• Journal of Korean Physical Therapy Science
• /
• v.11 no.3
• /
• pp.28-37
• /
• 2004

Background: Lumbar joint dysfunction is reported to be the main cause of lower back pain (LBP). The purpose of this study was to evaluate the effect of joint dysfunction on the postural balance of the lower hack and pelvis in different normal activities such as walking or stair management. Also it was studied whether the status of LBP (intensity and duration of LBP, length of treatment) contributes to die pelvic height difference (PHD) in various postures. Subjects: 28 patients with LBP and 32 normal adult volunteers, 60 years of age or younger, who came to the Community Health Center and orthopedic clinics in Incheon, South Korea. Methods: In order to determine the accuracy of the manual angulometer method in measuring the PHD, it was compared to the pelvic x-ray method in selected subjects. In the manual angulometer method, the arm of the angulometer was placed on the top of both iliac crests. The PHD was measured in static upright stance, then one-legged stance, on the affected leg or unaffected leg each time. Information regarding the disease status was obtained through interviews. Visual assessment scale was used to grade the intensity of LBP. Data analysis was performed using SPSS 10.0/PC program. Homogeneity between the two groups was tested by 2-test and t-test. To compare the PHD of the subgroups, we used t-test, F-test and two-way ANOVA. Relationships among dependent variables were analyzed by Pearson correlation analysis. Conclusion: In patients with LBP, lumbar joint dysfunction causes lumbar and pelvic postural asymmetry during normal activities.

• PNF and Movement
• /
• v.21 no.2
• /
• pp.243-253
• /
• 2023

Purpose: This study aimed to investigate the effects of an abdominal drawing-in maneuver (ADIM) with a light load while sitting on transverse abdominis contraction in subjects with and without low back pain. Methods: In this study, 20 participants with chronic low back pain and 20 controls participated. Ultrasonography was used to assess the thickness of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) muscles. Muscle thickness was measured at rest and during ADIM in three different sitting postures: (1) just sitting, (2) sitting loaded position (holding a 1 or 2 kg dumbbell in each hand), and (3) sitting loaded shoulder flexion position (holding a 1 or 2 kg dumbbell in each hand). Results: The contraction ratio (CR) and preferential activation ratio (PAR) of the TrA during ADIM had no significant interactional effect between the group and the sitting postures. However, the CR and PRA of the TrA during the ADIM showed significant differences among the three different sitting postures. The CR of the TrA during the ADIM in the sitting loaded shoulder flexion position was significantly increased compared to that in the sitting position (p<0.05). Moreover, the PRA of the TrA muscle during ADIM in sitting loaded and sitting loaded shoulder flexion positions was significantly higher than that in the sitting position (p<0.05). Conclusion: The findings suggest that ADIM in the sitting-loaded shoulder flexion position should be implemented to facilitate TrA activity.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.2
• /
• pp.349-356
• /
• 2011

Objective: The purpose of this study was to analyze the risk factors of the musculoskeletal workload of mid-old-age female caregivers by identifying work postures and subjective symptoms. Method: This study was carried out on a total of 206 subjects 206 mid-old-age caregivers(45~65 years old) from November 2009 to April 2010: 206 mid-old-age caregivers (45~65 years old) at the long-term hospital. A questionnaires survey on general factors and subjective symptoms of subjects was conducted. The risk factors of the musculoskeletal workload evaluation method is based on OWAS, RULA, REBA according to occupation properties. Results: The analysis of the rates of the subjective symptoms showed that 78.6% subjects experience low back pain. The analysis of the work type showed that transfer is the highest rate(36.3%) and position change is the second(18.2%). The analysis of the work postures showed that the thrusted back with twisting position over $20^{\circ}$ is highest rate(37.4%), the bended back forward with twisting position is the second(27.5%). Conclusion: This study suggested that the need of preventive education for caregivers and workload improve. It is hoped that subsequent study on the difference of subjective symptoms between educated caregivers and non educated caregivers will be conducted.

