• The Journal of Korean Physical Therapy
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• v.34 no.6
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• pp.312-316
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• 2022

Purpose: The purpose of this study was to investigate the effect of a kettlebell complex program according to the support surface on the lower extremity muscle activity and balance of baseball players. Methods: The participants were divided into two groups; unstable support surface group 1 (11 people) performed the kettlebell complex program on an unstable support surface, and stable support surface group 2 (10 people) performed the kettlebell complex program on a stable support surface. Muscle activity was measured by surface electromyography. Dynamic balance was measured with a balance-measuring equipment. A paired t-test was used to compare groups before and after the experiment. An independent t-test was performed to determine the difference in the degree of change between the two groups before and after the experiment. Results: The intragroup comparison between stable support surface group 1 and 2 showed significant differences in muscle activity and sense of balance. In the comparison between the groups, the difference in muscle activity in unstable support surface group1 was significant in the biceps femoris and rectus femoris muscles, and significant differences were also found in the sense of balance. Conclusion: These results suggest that a kettlebell exercise on an unstable support surface is more effective in improving muscle activity and sense of balance than a kettlebell exercise on a stable support surface.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.13-18
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• 2012

We investigated the cell activity of controlled titanium surface using various grinding methods including ELID (Electrolytic In-Process Dressing) grinding method. The influence of titanium surface condition by each grinding process on the cell activity was evaluated by ALP activity of MSC(Mesenchymal Stem Cells). The ALP activity of controlled surface by ELID grinding process using # 2000 wheel was higher than that of other titanium surface. The morphological, chemical properties of machined surface by grinding method was observed using various analytical method.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.132-132
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• 2013

Colloidal synthesis of nanoparticles with well-controlled size, shape, and composition, together with development of in situ surface science characterization tools, such as ambient pressure X-ray photoelectron spectroscopy (APXPS), has brought new opportunities to unravel the surface structure of working catalysts. Recent studies suggest that surface oxides on transition metal nanoparticles play an important role in determining the catalytic activity of CO oxidation. In this talk, I will outline the recent studies on the influence of surface oxides on Rh, Pt, Ru and Co nanoparticles on the catalytic activity of CO oxidation [1-3]. Transition metal nanoparticle model catalysts were synthesized in the presence of poly(vinyl pyrrolidone) polymer capping agent and deposited onto a flat Si support as two-dimensional arrays using the Langmuir-Blodgett deposition technique. APXPS studies exhibited the reversible formation of surface oxides during oxidizing, reducing, and CO oxidation reaction [4]. General trend is that the smaller nanoparticles exhibit the thicker surface oxides, while the bigger ones have the thin oxide layers. Combined with the nature of surface oxides, this trend leads to the different size dependences of catalytic activity. Such in situ observations of metal nanoparticles are useful in identifying the active state of the catalysts during use and, hence, may allow for rational catalyst designs for practical applications. I will also show that the surface oxide can be engineered by using the simple surface treatment such as UV-ozone techniques, which results in changing the catalytic activity [5]. The results suggest an intriguing way to tune catalytic activity via engineering of the nanoscale surface oxide.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.4
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• pp.75-83
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• 2013

Purpose : This research was conducted to see the correlation between sway speed and muscle activity for lower extremity of stroke patients through unstable surface training. Methods : A total of 60 patients were randomly divided unstable surface group (30 peoples) and stable surface group (30 people). Then they were asked to carry out the same exercise program for 6 weeks. The unstable surface group and stable surface group performed the exercise program on the balance mat and on the hard wood block. We checked the changes of sway speed and the changes in muscle activity for lower extremity. Results : The unstable surface group displayed significantly reduced sway speed, and improved muscle activity of lower extremity. There were significant correlation between change amount of muscle activity and sway velocity in Gastrocnemius, Biceps femoris during unstable surface training(r=.373, p<.05)(r=.369, p<.05). And there were not show significant differences during stable surface training. Conclusion : Judging from this, we can have knowledge that the correlation between increase of muscle activity and decrease of sway velocity for Gastrocnemius, Biceps femoris in the unstable surface training.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.3
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• pp.251-258
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• 2012

Purpose : The purpose of this study is to provide an efficient and basis for muscle activity of Quadriceps muscles and balance in anterior cruciate ligament reconstruction patients through unstable surface exercise and stable surface exercise. Methods : This study included 30 anterior cruciate ligament reconstruction patients belonging to A hospital and D orthopedic surgery clinic of province who attended the program for 30 minutes at a time and three times a week for 4 weeks. Of these 15 attended the unstable surface exercise program and 15 the stable surface exercise program. To increase muscle activity (%MVIC) and balance (WPL), the unstable surface exercise. Results : The %MVIC of lower extrmity muscle(RF, VL, VM) increased from before training to after training in the case of the participants who performed the unstable surface exercise, and the whole path length (WPL) decreased from before the training to after the training(p<.05). Conclusion : In conclusion, unstable surface exercise program helps to improve the balancing ability and musle activity in a anterior cruciate ligament recunstruction patients who requires both muscle activity and balance than stable surface exercise program.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.109-116
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• 1976

