Issues : JET is a peer-reviewed, open-access scientific journal : Journal of Ergonomic Technology (JET)

Journal of Ergonomic Technology (JET)
ISSN 2432-1575


Pain related to breastfeeding in seated and side-lying positions: assessment and recommendations for improved guidance
Publish Date : 2017/10/24  Vol.17
Authors : 
Makiko AOKI, Kanagawa Institute of Technology
Satoshi SUZUKI, Kanagawa Institute of Technology
Hidenobu TAKAO, Kanagawa Institute of Technology
Fumitaka IKARASHI, Graduate School of Engineering, Kanagawa Institute of Technology
Report Outline : 
Purpose: To explore the relationship between breastfeeding positions and pain in the upper arms and shoulders.
Subjects and Methods: Twelve subjects with breastfeeding experience participated in an experiment and survey. In the experiment, subjects embraced two dummy infants with different weights, in six different positions, such as the cradle hold and side-lying hold, while electromyography (EMG) and video were recorded at six sites: the right and left forearms, upper arms, and shoulders. The survey asked for responses to 37 items such as sites where pain was felt during breastfeeding, type of hold during breastfeeding, and guidance received from medical institutions or other advisors.
Results: The 11 subjects who provided valid data were analysed. In training and practice with breastfeeding positions at medical institutions, only two subjects had received guidance on the side-lying hold, but 10 had used it. In terms of the positions of the upper arms in each hold, seven patterns were observed for the side-lying hold. Spearman’s rank correlation coefficient for left/right location of chronic pain and frequency of breastfeeding with the left/right breast was 0.95 (p<0.01). Eight of 10 subjects who had performed the side-lying hold felt short-term pain in the upper arm and shoulder of the breastfeeding side (the bottom side in the lateral decubitus position).
Conclusion: Of six breastfeeding positions, the one most frequently linked to pain was the side-lying hold. It also became clear that uneven breastfeeding with the right and left breasts in the side-lying hold, or the use of a self-taught side-lying hold position, produced short-term pain that was linked to lactation-stage pain. This shows that guidance on the proper use of the side-lying hold is needed. There is also a need for further investigation that distinguishes between different side-lying hold positions, to support teaching of appropriate body positions. Research on breastfeeding positions has the potential to reduce the burden of child-rearing on mothers and contribute to a healthier child-rearing environment.

Keywords: Breastfeeding positioning, EMG, Pains of upper arms and shoulder, Side-lying, After birth and parenting support
Count : 1271
Validity and reliability of Leap Motion Controller for assessing grasping and releasing finger movements
Publish Date : 2017/10/04  Vol.17
Authors : 
Shuntaro OKAZAKI, Faculty of Human Sciences, Waseda University, Saitama, Japan
Yoshihiro MURAOKA, Faculty of Human Sciences, Waseda University, Saitama, Japan
Risa SUZUKI, Faculty of Human Sciences, Waseda University, Saitama, Japan
Report Outline : 
Objective: The leap motion controller (LMC) is a motion sensor that has recently become available and has advantages in terms of cost, size, and accuracy. However, it has not been fully investigated whether the LMC has sufficient accuracy for clinical assessments, particularly finger flexion and extension, which are important for diagnosis and prognosis in stroke or cerebral palsy patients. Herein, we have tested the validity and reliability of the LMC for measuring the grasp and release of finger movements.
Materials and methods: A healthy participant repeated finger flexion and extension movements, and his fingertip position was measured using an LMC from the palmar, ulnar, and dorsal sides of the hand. The fingertip position was also measured using an electromagnetic motion tracker and a video. The finger movement detected by the LMC was compared with those detected by the other instruments.
Conclusions: The LMC had a higher reliability in detecting the fingertip position by sensing it from the palmar or dorsal side of the hand, compared with the ulnar side. In the palmar/dorsal side measurements, an underestimation in the amplitude of the finger movement was shown in the middle range of its excursion compared to video-detected movement. However, the underestimation resulted in a highly correlated, proportional bias, especially in the palmar-side measurement, and could be calibrated by a nonlinear regression analysis. The palmar side measurement was thus the most suitable for evaluating the finger flexion and extension. We concluded that by taking into consideration the range of excursion and appropriate calibration, the validity and reliability of the LMC is sufficient for the quantitative evaluation of finger flexion and extension in laboratory experiments and also in clinical settings.

Keywords: Motion capture; Spasticity; Grasping; Bland–Altman plot
Count : 1452
Ergonomic evaluation of mobile work type office environments
Publish Date : 2017/09/23  Vol.17
Authors : 
Satoru SAITO, Department of Arts and Science, Faculty of Fundamental Science Engineering, Waseda University
Hiroki KITAJIMA, Labor and Science Research Institute
Toshiki YAJIMA, Kokuyo Corporation Furniture Business Hadquarters
Junichi NINOMIYA, Inaba International Corporation
Kunihisa NAKAYAMA, YAMAGIWA Corporation
Sachiyo FURUSAKA, WFM Women's Facility Management/Fulliaison
Reiko MITSUYA, Science and Technology Research Institute, Waseda University
Report Outline : 
Purpose: In recent years, there have been changes in awareness and institutional systems relating to work due to factors such as innovation in IT technology and adoption of work-life balance. In particular, some companies have introduced a new mobile work-style where employees are able to work anytime, anywhere. The aims of this research were to ascertain the current situation based on an ergonomic survey of workers who work in the mobile work-style, and to identify problems, and propose solutions.
Experiment participants and method: Our aim was to ascertain the current situation in offices by measuring satisfaction in terms of factors such as the comfort, fatigue, and ease-of-use of equipment and office furniture for people working in all workplace environments, not just conventional fixed offices. To achieve this, we prepared and administered questionnaires to 115 employees at two private companies which are especially committed to using the mobile work-style.
Results: Chairs and desks are found to influence the satisfaction by Structural Equation Modeling. The present survey found that the effects due to lighting/furniture and the satisfaction of network environment remarkably influenced the workers' satisfaction.
Conclusion: The current status of workers working in the mobile work-style was ascertained using a survey questionnaire. As a result, two points became clear. First, the physical environment in a company has a major impact on satisfaction. Second, is the inadequate understanding and low level of concern for ergonomics among workers. As a solution for the first, the possibilities are: (1) Improvement of worker satisfaction through proper layout/design and furniture/fixtures, (2) Improvement of work efficiency, such as the ability to concentrate and ease of viewing monitor screens through proper lighting, and improvement in peace-of-mind such as a sense of ease or pleasantness, and (3) improvement of satisfaction by developing the network environment and improving factors such as stress due to no assigned seats. A reduction in stress in office environments can be expected by adopting, as a measure to resolve the above two issues, company-wide education in the need for and awareness of using adjustment methods for chairs and other furniture, and equipment which is suited to the body.

