• Journal of Biomedical Engineering Research
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• v.42 no.5
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• pp.225-231
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• 2021

The purpose of this study was to investigate the effect on the activity of the upper trapezius and erector spinae according to the length difference of the backpack using electromyogram (EMG). We also conducted a study comparing the center of pressure (COP) and weight distribution before and after using Wii® balance board. Thirty individuals were randomly assigned to the experimental group (n=14) wearing a backpack with a short right strap length and a control group (n=16) wearing a backpack with the same strap length. Data were collected by dividing into groups, carring a 15% weight backpack and walking for 20 minutes on a treadmill. As a result of analyzing the EMG data, there was no significant change in the upper extremity muscle activity of the control group, but it was significantly decreased in the right upper trapezius activity of the experimental group (p<0.05). In addition, there was a significant change of COP in the experimental group (p<0.05), but there was no significant difference of the weight distribution in both groups. Recognizing mechanical changes in the body that may occur due to the asymmetry of the strap length is thought to be helpful for systematic ergonomic intervention according to changes in the external environment in the future.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.766-774
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• 2022

In this study, the fit of commercial sports bras was analyzed according to various design variations, focusing on the shape of the shoulder strap, which is known to cause great discomfort in wearing sports bras. Experimental clothes were set to four commercially available sports bras with different shoulder strap shapes. The results showed that, in "size suitability," the overall satisfaction with experimental clothing B, of which the shoulder strap can be adjusted, was the highest, especially for "underbust circ. fit," "bust circ. Fit," and "shoulder strap length." In the "Shape suitability" and "Wearability" sections, experimental clothing B also showed the highest satisfaction and the shoulder strap adjustment device did not negatively affect wearing satisfaction. In the question on "side wings rolled up," experimental clothing A also received a relatively good score, which is due to its long front length. In the "Compression of the front center" section, the responses for experimental clothing A and B were "appropriate" and for C and D, they were "pressurized." In "motion suitability" as well, satisfaction with experimental clothing B was the highest, followed by experimental clothes A, C, and D. In the "body shape correction" section, clothing B elicited the highest satisfaction, followed by experimental clothes A, C, and D, in that order. Overall, it is recommended that shoulder straps be applied with adjustable straps for the comfort of the shoulder area while wearing sports bras.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.31-36
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• 2022

Objective: The purpose of this study was to investigate muscle activation according to the four strap lengths in the TRX plank exercise to provide scientific and accurate data on effective training methods. Method: Twenty healthy men who had at least 6 months of weight training experience and could fully adjusted plank exercise, were participate in this study (age: 25.2 ± 3.7 yrs., height: 174.2 ± 3.9 cm., weight: 71.2 ± 9 kg). To pursue the study purpose, surface electrodes were attached to trunk muscles (pectoralis major, rectus abdominis, external oblique, internal oblique, erector spinae, latissimus dorsi) and lower extramity muscles (gluteus maximus, rectus femoris, gastrocnemius), and the muscle activity was measured using 11-channel electromyography equipment. In order to verify the muscle activation according to the four strap lengths during TRX plank exercise, an one-way ANOVA with repeated measure was used with statistical significance level set at as α=.05. Results: First, there were statistically significant differences in pectoralis major, rectus abdominis, external oblique, internal oblique, and erector spinae among TRX strap lengths. Second, there were statistically significant differences in gluteus maximus, rectus femoris, and gastrocnemius among TRX strap lengths. Third, even though no statistically significant difference found in latissimus dorsi, but increased muscle activation tendency was showed as the length of the strap increased. Conclusion: From the results of this study, it may be possible that TRX exercise prevent injuries and improve lower extremity muscle as well as trunk muscles by setting appropriate length of strap.

• Journal of Korean Physical Therapy Science
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• v.22 no.2
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• pp.29-36
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• 2015

Purpose : the purpose of the study was to investigate the effect of craniovertebral angle on bag strap length change method : this study is aimed at twenties healthy adult for 30 persons (male-8, female-22) research participant attach marks on tragus and cervical7 participant did not carry bag in First test. thereafter we take a picture mark point and measure the angle. immediately the second experiment was designed to carry back on participant's iliac crest and to walk freely for five minutes. afterward, we take a picture mark point and measure the angle. last experiment was performed after five minutes break. participants carried back on 10cm below participant's iliac crest and third experiment was performed the same way. results : Increase the length of the bag, craniovertebral angle is reduced and there is a significant difference between the three experiments.(p=.000) conclusion : when hold the back too long, Cervical spine cause temporary head forward posture. so carry on bag short.