The effects of atelectasis on surface activity of lung extracts were examined in rabbits. Experimental atelectasis was produced in rabbits by artificial pneumothorax and surface tension properties were measured on saline extracts of lung 24 hrs, 48 hrs, one week and four weeks after the induction of pneumothorax. The results were as follows; 1) The minimum surface tension of excised lung extracts 24 hrs after pneumothorax was significantly increased to 28.3 0.41 dynes/cm, and the stability index was significantly decreased to 0.30 from normal value of 0. 87. 2) In the group which was re-expanded 24 hours, later from pneumothorax the surface activity was returned to almost normal range 24 hrs after reexpansion of collapsed lung, 3) When the atelectasis was continued by mechanical means, the extracts of atelectatic lung showed progressive decrease in surface activity, but it was found that surface activity returned to normal level after four weeks even the presence of atelectasis. 4) These observations suggest to us that atelectasis per se does not cause an increase in surface tension of lung extracts, and even in prolonged atelectasis the re-expansion of collapsed lung may be possible when the mechanical cause of atelectasis was excluded.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.579-584
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• 2022

Objective: To identify the effect of unstable surface kettlebell exercises on muscle activity and balance in middle and high school baseball players. Design: Randomized controlled trial. Methods: The participants were 29 middle and high school baseball players (Unstable surface kettlebell exercises group, USKE: 15; Stable surface kettlebell exercise group, SSKE: 14). The players in the USKE group performed kettlebell exercises for 60 mins on a stable surface thrice a week for 6 weeks, and the return rack was solidified on a stable surface in the same way as the experimental group. Before and after the experiment, the participant's muscle activity of the tibialis anterior and soleus was measured. In addition, the participant's balance was evaluated by measuring the distance moved from the foot's center of pressure (COP). The paired t-test was used to compare groups before and after the experiment. The independent t-test was conducted to assess differences in the degree of change between the two groups before and after the experiment. Results: Compared to the SSKE group, the USKE group showed significant differences in the muscle activity of the tibialis anterior and soleus and the balance with the eyes open and closed. Conclusions: The players in the USKE group showed a significant difference in muscle activity and balance than in those in the SSKE group. Thus, effectively including an unstable surface in the kettlebell exercise program will help improve physical function in athletes and people with musculoskeletal disorders.

• The Journal of Korean Physical Therapy
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• v.24 no.5
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• pp.300-305
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• 2012

Purpose: This study examined the muscle activity of the trunk muscles during weight shifting exercises on a stable and unstable surface. Methods: Ten healthy young subjects (4 males, 6 females) with no medical history of lower-extremity or lumbar spine disease were enrolled in this study. The muscle activity was recorded using surface electromyography (EMG) electrodes from the both sides of the external obliques and erector spinae muscles. Results: The EMG activities of the both rectus abdominalis, both external obliques and erector spinae muscles were significantly higher when the weight shifting exercise was performed on a firm surface than when a balance pad with a balance ball was used. In weight shifting exercises, the EMG activity of the contralateral external obliques and erector spinae muscles was significantly higher than that of the ipsilateral external obliques and erector spinae muscles under all three support surface conditions. Conclusion: Performing weight shifting exercise using an unstable surface is a useful method for facilitating the trunk-muscle strength and trunk stability.

• PNF and Movement
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• v.16 no.3
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• pp.433-439
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• 2018

Purpose: Visual information is one of the most important factors for postural balance. The purpose of this study was to investigate the effect of visual deprivation on the lower extremities and trunk muscle activity on an unstable surface during quiet standing. Methods: Fifteen healthy males from a university population participated in this study. Surface electromyography of the rectus abdominis, the erector spinalis, the vastus femoris oblique, the semitendinosis, the tibialis anterior, and the medial gastrocnemius was measured using EMG equipment (Telemyo 2400, Noraxon, USA). The participants were asked to maintain postural balance on an unstable surface (Balance pad, Airex, USA) for 30 seconds with eyes open and with eyes closed during quiet standing. The Wilcoxon test was used to compare the muscle activity of the lower extremities and the trunk between open and closed eyes on an unstable surface. Results: The muscle activity of the trunk and the lower extremities was increased more with eyes closed than with eyes open on the unstable surface during quiet standing. Conclusion: The findings from this study suggest that visual information could alter lower extremity and trunk muscle activity. Therefore, visual deprivation can be used as a method to improve postural balance.

• The Journal of Korean Physical Therapy
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• v.23 no.2
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• pp.7-15
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• 2011

Purpose: We investigated the relationship between the muscle activity and kinematic variables of the upper extremity during a push-up task on stable and unstable surfaces. Methods: We recruited 15 healthy subjects. Subjects completed the push-up task on stable and unstable surfaces. Surface electromyograms were recorded from the serratus anterior, upper trapezius, latissimus dorsi, infraspinatus to monitor changes in muscle activity. Markers for kinematic changes of elbow flexion, shoulder extension, shoulder retraction and scapular adduction were attached at C7, the T7 spinous process, both acromions, the scapula superior and inferior angle, the humerus lateral epicondyle, and the ulnar styloid process. Correlation coefficients between muscle activity and kinematic variables were analyzed by SPSS for Windows, version 15.0. Results: On the unstable surface, elbow flexion and shoulder extension increased with increasing muscle activity of serratus anterior, upper trapezius and infraspinatus. On the stable surface, shoulder retraction decreased with increasing muscle activity of serratus anterior and infraspinatus. Scapular adduction decreased with all types of increasing muscle activity, regardless of the support surface. Conclusion: Correlations between muscle activity and kinematic variables were observed on stable and unstable surfaces during a push-up task, while correlations between right and left variables were not clear. These finding suggest that it may be used to develop a rehabilitation program which could be effective in improving shoulder function in patients with shoulder problems.