• Physical Therapy Korea
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• v.23 no.1
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• pp.11-19
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• 2016

Background: Investigation in gender differences of kinetics and kinematics for individuals with patellar femoral pain syndrome (PFPS) was not sufficiently performed. Objects: The purpose of this study is that whether there is a difference depending on gender from muscle activity and strength and knee valgus angle during controlled single-leg squat which is widely used as clinical movement test for the patient with PFPS. Methods: 20 young adults (10 men, $20.0\pm}2.1$years; 10 women, $20.4{\pm}2.1$years) with PFPS were voluntarily recruited in this study. Muscle activity and strength and knee valgus angle were collected during single-leg squat. Independent t-test and Mann-Whitney test were used to compare the differences between groups of male and female. Results: Rectus femoris (t=-2.204, p=.041) and vastus medialis oblique (t=-2.151, p=.045) muscle activity of women were significantly higher than male group. Normalized muscle strength of hip and knee muscles showed a significant difference between men and women (p<.05). Valgus angle of the knee in women (t=-2.450, p=.025) were increased significantly than men. Conclusion: The therapist would consider the characteristics of these gender differences during performing movement test, exercise, and education for the individuals with PFPS.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.33-39
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• 2010

The purpose of this study was to investigate the changes in walking pattern of the elderly during inclined walkway with uneven surfaces and level walking. 10 young($26.3{\pm}1.3$ years, $174.3{\pm}5.3\;cm$, $69.5{\pm}9.5\;kg$) and 13 elderly($72.4{\pm}5.2$ years, $164.5{\pm}5.4\;cm$, $66.1{\pm}9.6\;kg$) male subjects were participated in the experiment. Experiment consisted of 2 walking conditions: horizontal and inclined walkway with uneven surfaces. 3D motion capturing system were used to acquire and analyze walking motion data with sampling frequency of 120 Hz. To compare differences between conditions, kinematic variables(walking speed, stance-swing ratio, hip joint angle, knee joint angle, ankle joint angle, pelvic rotation angle) were used. Results showed that there were some changes of elderly walking pattern in inclined walkway with uneven surfaces: hip joint(adduction and rotation) and pelvic movement pattern. These changes by inclination and surface may affect gait pattern of young subjects as well as elderly subjects. However, in case of elderly it revealed more unstable gait than the young. Further study is necessary to clarify changes in walking pattern for elderly by considering various gait variables including head movement and various walkway conditions.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.369-376
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• 2013

The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.532-536
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• 2008

In this paper, we propose the method to measure tensions of character motions, using LMA (Laban Movement Analysis). Using tension values, we tan take advantage of them as a standard for synchronization of motion and BGM(Back Ground Music). In LMA, a motion is divided into 4 space-time factors which are called Efforts, and each Effort has two bases opposed to each other. We can analyze the motion by justifying which basis is stronger than the other in each Effort of motion. To measure quantitatively tension values, we propose some equations based on kinematics and dynamics. Then we can measure the tension value by the weighted sum of values calculated from those equations. Each weight can be determined by the optimization process which tries to minimize the difference between the calculated tension value and human's decision. The experimental result shows that the in creasing order of the motion tension value is similar to that of the tension score given by human.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.169-170
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• 2006

The purpose of this study was to evaluate the smoothness of the gait pattern according to shoe, walking speed, and slope. Eleven male university students used three types(running shoes, mounting climbing boots, elevated forefoot walking shoes) of shoes at various walking speeds(1.19, 1.25, 1.33, 1.56, 1.78, 1.9, 2.0, 2.11, 2.33m/s) and gradients (0, 3, 6, 10%) on a treadmill. Three-dimensional motion analysis (Motion Analysis Corp, Santa Rosa, CA, USA) was conducted with 4 Falcon high speed cameras. The results showed that elevated forefoot walking shoes had the lowest value of normalized jerk at the heel, which means that elevated forefoot walking shoes had the smoothest walking pattern at the heel. In contrast, elevated forefoot walking shoes had greater normalized jerk at the center of mass (COM) at most walking speeds, which means that the smoothness of gait pattern at the center of mass is the lowest for the elevated forefoot walking shoes. This movement at the COM might even have a beneficial effect of activating muscles in the back and abdomen more than other shoes.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.119-127
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• 2010

Recently, we have launched a large-scale articulatory study to investigate how the three-way contrastive stops (i.e., lenis, fortis, and aspirated) in Korean are kinematically expressed (i.e., in terms of articulatory movement characteristics) in various contexts, using a magnetometer (Electromagnetic Articulography). In this paper, we report some preliminary results about how the three-way bilabial series /p,$p^h,p^*$/ produced in /Ca/ context in isolation are kinematically characterized not only during the lip closure but also during the following vocalic articulation. Some important notes could be made from the results. First, the degree of lip constriction (as measured by the lip aperture between the upper and lower lips) was smaller for the lenis /p/ and larger for the fortis/aspirated /$p^*,p^h$/, showing a two-way distinction during the closure. Second, the tongue lowering for the following vowel was more extreme after the lenis /p/ than after the fortis/aspirated /$p^*,p^h$/. Regarding this vocalic articulatory difference in the tongue height, we discussed the possibility that the articulatory tension associated with the fortis/aspirated stops is further reflected in the lingual vocalic movement maintaining the tongue position to a certain level for the following vowel /a/, while the lenis consonant does not impose such articulatory constraints, resulting in more tongue lowering. Finally, the temporal relationship between the release of the stop closure and the lowest tongue position of the following vowel remained constant, suggesting that CV coordination is invariantly maintained across the consonant type. This pattern was interpreted as supporting the view that the consonant and vowel gestures are coordinated in much the same way across languages.