• Physical Therapy Korea
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• v.30 no.2
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• pp.110-119
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• 2023

Background: Osteoarthritis is a common condition with an increasing prevalence and is a common cause of disability. Osteoarthritic pain decreases the quality of life, and simple gait training is used to alleviate it. Knee osteoarthritis limits joint motion in the sagittal and lateral directions. Although many recent studies have activated orthotic research to increase knee joint stabilization, no study has used patellar tendon straps to treat knee osteoarthritis. Objects: This study aimed to determine the effects of patellar tendon straps on kinematic, mechanical, and electromyographic activation in patients with knee osteoarthritis. Methods: Patients with knee osteoarthritis were selected. After creating the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), leg length difference, Q-angle, and thumb side flexion angle of the foot were measured. Kinematic, kinetic, and muscle activation data during walking before and after wearing the orthosis were viewed. Results: After wearing the patellar tendon straps, hip adduction from the terminal stance phase, knee flexion from the terminal swing phase, and ankle plantar flexion angle increased during the pre-swing and initial swing phases. The cadence of spatiotemporal parameters and velocity increased, and step time, stride time, and foot force duration decreased. Conclusion: Based on the results of this study, the increase in plantar flexion after strap wearing is inferred by an increase due to neurological mechanisms, and adduction at the hip joint is inferred by an increase in adduction due to increased velocity. The increase in cadence and velocity and the decrease in gait speed and foot pressure duration may be due to joint stabilization. It can be inferred that joint stabilization is increased by wearing knee straps. Thus, wearing a patellar tendon strap during gait in patients with knee osteoarthritis influences kinematic changes in the sagittal plane of the joint.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.4
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• pp.431-443
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• 2007

Statement of problem: Injuries along with discomfort may result on the oral mucosa when non-rigid material is used as the major connector in construction of RPD, since nonrigid major connectors transmit unstable forces throughout the appliance. Titanium which recently draws attention as a substitute of Co-Cr had a difficulty in fabricating due to high melting temperature but the development of casting technique makes it possible to apply to the clinical case. Purpose: The purpose of this study was to investigate the rigidity and the castability of titanium upper major connector by design and make a comparison with Co-Cr major connectors which are widely used in clinical cases now. Material and methods: Casting was done using CP-Ti(Grage 2) (Kobe still Co., Japan) for the experimental groups, and 4 various designs namely palatal strap, U-shaped bar, A-P strap, and complete palatal plate were casted and 5 of each designs were included in each group. For the experimental group, Universal testing machine (Model 4502; Instron, Canton, Mass) was used to apply vertical torsional force vertically to the horizontal plane of major connector. In the second experiment, Vertical compressive force was applied to the horizontal plane of major connector. As a comparative group, Co-Cr major connector was equally manufactured and underwent the same experimental procedures Strain rate was measured after constant loading for one minute duration, and statistical analysis was done with SPSS ver.10.0 for WIN(SPSS. Inc. USA). From the one-way ANOVA and variance analysis (P=0.05), Scheffe's multiple comparison test implemented. Results: 1. Least amount of strain was observed with complete palatal plate followed by A-P bar, palatal bar, and the U-shaped bar having most amount of strain. 2. In all designs of titanium major connector, less strain rate was observed under compressive loading than under torsional loading showing more resistance to lateral force. 3. For titanium major connector, less strain rate was observed when the force is applied to the first premolar area rather than to the second molar area indicating more strength with shorter length of lever. 4. In Comparison of Co-Cr major connector with titanium major connector, palatal strap and U-shaped bar designs showed higher strength under torsional force that is statically significant, and under compressive force, no significant difference was observed expert for U-shaped bar. 5. In titanium major connector, complete palatal plate showed lowest success rate in casting when compared with the Co-Cr major connector. Conclusion: Above results prove that when using titanium for major connector, only with designs capable of generating rigidity can the major connector have almost equal amount of rigidity as Co-Cr major connector and show lower success rate in casting when compared with the Co-Cr major connector.