Keywords: Mobile work-style, Office, Satisfaction
Count : 630
Basic study on improving sound localisation accuracy for musical tones by adding broadband noise
Publish Date : 2017/03/02  Vol.17
Authors : 
Hidenobu Takao*, Kanagawa Institute of Technology
Ryosuke Katayama, Kanagawa Institute of Technology
Report Outline : 
Purpose: When presenting a virtual auditory display (VAD) to a user who has difficulty using visual information, such as a visually impaired individual, an acoustic head related transfer function (HRTF) is necessary for vertical localisation. However, measurement of the HRTF is time consuming and costly. Because HRTFs differ between individuals, the use of another person’s HRTF reduces the accuracy of localisation. In this study, we propose and evaluate an extremely simple method for improving the accuracy of virtual sound localisation on the vertical plane using the same HRTF for various individuals, which may help with the use of a VAD.
Subjects and method: Six male university students (mean age of 22.5±2.5 years) with normal hearing and sight participated in the experiment, during which they wore blindfolds. Sound localisation accuracy was compared among three different conditions: presentation of a tone alone (tone condition), presentation of broadband noise alone (noise condition), and mixed presentation of a tone and broadband noise (mixed condition). Two types of playback system were used: a speaker array and virtual conditions (hearing binaurally through headphones). The stimuli were presented from a total of 13 different directions on the median plane at 10° intervals, from -60° (lower side) to 60° (upper side).
Results: As sound sources were presented farther from 0° in either direction, the target direction offset from 0° was more underestimated. It was found that in the virtual condition, the superimposition of musical tones and broadband noise significantly improved localisation accuracy compared with presenting each alone.
Conclusion: The present study demonstrated that when presenting virtual sound without personalising the HRTF, the extremely simple method of adding broadband noise markedly improves sound localisation accuracy on the vertical plane directly ahead of a subject.
Keywords: Virtual Auditory Display, Visual Impairment, Sound Localisation, 3D Sound, Binaural, Augmented Reality.
Count : 962
Evaluation of anatomical training for nursing students using unfixed lung, trachea, and larynx of swine
Publish Date : 2017/01/15  Vol.17
Authors : 
Masaaki TAKAYANAGI*, Department of Anatomy, Faculty of Medicine, Toho University,
Megumi SUGAHARA, Toho University Omori Medical Center
Manami NOZAKI, Dept of Fundamental Nursing, Faculty of Nursing, Toho University
Satomi KOBAYASHI, School of Nursing, Tokyo Eisei Gakuen College
Tomokazu KAWASHIMA, Department of Anatomy, Faculty of Medicine, Toho University
Hideo HOSHI, Department of Anatomy, Faculty of Medicine, Toho University
Tadanobu Chuyo KAMIJO, Department of Anatomy, Faculty of Medicine, Toho University
Fumi SATO, Department of Anatomy, Faculty of Medicine, Toho University
Report Outline : 
Objectives: Anatomy and physiology are fundamental subjects for establishing a foundation of knowledge for nursing. We have conducted anatomical training using unfixed respiratory internal organs (lung, trachea, and larynx) of swine in order to provide anatomy education to nursing students, since nursing students in Japan are not able to dissect the human body for learning. The objective of this study was to evaluate anatomical training of participating students and instructors, in order to inform development of an educational system effective at teaching anatomy of the respiratory system, and to enhance educational technique.
Subjects and methods:Grade 1 nursing students participated in an anatomy practicum using unfixed respiratory systems of swine (dissection, identification of the parts, labelling, measurement, and recording), after prior study of a textbook and distributed the manual for this anatomical training. We conducted a survey using a questionnaire with five-point Likert scale responses to investigate the benefit of the anatomical training among 425 nursing students who participated in the anatomy practicum. We also interviewed 5 instructors to evaluate the anatomical training.
Conclusions: The percentage of students who evaluated the anatomical training as meaningful were 95.4%, 94.1%, and 88.8% for lung, trachea, and larynx, respectively (average 92.8%). Our results suggest that the anatomical training was meaningful for learning anatomy among nursing students. In particular, many students were interested in the air injection demonstration using unfixed lung and segmental bronchus, where movement of the lung can be clearly observed, providing a strong learning opportunity. This demonstration is one of the most popular training experiences among the students. The demonstration enhances understanding of the concept of the pulmonary segmentation, shrinkage of the lung, and pneumothorax, as well as the dynamic image of change of the lung during respiration.
Keywords:Anatomical education, Nursing students, Respiratory system, Lung, Swine
Count : 839
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