• PNF and Movement
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• v.21 no.1
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• pp.19-25
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• 2023

Purpose: The aim of this study is to determine the effects of gastrocnemius stretching with talus-stabilizing taping on ankle dorsiflexion and subtalar joint pronation during walking. Methods: In total, 26 subjects with limited ankle dorsiflexion were equally divided into two groups: a gastrocnemius stretching with talus-stabilizing taping group (13 subjects) and a gastrocnemius stretching group (13 subjects). They were assessed according to ankle dorsiflexion and subtalar joint pronation during walking before and after an intervention, which involved two types of gastrocnemius stretches performed three times a week for six weeks. Results: Ankle dorsiflexion was significantly increased in both groups (p<0.05), though the gastrocnemius stretching with talus-stabilizing taping group showed a significantly greater improvement in ankle dorsiflexion than the gastrocnemius stretching group (p<0.05). However, subtalar joint pronation showed no difference between the two groups before and after (p>0.05), also between groups (p>0.05). Conclusion: Gastrocnemius stretching with talus-stabilizing taping is a useful stretching exercise that improves ankle dorsiflexion during walking in subjects with limited ankle dorsiflexion movement.

• Korean Journal of Applied Biomechanics
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• v.34 no.2
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• pp.81-92
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• 2024

Objective: The purpose of this study was to analyze the impact acceleration, shock attenuation and biomechanical variables at various running speed. Method: 20 subjects (height: 176.15 ± 0.63 cm, weight: 70.95 ± 9.77 kg, age: 27.00 ± 4.65 yrs.) participated in this study. The subjects ran at four different speeds (2.5 m/s, 3.0 m/s, 3.5 m/s, 4.0 m/s). Three-dimensional accelerometers were attached to the distal tibia, sternum and head. Gait parameters, biomechanical variables (lower extremity joint angle, moment, power and ground reaction force) and acceleration variables (impact acceleration, shock attenuation) were calculated during the stance phase of the running. Repeated measures ANOVA was used with an alpha level of .05. Results: In gait parameters, decreased stance time, increasing stride length and stride frequency with increasing running speed. And at swing time 2.5 m/s and 4.0 m/s was decreased compared to 3.0 m/s and 3.5 m/s. Biomechanical variables statistically increased with increasing running speed except knee joint ROM, maximum ankle dorsiflexion moment, and maximum hip flexion moment. In acceleration variables as the running speed increased (2.5 m/s to 4.0 m/s), the impact acceleration on the distal tibia increased by more than twice, while the sternum and head increased by approximately 1.1 and 1.2 times, respectively. And shock attenuation (tibia to head) increased as the running speed increased. Conclusion: When running speed increases, the magnitude and increasing rate of sternum and head acceleration are lower compared to the proximal tibia, while shock attenuation increases. This suggests that limiting trunk movement and increasing lower limb movement effectively reduce impact from increased shock. However, to fully understand the body's mechanism for reducing shock, further studies are needed with accelerometers attached to more segments to examine their relationship with kinematic variables.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.61-73
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• 2007

The purpose of this study was to investigate the influence of the muscular endurance on the kinematic factors during a prolonged run. Subjects, 12 males, who were divided into three groups(lower group, general group, and in higher group) after measuring the lower limb's muscular endurance previously. They were asked toe run on the treadmill at 7.4km/h of speed. To analyze the kinematics parameters of the trunk during running, the ProReflex MCU Camera(Qualisys, Sweden) were used. All parameters were sampled from 5 minute, 40 minute, and 60 minute moments during running. An ANOVA with Repeated Measure was used to test the statistic significance between and within groups for all parameters determined with SPSS 11.0. Significance was defined as p<.05. The conclusions were as follows; There was significantly difference within(lapse of running time) groups in the take-off and minimum knee angle event of swing phase of the trunk flexion and extension. In conclusion, the muscular endurance affected on movement of the trunk during a prolonged run. In addition, it showed that there was significant difference in the energy consumption by lapse of running time. Therefore, it seems to be relationships between the muscular endurance and running efficiency.

• The Journal of Korea Robotics Society
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• v.7 no.4
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• pp.284-291
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• 2012

Recently, development of underwater robot has actively been in progress in the world as ROV(Remotely Operator Vehicle) and AUV(Autonomous Unmmanded Vehicle) style. But KIOST(Korea Institute of Ocean Science and Technology), beginning in 2010, launched the R&D project to develop the robot, dubbed CRABSTER(Crab + (Lob)ster) in a bid to enhance the safety and efficiency of resource exploration. CRABSTER has been designed to be able to walk and swim with its own legs without screws. Among many research subjects regarding CRABSTER, optimal swimming patterns are handled in this paper. In previous studies, drag forces during one period with different values for angle of each joint were derived. However kinematics of real-robot and fluid-dynamics are not considered. We conducted simulations with an optimization algorithm for swimming by considering simplified fluid dynamics in this paper. Drag-coefficients applied to the simulation were approximated values calculated by CFD(Computational Fluid Dynamics : Tecplot 360, ANSYS). In addition, optimized swimming patterns were applied to a real robot. The experiments with the real robot were conducted in circumstances in the water. As a result, when the experiments were carried out in the water, a regular pattern of drag force output came out depending on the movement of the robot. We confirmed the fact that the drag forces from the simulation and the experiment has a high similarity.