• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.59-63
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• 2021

Objective: Through comparative analysis of muscle activity for whole-body vibration, walking and running movements, it is to verify the training effect of whole-body vibration exercise in terms of amount of exercise and muscle activity characteristics. Method: Flat ground walking and slope walking (10 degrees) at a speed of 5 km/h, flat ground running and slope running (10 degrees) at a speed of 11 km/h for running were performed on treadmill, and squats were maintained at 12 Hz, 20 Hz, and 29 Hz conditions on Whole body vibration exercise equipment (Galileo). Muscle activity was analyzed through EMG analysis device for one minute for each condition. Results: The Anterior Tibialis and Erector Spinae show greater exercise effect in whole-body vibration than walking and running. The Rectus Femoris, Biceps Femoris, and Gluteus Maximus have the best effect of exercise in flat running. Whole-body vibration exercise showed greater muscle activation effect as the frequency increased, and exercise effect similar to walking during the same exercise time. Conclusion: The amount of exercise through Whole-body vibration exercise was similar to that of walking exercise, and the Anterior Tibialis and Erector Spinae shows better exercise effect than walking and running.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.1
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• pp.31-35
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• 2004

The incidence of in-line skating injuries has increased with the rapid growth in the sport's popularity. The purpose of this article is to describing the type of the inline skating and document basic skills, protective equipment use, identify contributing or precipitating factors associated with injuries. Loss of control and inexperience were factors contributing to the injuries. Also protective equipment among skaters was underused. In conclusion, the safety education program for inline skating, optimal design and efficacy of protective equipment should identify with further study.

• Advances in nano research
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• v.14 no.3
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• pp.273-284
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• 2023

Combating the worldwide environmental threat of plastic waste pollution has become a priority. Plastic pollution has the potential to impact land, rivers, and seas, since many marine and terrestrial organisms have perished as a result of plastic's non-biodegradability and soil dangers. For this consumption, it seems required to manufacture and use new renewable resources. Renewable materials for diverse applications have been created utilizing nanotechnology, which may replace conventional materials for children's activities and sports equipment. This study investigates and suggests that nanotechnology-based materials be replaced with conventional materials to save the environment in manufacturing equipment for children's physical activities. On the basis of the mechanical sciences, a stability study of the bending behavior of small-scale structures will be performed for the various recommended materials.

• Geomechanics and Engineering
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• v.32 no.5
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• pp.463-474
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• 2023

Materials produced with the help of new technology are used in the design of materials used in all science and engineering departments today. A sports engineering and sports equipment department is one of these departments. The use of nanotechnology in sports equipment is one of the most popular uses of this technology today. Nanomaterials have been used in sports equipment for many years, and reputable companies have benefited. Athletes' equipment allows them to display their skills to the fullest extent. It has always been a dream of professional athletes and their coaches to have unique equipment. As a result, engineers have spent all their time and effort solving this problem. Science and engineering can do various things to meet the needs of all sports levels, including specific and detailed designs, the use of appropriate materials, and standardization tests on equipment. However, these aspects must remain aligned with the latest technologies as they develop, just as with other sciences. These technologies, especially nanotechnology, are essential to sports equipment and devices developed today by sports engineers. This article examines the balls that use nanotechnology and can also improve the athlete's performance by using this technology in a specific structure. Using nanotechnology to make nanocomposite poly-hope balls, which makes them lighter and more acceptable, reduces the impact on the ball and increases its movement speed.

• Korean Journal of Applied Biomechanics
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• v.26 no.2
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• pp.229-236
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• 2016

Objective: This study aimed, first, to develop core strength training equipment with elderly-friendly, easy-to-use features and, second, to investigate the effect of core strength training using the equipment on the performance and stability of the elderly in activities of daily living. Method: In this study, we developed training equipment with a stability ball that can be used for performing core strength exercises in the elderly. Twenty-three elderly subjects (age: $77.87{\pm}6.95years$, height: $149.78{\pm}6.95cm$, and weight: $60.57{\pm}7.21kg$) participated in this study. The subjects performed the core strength training exercise with 16 repetitions for 8 weeks (2 repetitions per week). Performance in activities of daily living was assessed by using the Short Physical Performance Battery (SPPB), a test of going up and down 4 stairs, and one-leg static balance test. Stability was quantified as changes in the center of pressure (COP) and C90 area. Results: With the core strength equipment, trunk core strength exercise could be performed by pulling or pushing a rope with 2 hands on the stability ball. During the task, the tension in the rope was manipulated by a motor connected to the rope and the COP of the subject was measured by 4 load cells mounted in the equipment. Our results showed that the SPPB score was significantly higher (p < .05), the time to complete the "going up and down 4 stairs" test was significantly shorter (p < .05), and one-leg static balance statistically improved under an eyes-open condition (p < .05) after as compared with before the core strength training. The changes in the COP in the anteroposterior and mediolateral directions, and C90 area were significantly lower in the posttest (p <. 05) than in the pretest. Conclusion: The core strength training exercise using the equipment developed in the present study improved the performance and stability of the elderly in activities of daily living.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.111-119
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• 2014

