• Korean Journal of Applied Biomechanics
• /
• v.31 no.2
• /
• pp.104-112
• /
• 2021

Objective: This study aimed to analyze the effects of consecutive whole body vibration through heel raise posture on the center of pressure and electromyography of anterior tibial muscle, lateral gastrocnemius and soleus muscles during single-leg stance. Method: The subjects of this study included 30 healthy males in their 20's, with the following inclusion criteria: no history of orthopaedic medical history, no participation in regular exercises, no history of whole body vibration exercise, and right leg being the dominant leg. The experimental procedure involved pretreatment measurement of eye open single-leg stance, application of whole body vibration for 30 seconds, post-treatment measurement (3 measurements in total). Static and dynamic movements have been measured over 2 separate experiments, with 72 hours gap between the experiments. Static movement involved maintaining single-leg heel raise posture for 30 seconds while applying whole body vibration, and dynamic movement involved heel raise (15 repetitions over 30 seconds) while applying whole body vibration. The strength of applied whole body vibration was 35 Hz frequency and 2~4 mm amplitude. Results: As the single-leg posture after static heel raise posture, mediolateral velocity of the center of pressure at post 2 and post 3 were significantly reduced compared to the pre-treatment measurement. In addition, the percentage for reference voluntary contraction in anterior tibial muscle and soleus and median frequency at anterior tibial muscle and lateral gastrocnemius muscle at post 3 were significantly decreased compared to the pre-treatment value. As the single-leg posture after dynamic heel raise posture, the mediolateral 95% edge frequency of the center of pressure and median frequency at anterior tibial muscle, lateral gastrocnemius muscle, and soleus muscle at post 3 were significantly reduced compared to the pre-treatment value. Conclusion: Acute whole body vibration via static and dynamic heel raise posture have positive effect on mediolateral posture control during single-leg stance.

• Journal of Korean Medicine Rehabilitation
• /
• v.30 no.2
• /
• pp.125-137
• /
• 2020

Objectives The purpose of this study was to examine how changes in the cervical spine correlate with body posture changes in the whole body, and to find out the significance of complementary clinical application X-ray and Chuna posture analysis. Methods From January 1, 2019 to October 31, 2019, the results of 27 patients with pain in the vertebral region were analysed in accordance with the results of cervical X-ray and Chuna posture analysis. In order to confirm the significance of Chuna posture analysis results, the survey of 187 Chuna standard curriculum instruction qualification certifiers was conducted and the responses of 47 of them were analyzed. Results The occiput-atlas cline angle increases in both hypolordosis/hyperlordosis groups based on cervical lordosis angle, and increases further than in the hyperlordosis group. There were significant correlations between the changes in the cervical spine and the body posture changes in the whole body. There were no significant differences between cervical X-ray sagittal parameters and the body posture analysis parameters based on the patient's major disease codes. Conclusions As a result of conducting a survey on the clinical importance of the body posture analysis parameters, the importance of cervical parameters was verified. Changes in the cervical spine may not only cause other changes in the cervical region, but also affect the body posture changes in the whole body. The complementary application of X-ray and Chuna posture analysis results is helpful in clinical diagnosis and treatment of musculoskeletal disorders.

• Journal of Korean Institute of Industrial Engineers
• /
• v.28 no.2
• /
• pp.216-222
• /
• 2002

The ergonomic human model can be considered as a tool for the evaluation of ergonomic factors in vehicle design process. The proper anthropometric data on driver's postures are needed in order to apply a human model to vehicle design. Although studies on driver's posture have been carried out for the last few decades, there are still some problems for the posture data to be applied directly to the human model due to the lack of fitness because such studies were not carried out under the conditions for the human model application. In the traditional researches, the joint angles were evaluated by the categorized data, which are not appropriate for the human model application because it is so extensive that it can not explain the posture evaluation data in detail. And the human models require whole-body posture evaluation data rather than joint evaluation data. In this study a postural evaluation function was developed not by category data but by the concept of the loss function in quality engineering. The loss was defined as the discomfort in driver's posture and measured by the magnitude estimation technique in the experiment using a seating buck. Four loss functions for the each joint - knee, hip, shoulder, and elbow were developed and a whole-body postural evaluation function was constructed by the regression analysis using these loss functions as independent factors. The developed postural evaluation function shows a good prediction power for the driver's posture discomfort in validation test. It is expected that the driver's postural evaluation function based on the loss function can be used in the human model application to the vehicle design process.

