• Korean Journal of Applied Biomechanics
• /
• v.31 no.1
• /
• pp.1-15
• /
• 2021

Objective: The aim of this study was to investigate 1) the difference in static lower extremity alignment (SLEA) according to a history of lateral ankle sprain (LAS), 2) to identify SLEA factors affecting LAS, and 3) to present the cut-off value and 4) the usefulness and limitations of the SLEA measurement. Method: This case-control study recruited 88 men (age: 27.78±4.69 yrs) and 39 women (age: 24.62±4.20 yrs) subjects with and without LAS. SLEA measurement protocol included Q angle, tibiofemoral angle, genu recurvatum, rear foot (RF) angle, tibal varum and torsion, navicular drop, ankle dorsiflexion range of motion (DF ROM). Independent t-test, logistic regression and receiver operating characteristic (ROC) curve were used for statistical analysis. Results: Men with a history of LAS had significantly smaller Q angles both in standing and in supine position, while women with a history of LAS had significantly greater DF ROM in non-weight bearing (NWB; p < 0.05). Logistic regression model suggests tibial varum (OR = 0.779, p = 0.021) and WB DF ROM (OR = 1.067, p = 0.045) were associated with LAS in men. In case of women, there were no significant SLEA factors for LAS, however, ROC curve analysis revealed standing RF angle (AUC = 0.647, p = 0.028) and NWB DF ROM (AUC = 0.648, p = 0.026) could be affecting factors for LAS. Conclusion: There are differences in SLEA according to the history of LAS, furthermore, the identified items were different by sex. In case of men, tibial varum and WB DF ROM affect LAS occurrence. Standing RF angle and NWB DF ROM of women could be a predictor for LAS. However, since the sensitivity and specificity in most of the SLEA measurements are low, kinematic in dynamic tasks should be considered together for a more accurate evaluation of LAS risk.

• Korean Journal of Applied Biomechanics
• /
• v.12 no.1
• /
• pp.47-61
• /
• 2002

The purpose of this study was to determined the force and moment of the ankle and the knee joint at different step length relative to the length of the lower extremity during a steady running. Six digital cameras(Qualisis) and a forceplatform(A.M.T.I) were used to obtain the kinematic data of the segments and kinetic data on the running at speed of 5.18m/s. The force and moment measured from six subjects participated in this study were limited to the support phase and their values were averaged at the moment of heel strike, mid stance, and toe off of a running for making a comparison between the condition 1(relative step length 1.1) and the condition 2(relative step length 1.4). It was concluded that internal forces except mediolateral force of the condition 2 were greater in the ankle and the knee joint than those of the condition 1, but all moments of condition 2 were greater from the descriptive statistic point of view. For the future study, it was needed to consider a number of subjects, a various running speed, and a individual step preference for applying generally results to the running strategy.

• Journal of radiological science and technology
• /
• v.21 no.2
• /
• pp.53-56
• /
• 1998

Highly sensitive $CaSO_4:Tm$ TLD is fabricated and their trap parameters are determined. The glow curve of $CaSO_4:Tm$ consists of three glow peaks and these peaks are isolated by the thermal bleaching method. The isolated glow peaks are fitted by a least squares method. The activation energies are 0.68, 0.82 and 1.03 eV. The frequency factors are $8.09{\times}10^8,\;9.14{\times}10^8$ and $1.03{\times}10^9/s$, and the kinetic orders are 1.37, 1.54 and 1.68, respectively. The optimum temperature range of the main peak for radiation dosimetry is between 220 and $290^{\circ}C$.

• Korean Journal of Applied Biomechanics
• /
• v.20 no.2
• /
• pp.167-174
• /
• 2010

This study aims to quantitatively compare and analyze kinetic variables in the motion of male and female professional golfers to suggest basic scientific materials for golf iron swing. Five male and five female professional golfers participated in this experiment. Ground reaction force and foot pressure were measured during performing 10 swings for each participants using an iron club. The result of the ground reaction force indicates that the force occurs at the left foot toward right(-) direction in the mid-downswing(E3) and impact(E4) events in X-axis, while it occurs at the right foot toward anterior(-) direction in Y-axis for both male and female, showing a big difference between them. Also, in Z-axis, large force occurs at the left foot in most events. The analyzed result on foot pressure indicates that men have the highest pressure and area at the left foot, and women have the highest ones at the right foot in the mid-downswing(E3) and impact(E4) events in the max foot pressure, ground contact area and average pressure. It is considered that there is difference of central movement methods between men and women. Thus, different education and training on golf swing should be necessary by gender due to their different patterns of golf iron swing.