The purpose of this study was to investigate the effects of localized muscle fatigue and whole body fatigue on postural control during single-leg stance after impairment induced by heel raise and the Harvard step test. Thirty-eight university students (19 men: age, $20.1{\pm}0.2$ yrs; height, $175.0{\pm}5.23cm$; weight, $66.8{\pm}5.6kg$; body mass index, $21.8{\pm}1.7kg/m^2$, 19 women: age, $20.6{\pm}1.1yrs$ ; height, $163.6{\pm}6.7cm$; weight, $58.8{\pm}4.6kg$; body mass index, $22.0{\pm}2.2kg/m^2$) were participated in this study. Subjects performed a series of single-leg postural tasks prior to, following, and 24 hours after completing: heel raise or the Harvard step test. This study showed that the root mean squared distance and velocity in the anteroposterior and mediolateral planes of the center of pressure decreased significantly due to heel raise exercise-induced fatigue. Furthermore, the root mean squared distance in the anteroposterior and mediolateral planes, and the 95% confidence ellipse area of the center of pressure also decreased significantly 24 hours after completing the Harvard step test. In conclusion, this study showed that both heel raise exercise- and Harvard step exercise-induced fatigue affects postural control during single-leg stance in AP and ML planes. Furthermore, this study suggests that changes in the postural control strategy may have occurred after the fatigue protocols during single-leg stance. Also vision can attenuate the postural deficits associated with the fatigues. In order to clarify these results, further studies using other equipment and variables are necessary.

• 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.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.213-218
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• 2018

Objective: The purpose of this study was to examine the effect of the core muscle strength enhancement of the elderly on 8 weeks training using the core exercise equipment for the elderly on the ability to control the whole-body center of mass in posture stabilization. Method: 16 females (10 exercise group, 6 control group) participated in this study. Exercise group took part in the core strength training program for 8 weeks with total of 16 repetitions (2 repetitions per week) using a training device. External perturbation during standing as pulling force applied at the pelvic level in the anterior direction was provided to the subject. In a UCM model, the controller selects within the space of elemental variables a subspace (a manifold, UCM) corresponding to a value of a performance variable that needs to be stabilized. In the present study, we were interested in how movements of the individual segment center of mass (elemental variables) affect the whole-body center of mass (the performance variable) during balance control. Results: At the variance of task-irrelevant space, there was significant $test^*$ group interactions ($F_{1,16}=7.482$, p<.05). However, there were no significant main effect of the test ($F_{1,16}=.899$, p>.05) and group ($F_{1,16}=1.039$, p>.05). At the variance of task-relevant space, there was significant $test^*$ group interactions ($F_{1,16}=7.382$, p<.05). However, there were no significant main effect of the test ($F_{1,16}=.754$, p>.05) and group ($F_{1,16}=1.106$, p>.05). Conclusion: The results of this study showed that the 8 weeks training through the core training equipment for the elderly showed a significant decrease in the $Vcm_{TIR}$ and $Vcm_{TR}$. This result indicates that the core strength training affects the trunk stiffness control strategy to maintain balance in the standing position by minimizing total variability of individual segment CMs.

• The Korean Journal of Franchise Management
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• v.5 no.2
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• pp.69-79
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• 2014

This study was carried out to demonstrate how realistic any action that causes the selection criteria for new members to join the decisions of the general public about the growing recreational sport of golf to the present day. Looking at the results of in-depth interviews, "time out through direct participation "" become more and more expensive equipment "," varied program "," located near "," are items of personal development and interpersonal relationships "was found to have a significant impact on the public choice of leisure sports. It was with the greatest response in the dual to "become more and more expensive equipment," "self-development and personal relationships." These results exigent there in living the contemporary social phenomena that can not ignore the economic aspects of choosing a leisure sport and personal development and interpersonal relationships in organizations improve social promotion and sales, a key role in providing opportunities for upward mobility suggests that the passage is.

• Geomechanics and Engineering
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• v.35 no.5
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• pp.465-473
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• 2023

The higher order shear deformable model and an exact analytical method is used for analytical bending analysis of a cylindrical shell subjected to mechanical loads, in this work. The shell is modelled using sinusoidal bivariate shear strain theory, and the static governing equations are derived using changes in virtual work. The eigenvalue-eigenvector method is used to exactly solve the governing equations for a constrained cylindrical shell The proposed kinematic relation decomposes the radial displacement into bending, shearing and stretching functions. The main advantage of the method presented in this work is the study of the effect of clamping constraints on the local stresses at the ends. Stress, strain, and deformation analysis of shells through thickness and length.