• Safety and Health at Work
• /
• v.8 no.2
• /
• pp.212-219
• /
• 2017

Background: Low back pain (LBP) is a major problem for office workers. Individuals adopting poor postures during prolonged sitting have a considerably increased risk of experiencing LBP. This study aimed to investigate seat pressure distribution characteristics, i.e., average pressure, peak pressure ratio, frequency of postural shift, and body perceived discomfort (BPD), during 1 hour of sitting among office workers with and without chronic LBP. Methods: Forty-six participants (chronic LBP = 23, control = 23) typed a standardized text passage at a computer work station for an hour. A seat pressure mat device was used to collect the seat pressure distribution data. Body discomfort was assessed using the Body Perceived Discomfort scale. Results: Office workers with chronic LBP sat significantly more asymmetrically than their healthy counterparts. During 1-hour sitting, all workers appeared to assume slumped sitting postures after 20 minutes of sitting. Healthy workers had significantly more frequent postural shifts than chronic LBP workers during prolonged sitting. Conclusion: Different sitting characteristics between healthy and chronic LBP participants during 1 hour of sitting were found, including symmetry of sitting posture and frequency of postural shift. Further research should examine the roles of these sitting characteristics on the development of LBP.

• Fashion & Textile Research Journal
• /
• v.26 no.1
• /
• pp.35-43
• /
• 2024

This study aimed to objectively classify the lateral torso posture types and functions of older women. We used 3D body scan data of 119 women aged 70-85 years from the 6th SizeKorea project. First, we defined three torso axes to represent the lateral torso posture types: posterior waist-back, back-cervical, and whole torso axes. Next, we asked experts to select one of four lateral torso posture types-stooped, straight, leaning back, and swayback postures-by looking at the lateral photographic data of 119 older women. To identify the axis that best represented each lateral torso posture type, a discriminant analysis was conducted using the angle of each of the three torso axes as an independent variable and an expert's visual classification as a dependent variable. Based on the analysis, the whole torso and backcervical axis angles were selected as variables for judging lateral torso posture types. Subsequently, we developed a classification function to determine which of the four lateral torso posture types of a particular participant was applicable for a new individual. The method developed in this study is significant in that it enables the objective classification of the lateral torso postures types of older women.

• Journal of the Korean Society of Safety
• /
• v.12 no.4
• /
• pp.209-213
• /
• 1997

Manual lifting techniques are commonly defined in terms of the postures adopted at the start of the lift. Quantitative definition is problematic, however, because the absolute joint angles adopted to lift an object are influenced by task parameters, such as the initial height of the load. The main objective of this study is to investigate the grip strength of the both hands at the initial lifting points. The survey is conducted by measuring the compression force, anthropometric data and grip strength at the lifting postures for the subjects(n=50) who is assigned to their job as usual. The experiment is peformed at the four lifting postures which involving the combination of two horizontal factors(H1 : 35 cm, H2 : 55 cm) and two vertical factors(V1 : 20~80 cm, V2 : 47~102 cm). The analysis result of lifting posture indicated that each H1-V1, H2-V1 combinations are about 60$^{\circ}$ and each H1-V2, H2-V2 combinations are about $30^{\circ}$. There are significant differences on grip strength between $60^{\circ}$ and $30^{\circ}$ stooped posture. The results of this study can be provided a method defining lifting postures at the minimum grip strength. Also, it is eliminated a hazard of the injuries which are cumulative trauma disorders(CTDs) and back pain, increased a productivity and improved a welfare of workers.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.647-650
• /
• 1996

Manual materials handling and improper working postures are known to be a major cause fo low back injuries, which are one of the major problems in the economic and public health aspects. In this study, two machine repair shops of a manufacturing company in Pohang are selected to investigate the potential hazards of low back injuries. Questionnaire study and worker's strength evaluation are conducted and the results are analyzed. Field workers performing the relatively low stressful jobs were also studied as a control group for comparison with the workers performing the tasks under study.

