagittal plane, the hip in frontal plane than angle variability of control group (p<.05). This results mean that the CLBP patient group showed a disconnected coordination pattern in the trunk-pelvis in the sagittal plane, an increased pelvic angle variability in all three planes, and hip angle variability in the sagittal, and frontal planes. The CLBP patient group may have developed a compensatory movement of the pelvis and hip joint arising from the changed stability due to the abnormal coordination patterns of the trunk-pelvic in the sagittal plane. Therefore, CLBP symptoms can potentially worsen in the pelvis and adjacent hip joint in CLBP patients who perform weight-related behaviors in their daily lives. Further research is needed to determine the three-dimensional characteristics of the electromyography and neuromuscular aspects of subjects with CLBP.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.64-70
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• 2016

Purpose: The purpose of this study was to evaluate performance reliability of stroke patients using kinematic analysis. Methods: A protocol to evaluate performance reliability was performed for three tasks on 20 stroke patients and 10 normal people. The tasks include hand to head (HH) task, hand to mouth (HM) task, and hand to target (HT) task. Results: The affected arms showed smaller joint angle, slower peak velocity, longer time to peak velocity for task performances than control group. Also, slower peak velocity and longer movement time for task performance in unaffected arm of stroke patients were obtained compared with the control group. Conclusion: Kinematic analysis is very useful quantitative tool to provide understanding on upper extremity function of stroke patients.

• The Journal of Korean Society for Neurotherapy
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• v.22 no.3
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• pp.25-29
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• 2018

Purpose In this study, 45 students were divided into task - oriented group, task - oriented intermittent group, and continuous group, and the effect of each variable on learning was changed to angle of the arms' we checked. Methods This study was conducted for 45 days from March 13 to 18, 2017 for five days in the 20 generals living in Changwon city. Dart and goniometer were used for the measurement. In the exercise program, darts were placed on a smooth, hard surface of 1.5M height and the distance to the subject was set 1.5m away. In the dart throw practice, all three groups were marked with an elbow flexion $30^{\circ}$ on the wall, and the subjects were instructed to throw the dart at that point. Results Comparisons between groups showed significant differences between the continuous task-oriented training group and the intermittent task-oriented training group and the control group at the end of training (*** P <0.001). Conclusion This study showed that the intermittent task-oriented training method showed the highest effect (*** P <0.001), which proved that the intermittent method is the most effective exercise method among the three groups.