• The Journal of Korean Physical Therapy
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• 제28권2호
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• pp.65-70
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• 2016

Purpose: The aim of this study was to determine the effects of electromyographic (EMG)-Biofeedback using closed kinetic chain exercise (EB-CKCE) on quadriceps angle (Q-angle) and quadriceps muscle activation and muscle activation ratio in subjects with patellofemoral pain syndrome and to provide fundamental information on rehabilitation exercise in patellofemoral pain syndrome. Methods: Thirty participants who met the criteria were included. The subjects were randomly divided into three groups: control group (Group I, n=10), semi-squat exercise group (Group II, n=10), and EMG-Biofeedback using closed kinetic chain exercise group (Group III, n=10). Intervention was provided to each group for eight weeks (three times per week; 30 minutes per day). Subjects were measured on Q-angle and quadriceps muscle activation. Results: Significant difference in Q-angle and quadriceps muscle activation was observed in groups II and III compared with control group I (p<0.01). Results of post-hoc analysis showed a significant difference in Q-angle and quadriceps muscle activation in on group III compared with groups I and II. Conclusion: Findings of this study suggest that closed kinetic chain exercise using EMG-Biofeedback that provides real-time biofeedback information on muscle contraction may have a beneficial effect on improvement of Q-angle and quadriceps muscle activation in patellofemoral pain syndrome.

• Carbon letters
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• 제2권3_4호
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• pp.176-181
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• 2001

A series of activated carbons were prepared from coconut shells and coal-tar pitch binder by physical activation with steam in this study. The effect of variable processes such as activation temperature, activation time and ratio of mixing was investigated for optimizing those preparation parameters. The activation processes were carried out continuously. The nitrogen adsorption isotherms at 77 K on pellet-shaped activated carbons show the same trend of Type I by IUPAC classification. The average pore sizes were about 19-21${\AA}$. The specific surface areas ($S_{BET}$) of pellet typed ACs increased with increasing the activation temperature and time. Specific surface area of AC treated for 90 min at temperature $900^{\circ}C$ was 1082 $m^2/g$. The methylene blue numbers continuously increased with increasing the activation temperature and time. On the other hand, iodine numbers highly increased till activation time of 60 min, but the rate of increase of iodine numbers decreased after that time. This indicates that new micropores were created and the existing micropores turned into mesopores and macropores because of increased reactivity of carbon surface and $H_2O$.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.57-61
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• 2014

In this study, carbon aerogel (CA) was synthesized using a soft-template method, and the optimum conditions for the adsorption of carbon dioxide ($CO_2$) by the carbon aerogel were evaluated by controlling the activation temperature. KOH was used as the activation agent at a KOH/CA activation ratio of 4:1. Three types of activated CAs were synthesized at activation temperatures of $800^{\circ}C$(CA-K-800), $900^{\circ}C$(CA-K-900), and $1000^{\circ}C$(CA-K-1000), and their surface and pore characteristics along with the $CO_2$ adsorption characteristics were examined. The results showed that with the increase in activation temperature from 800 to $900^{\circ}C$, the total pore volume and specific surface area sharply increased from 1.2165 to $1.2500cm^3/g$ and 1281 to $1526m^2/g$, respectively. However, the values for both these parameters decreased at temperatures above $1000^{\circ}C$. The best $CO_2$ adsorption capacity of 10.9 wt % was obtained for the CA-K-900 sample at 298 K and 1 bar. This result highlights the importance of the structural and textural characteristics of the carbon aerogel, prepared at different activation temperatures on $CO_2$ adsorption behaviors.

• 한국환경과학회지
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• 제24권12호
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• pp.1601-1608
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• 2015

This study evaluates heavy metal(Cu and Cr) adsorption characteristics produced from food waste charcoal extracted in an optimal operation condition after analyzing activated charcoal of iodine adsorption and heavy metals that derived from an activation process of carbide by the developed by-products of food waste treatment facility using the methods from previous studies. As experiment apparatus, this study used a tube-shaped high temp furnace. The mixing ratio of by-products of food waste treatment facility, carbide, and activation component($ZnCl_2$) was 1:1. The experiment was proceeded as adjusting the activation temperature from 400 to $800^{\circ}C$ and activation time from 30 to 120 minutes. The optimal activation condition for iodine absorption was 90 minutes at $700^{\circ}C$ and by using the produced food waste charcoal, this study conducted an experiment on absorption of heavy metals (Cu and Cr) as changing pH of artificial wastewater and stirring time. As a result, pH 7 showed the highest heavy metal decontamination ratio and in terms of stirring time, it revealed balance adsorption after 10 minutes. This result can be particularly applied as basic data for recyclability of high concentration organic waste, by-products of food waste treatment facility, as an food waste charcoal.