• Physical Therapy Korea
• /
• v.19 no.1
• /
• pp.1-9
• /
• 2012

The purpose of this study was to investigate the kinematic and kinetic changes that may occur in the pelvic and spine regions during cross-legged sitting postures. Experiments were performed on sixteen healthy subjects. Data were collected while the subject sat in 4 different sitting postures for 5 seconds: uncrossed sitting with both feet on the floor (Posture A), sitting while placing his right knee on the left knee (Posture B), sitting by placing right ankle on left knee (Posture C), and sitting by placing right ankle over the left ankle (Posture D). The order of the sitting posture was random. The sagittal plane angles (pelvic tilt, lumbar A-P curve, thoracic A-P curve) and the frontal plane angles (pelvic obliquity, lumber lateral curves, thoracic lateral curves) were obtained using VICON system with 6 cameras and analyzed with Nexus software. The pressure on each buttock was measured using Tekscan. Repeated one-way analysis of variance (ANOVA) was used to compare the angle and pressure across the four postures. The Bonferroni's post hoc test was used to determine the differences between upright trunk sitting and cross-legged postures. In sagittal plane, cross-legged sitting postures showed significantly greater kyphotic curves in lumbar and thoracic spine when compared uncrossed sitting posture. Also, pelvic posterior tilting was greater in cross-legged postures. In frontal plane, only height of the right pelvic was significantly higher in Posture B than in Posture A. Finally, in Posture B, the pressure on the right buttock area was greater than Posture A and, in Posture C, the pressure on the left buttock area was greater than Posture A. However, all dependent variables in both planes did not demonstrate any significant difference among the three cross-legged postures (p>.05). The findings suggest that asymmetric changes in the pelvic and spine region secondary to the prolonged cross-legged sitting postures may cause lower back pain and deformities in the spine structures.

• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.4
• /
• pp.413-423
• /
• 2001

Low back disorders (LBDs) are one of the most common and costly work-related musculoskeletal disorders. One of the major possible risk factors of LBDs is to work with static and awkward trunk postures, especially in a complex trunk posture involving flexion, twisting and lateral bending simultaneously. This study is to examine the effect of complex trunk postures on the postural stresses using a psychophysical method. Twelve healthy male students participated in an experiment, in which 29 different trunk postures were evaluated using the magnitude estimation method. The results showed that subjective discomfort significantly increased as the levels of trunk flexion, lateral bending and rotation increased. Significant interaction effects were found between rotation and lateral bending or flexion when the severe lateral bending or rotation were assumed, indicating that simultaneous occurrence of trunk flexion, lateral bending and rotation increases discomfort ratings synergistically. A postural workload evaluation scheme of trunk postures was proposed based on the angular deviation levels from the neutral position. Each trunk posture was assigned numerical stress index depending upon its discomfort rating, which was defined as the ratio of discomfort of a posture to that of its neutral posture. Four qualitative action categories for the stress index were also provided in order to enable practitioners to apply corrective actions appropriately. The proposed scheme is expected to be applied to several field areas for evaluating trunk postural stresses.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.1
• /
• pp.145-152
• /
• 2013

Objective: The aim of this study is to develop an ergonomic office chair that has an alarm function for the unbalanced sitting postures. Background: Contrary to expectation, it is reported that office workers sit on their chairs much more in unbalanced postures during daily work. Even though an office worker uses an ergonomically good-designed chair and begins their work in a good sitting posture, his/her posture is likely to shift to the unbalanced bad posture. Therefore, a posture alarm system would be very helpful in keeping office workers' good postures. Method: We developed a prototype chair with four load cells under a seat pan and one load cell beneath a backrest. Through some experiments, we set the criteria for unbalanced bad postures then implemented the criteria into the alarm system of the prototype chair. The chair called e-BASE chair could detect unbalance postures and show alarms for chair users. We also enhanced back support by developing a step-wised folding backrest. Results: The e-BASE chair showed better performance in interface pressure distributions and balanced posture ratio in VDT work. Conclusion: The ergonomic chair with posture alarm function(e-BASE chair) was developed. It showed better performance in seat pressure distribution and in keeping good posture during office work. Application: The posture alarm system and folding backrest can be applied to the new models of office chair.