• Korean Journal of Applied Biomechanics
• /
• v.20 no.2
• /
• pp.129-137
• /
• 2010

The purpose of this study is to investigate the effect of a 12-week aquatic exercise on obstacle gait in older women. Originally, 20 healthy female elderly participated this study but 12 of them completed the program. All participants were trained in the aquatic exercise program by an authorized trainer. They had come to the authors' lab three times during training period(0, 6, 12 weeks) and performed obstacle gait with three different height(0, 30, and 50% of leg length). After performed 3-Dimensional motion analysis following results were found. (1) For the CV, MVHC, TC, HC, statistically significances were shown in obstacle height. Although significant training effects were not shown, all variables showed typical patterns and it was considered as efficient motion to overcome the height obstacles. (2) The anterior-posterior and vertical GRF of support leg during support phase were revealed in height effect but in training one. However, differences between Peak 1 and Peak 2 in vertical GRF increased as training period increased. (3) Knee and hip resultant joint moments were affected by training but ankle resultant moments remained unchanged.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.1
• /
• pp.19-24
• /
• 2013

The aim of the study was a quantitative analysis of elite athlete's $540^{\circ}$ Dwihuryeochagi and effects of ground movements to the jumping height and kicking velocity. Eleven elite players(Taekwondo demonstration team) participated in this study. In order to get the kinetic and kinematic variables, ten Vicon cameras and a force plate were used. Foot segment velocity(FSV), vertical ground reaction force(GRF), impulse, ground time(GT) in phase 1, trunk angular velocity(TAV), vertical center of gravity(COG), flight time(FT) in phase 2 and kicking leg segment velocity(KSV) in phase 3 were measured and analyzed. Results indicated that there were similar patterns of variables among phases between subjects. Non-significant correlation(r=.145) between flight time(FT) and impulse was found. Also non-significant correlation(r=.119) between center of gravity(COG) and impulse was found. In conclusions, there were similar strategies in phase 1, phase 2, and phase 3 between subjects.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.1
• /
• pp.11-17
• /
• 2013

The purpose of this study was to provide a fundamental information for enhancing 110m hurdlers' performance through conducting comparative biomechanical analysis between Skilled Group(SG) and Less-Skilled Group(LSG) those who are not in the first section of 110m hurdles. To persue the purpose of this study, total of 10 hurdlers participated. Then they were divided into two groups; SG: five hurdlers who have won awards with 14-second range at 2010 national track and field event, and LSG: five hudlers who did not win any awards with 15-second range. Three-dimensional motion analysis with 12 infrared cameras(Oqus 300, Qualisys) and 1 force plate(Type 9286AA, Kistler) was performed. From this study following conclusions were obtained. 1) For the overall runtime, SG revealed faster elapsed time than that of LSG. 2) At E4, LSG showed greater trunk angle than that of SG. 3) At E3 LSG revealed higher angular velocities than that of SG. 4) No significant differences was found for AP GRF between groups but LSG showed greater VGRF than that of SG.

• Journal of Surface Science and Engineering
• /
• v.49 no.6
• /
• pp.498-506
• /
• 2016

Electrochemical measurement using a LSCF6428 electrode was performed to estimate the oxygen potential gradient in the electrode layer and a long time stability test was performed by applied potential to learn the overpotential effect on the LSCF6428 electrode. By fitting the observed impedance spectra, it was obtained that the amount of faradic current decreased with distance from cathode/electrolyte interface. Oxygen potential gradient was estimated to occur within 1 um region from the cathode/electrolyte interface at an oxygen partial pressure of 10-1 bar. The segregation of cation rich phases in the LSCF6428 electrode suggests that kinetic decomposition took place. However, impedance response after applying the potential showed no changes in the electrode compared with before applying potential. The obtained results suggest that segregation of a secondary phase in a LSCF6428 cathode is not related to performance degradation for solid oxide fuel cells (SOFCs).

• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.863-866
• /
• 2011

The electrode reaction of $Eu^{3+}$ in a LiCl-KCl eutectic melt has been re-examined using cyclic voltammetry (CV). In this work, for the first time, the kinetic details of a $Eu^{3+}/Eu^{2+}$ redox system have been completely elucidated, along with the thermodynamic property, through a curve fitting applied to experimental CV data, which were obtained in a wide scan rate range of 0.5 to 10 V/s. The simulated results showed an excellent fit to all experimental CV data simultaneously, even though the curve fittings were performed within a large dynamic range of initial transfer coefficient values, formal potentials, and standard rate constants. As a result, a proper formal potential, transfer coefficient, and standard rate constant for the $Eu^{3+}/Eu^{2+}$ redox system were successfully extracted using the CV curve fitting.

• Advances in environmental research
• /
• v.3 no.4
• /
• pp.293-306
• /
• 2014

The present study primarily focuses on the evaluation of the comparative effect of chemical coagulation and ultrasonication for elimination of aromatic amines (AAs) present in anaerobically pretreated textile wastewater containing different types of dyes including azo dyes. Color and COD reduction was also monitored at the optimized conditions. The production of AAs was measured spectrophotometrically in the form of total aromatic amines (TAAs) and also verified with high performance liquid chromatography (HPLC) selectively. A composite coagulant, magnesium chloride (MC) aided with aluminium chlorohydrate (ACH) in an equal ratio (MC + ACH) was utilized during the coagulation process, which yielded 31% of TAAs removal along with 85% of color and 52% of COD reduction. At optimized power (200 W) and sonication time (5 h), an appreciable TAAs degradation efficiency (85%) was observed along with 51% color reduction and 62% COD removal using ultrasonication. The chromatographic data indicate that sulphanilic acid and benzidine types of aromatic amines were produced after the reductive cleavage of utilized textile dyes, which were effectively mineralized after ultrasonication. The degradation followed the first order kinetics with a correlation coefficient ($R^2$) of 0.89 and a first-order kinetic constant (k) of $0.0073min^{-1}$.