• PNF and Movement
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• 제14권2호
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• pp.113-120
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• 2016

Purpose: The purpose of this study was to compare the intramuscular activation of the scapular stabilizing muscles and the upper trapezius/middle serratus anterior (UT/MSA) ratios during shrug exercise and proprioceptive neuromuscular facilitation (PNF) scapular pattern exercise. Methods: The participants of this study were 13 young adult men who voluntarily consented to participate in this experiment after listening to its purpose and methods. All participants were instructed on maximal voluntary isometric contraction and scapular exercises. The intramuscular activation of the upper trapezius (UT), lower trapezius (LT), middle serratus anterior (MSA), and lower serratus anterior (LSA) muscles while performing scapular exercises in a side-lying position were measured using surface electromyography. To analyze the muscle activation and UT/MSA ratio between the two exercises, a one-way repeated ANOVA was performed. Post-hoc analyses were conducted using Tukey's multiple comparison and analysis. Hamstring flexibility for each group was measured by a passive straight leg raising test. Results: The shrug exercise showed significantly higher UT activation compared to PNF anterior elevation and posterior elevation scapular patterns. The PNF scapular anterior elevation pattern showed significantly higher serratus anterior activation than the shrug exercise. Additionally, the UT/MSA ratios were significantly lower in the PNF scapular anterior elevation pattern than in the two exercises. Conclusion: Although shrug exercise was effective for strengthening UT, the PNF scapular anterior elevation pattern may be effective for strengthening MSA and improving the UT/MSA ratio.

• PNF and Movement
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• 제17권3호
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• pp.441-450
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• 2019

Purpose: This study identified the co-activation of quadriceps and hamstring muscles during hamstring strengthening exercises in healthy adults. Methods: Twenty-one participants were required for the present study design to achieve 80% power, 0.8 effect size (η2), and an alpha level of 0.05. Thus, this study recruited 21 healthy adults. All participants performed Nordic exercises, bridge exercises, and one-leg deadlifts randomly. The activity of the rectus femoris, vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), and semitendinosus (SM) were measured. In addition, the ratios of VM/VL and hamstring/quadriceps (HQ) were measured during the three hamstring strengthening exercises using electromyography. One-way ANOVA was used to compare the co-activation of quadriceps and hamstring muscles in the three exercises. Results: The activity of VM and VL during the performance of one-leg deadlifts was significantly higher than the other two exercises. The BF had significantly higher activity during the Nordic exercises compared to the other two exercises. In addition, the SM activation was significantly greater during Nordic exercises than one-leg deadlifts. Additionally, there was significant difference in HQ ratio among hamstring strengthening exercises. In specific, the one-leg deadlifts yielded a significantly lower HQ ratio. Conclusion: This study revealed that one-leg deadlifts are effective in rehabilitation for anterior cruciate ligament injury. In addition, Nordic exercises can be recommended to facilitate hamstring muscle activation.

• 대한치과교정학회지
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• 제31권2호통권85호
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• pp.199-207
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• 2001

본 연구는 교정치료를 시행함에 있어 전치부 crowding을 해결하기 위한 견치의 단독견인 방법중 새로운 segmented TMA T-loop spring으로 견치 후방견인시 치근단과 그 주위 치조골에서의 응력상태를 알아보기 위해 시행되었다. PL-3 epoxy resin으로 광탄성 모형을 제작하여 B/L ratio가 0.25, 0.5, 0.75인 위치로 T-loop을 위치시키고 각 위치에서 5mm, 3mm, 1mm activation하였다. 이후 광탄성 응력 해석장치를 이용하여 견치견인시 치근단과 그 주위 치조골에서의 초기 응력 상태를 광탄성법으로 분석한 바, 다음과 같은 결론을 얻었다. 1. T-looP 위치에 상관없이 activation량이 감소할수록 상악 1소구치 발치부위에 응력이 감소하였고 상악 1대구치의 함입응력은 증가하였다. 2. 5mm activation시 T-loop위치가 구치부쪽으로 이동할수록 상악 1소구치 발치부위에 응력이 증가하였다. 3. 3mm activation시 T-loop위치가 구치부쪽으로 이동할수록 상악 1소구치 발치부위와 상악 1대구치 협측 근심치근 근심면하방 1/2부위에 응력이 증가하였다. 4. 1mm activation시 T-loop위치가 견치쪽으로 이동할수록 상악 견치의 근심치근면 상방과 치근첨 하방의 응력이 증가하였다. 5. B/L ratio가 0.25이고 3mm activation시 상악견치의 치체이동이 나타났다. 이상의 결과를 종합해볼 때 segmented T-loop spring의 근, 원심 위치 와 activation량을 조절하여 원하는 치아이동과 고정원 조절이 가능하다고 사료된다.