• International Journal of Safety
• /
• v.10 no.1
• /
• pp.32-35
• /
• 2011

Lifting capacity and difficulty of task are influenced by body posture. In RULA and REBA, the body was divided into segments which formed two groups, A and B. Group A includes the upper and lower arm and wrist while group B includes the neck, trunk and legs. This ensures that whole body posture is recorded so that any awkward or constrained posture of the legs, trunk or neck which might influence the posture of the upper limb. This study aimed to measure MVC (maximum voluntary contraction) and subjective judgment in psychophysical method (Borg's scale) according to trunk and upper arm angle and to analyze results statistically. The results of this study were that lifting capacity was more influenced by interaction of body posture rather than angles of each part, and MVC variation according to trunk and upper arms angles should different patterns. This means that we consider the interaction of trunk angles and upper arm angles when we access risk factors of the postures. This survey would be also the basic data to evaluate difficulty of lifting tasks according to body postures ergonomically.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.7 no.1
• /
• pp.87-98
• /
• 1997

In this study, subway train vibration has been measured to characterize the whole body vibration of Seoul subway lines for various human postures. Results show that the floor vibration level of the subway trains in the vertical direction is higher than that in other directions. At the standing human posture, vibration level of the head in the right-left direction are increased while that in the vertical direction is decreased. It is assumed that the different flexibility of the human body and the rolling motion of the subway trains are the main cause. At the sitting posture with back seat on, vibration level in the right and left direction at the human ischial tuberosities is lower than that in other directions. Results also show that there were little difference between back-seat on model and back-seat off model. Transmissibility analysis shows how the subway vibration affects the response of a human body.

• Journal of Korean Physical Therapy Science
• /
• v.30 no.1
• /
• pp.72-84
• /
• 2023

Background: The purpose of this study was to investigate the effect of whole-body vibration stimulation training on the thickness of the transversus abdominis muscle and the balance of sitting posture in children with spastic cerebral palsy. Design: Single-subject design(A-B-A-B). Methods: The subjects of this study were 9 children with spastic cerebral palsy. The study period was 12 weeks in total, and the baseline period and the intervention period were each assigned 3 weeks. Intervention was conducted twice a week for 30 minutes. During the baseline period, trunk stabilization exercise was performed, and during the intervention period, trunk stabilization exercise and whole-body vibration stimulation training were performed. Measurements were carried out at before the experiment, baseline 1, intervention 1, baseline 2, intervention 2 and the total number of measurements was 5 times. Repeated ANOVA was performed to compare the effects of exercise according to the intervention method. Results: The thickness of the transversus abdominis muscle and the balance of the sitting posture were statistically significantly increased compared to the baseline during whole-body vibration stimulation training (p<.05). Conclusion: Therefore, it was confirmed that whole-body vibration stimulation training improved the thickness of the transversus abdominis muscle in children with spastic cerebral palsy and was an effective intervention method for improving sitting posture balance.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.10a
• /
• pp.656-660
• /
• 2009

Various dynamic models of seated posture human body have been developed because the importance about the ride comfort assessment of vehicles is highly emphasized from day to day. The dynamic models of human body make possible the simulation of ride comfort assessment by applied to the vehicle dynamic model. Recently, the importance of ride comfort is also regarded to working vehicles such as excavators and the research of the ride comfort assessment for working vehicle is required. Only vertical vibration dominantly occurs on the seat of the private car driving with constant velocity. In contrast, vertical/fore-and-aft/pitch vibration seriously occurs on the seat of the working excavator. So, the dynamic models of seated human body applied to working vehicles should describe the dynamic characteristics for vertical/fore-and-aft/pitch direction. In this paper, the dynamic characteristics of seated human body are represented as apparent inertia matrix. The apparent inertia matrix is obtained by the vertical/fore-and-aft/pitch excitation of seated human body. 6 resonance frequencies are observed in apparent inertia matrix. This result can be applied to develop the dynamic model for seated posture human body.

• Journal of the Korea Convergence Society
• /
• v.9 no.10
• /
• pp.371-376
• /
• 2018

The purpose of this study is to clarify the effects of whole-body vibration and to provide scientific basis for effective exercise by analyzing the differences in lower extremity muscle activation according to squat position during whole body vibration. In this study, muscle activation during whole-body vibration was measured in 10 healthy males in their 20s with no orthopedic conditions during standing posture, deep squat, half squat, and heel raise squat. Muscle activation was compared by measuring the root mean square (RMS) with electromyography electrodes attached to lateral gastrocnemius, tibialis anterior, vastus lateralis, and biceps femoris. The vibration intensity was applied in combinations of the volumes of 50 and 80 and the frequencies of 10, 25, and 40 Hz in each posture. The results showed that there were differences in muscle activations of external gastrocnemius, tibialis anterior, and vastus lateralis among the position(p<.05). The heal raise squat was found to have a high muscle activation effect.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.241-245
• /
• 2003

When considering the effects of whole-body vertical vibration, it is valuable to have an understanding of the mechanical characteristics (mechanical impedance and apparent mass) of the body. This paper addresses experimental results carried out to investigate the characteristics of apparent masses fer 41 Korean. The apparent masses of the seated human body in vertical direction were measured during different experimental conditions, such as vibration excitation level (0.5-2 ms$\^$-2/ r.m.s). frequency range (1-50Hz), and upper body posture (relaxed, normal and backrest-upright). We showed the average of all subjects and all conditions and compared the results with ISO5982/DIS (2000).