• 한국환경과학회지
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• 제25권2호
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• pp.281-288
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• 2016

After analyzing of heating value of four kinds of RDF, the RDF-D has the highest heating value, was chosen to be mixed with carbonized sludge by different ratio. The 85%:15% ratio, which has the highest efficiency, was analyzed with thermogravimetric and pyrolysis kinetics. Applying of Kissinger method, activation energy was obtained from slope which is calculated from relation of ln(${\beta}/T^2{_m}$) and $1/T_m$. The kinetic parameters obtained from Kissinger method were 46.06 kJ/mol of RDF, 55.99 kJ/mol of carbonized sludge and 40.68 kJ/mol of mixture of RDF and carbonized sludge. The mixture of RDF and carbonized sludge has the lowest activation energy and frequency factor, during thermal decomposition reaction it has the slowest reaction rate and needs the lowest energy. Although activation energy with pyrolysis of RDF was irregularly scattered, it showed that activation energy was stabilized by co-pyrolysis of RDF and additives(Carbonized Sludge).

• 한국전문물리치료학회지
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• 제19권3호
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• pp.11-19
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• 2012

This study aimed to investigate whether isometric lower limb exercise can activate contralateral trunk muscles and whether the magnitude of muscle activation is related to lower limb movement in sitting. This study included 25 healthy young subjects (20 males and 5 females). The magnitude of trunk muscle activation was measured using surface electromyography (EMG) during hip flexion, extension, adduction, and abduction, and a significant difference was observed in the activation levels of trunk muscles among the tests (p<.01). The EMG activity of the multifidus (MF) and erector spinae (ES) muscles on the contralateral side were significantly greater during hip extension. However, the activation levels of the contralateral internal oblique (IO) and rectus abdominis (RA) muscles were greatest during hip flexion. The MF : ES EMG ratio was significantly greater during hip isometric during hip isometric flexion and abduction compared to hip extension and adduction. There was no significantly difference in the IO : RA ratio during the isometric contractions toward different directions. These findings indicate that isometric lower limb exercise can elicit trunk muscle contraction on the contralateral side and may therefore be helped for developing contralateral trunk muscle strength in individuals undergoing rehabilitation.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.11-19
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• 2017

Background: Methods for exercising serratus anterior (SA) and upper trapezius (UT) muscles are important for the recovery of patients with various shoulder disorders, yet the efficacy of closed or open kinetic chain exercises have not yet been evaluated. Objects: The purpose of this study was to compare the activation of the SA and UT muscles during scapular protraction considering both closed and open kinetic chain exercises. Methods: Thirty subjects were randomly divided into experimental groups (closed kinetic chain exercise) and control groups (open kinetic chain exercise) in which scapular protraction was performed at $90^{\circ}$ or $125^{\circ}$ shoulder flexion. Electromyographic activity data were collected from the SA and UT muscles per position and exercise method. Results: Separate mixed 2-way analysis of variance showed significant differences in the activation of the SA (F1,28=6.447, p=.017) and the UT (F1,28=35.450, p=.001) muscles between the groups at $90^{\circ}$ and $125^{\circ}$ shoulder flexion. Also, the SA/UT ratio measures at $90^{\circ}$ and $125^{\circ}$ shoulder flexion significantly differed between the groups (F1,28=15.457, p=.001). That is, the closed chain exercise was more effective than open chain exercise for strengthening the SA muscle and controlling the UT muscle, $125^{\circ}$ of shoulder joint was more effective than $90^{\circ}$. Conclusion: The findings suggest that scapular protraction with shoulder $125^{\circ}$ flexion at the closed kinetic chain exercise may be more effective in increasing SA muscle activation and decreasing UT muscle activation as well as increasing the SA/UT ratio than open kinetic chain exercise.