• 한국운동역학회지
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• 제20권3호
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• pp.261-266
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• 2010

Human body is hard to be in perfect balance during walking. Most of time the trunk is supported by one leg and the center of mass(COM) falls to the contralateral side. Thus, dynamic variables such as the velocity of the COM should be considered when gait stability is evaluated. The purpose of this study was to investigate whether the extrapolated center of mass(XCom) which utilized the COM position and its velocity, is appropriate to evaluate gait stability. Ten healthy adults participated in this study and performed 3 different types of gaits(normal(NG), hands on waists(HWG), and hands on shoulders(HSG)) onto 4 different types of obstacle(obstacle height: 0%, 30%, 40% and 50% of leg length). Medio-lateral Com-CoP and XCom-CoP inclination angle were calculated during support phase. For all condition, greater M-L XCoM-CoP inclination angles were found(p<.05) compared with those of matched obstacle height CoM-CoP. Especially, M-L XCoM-CoP inclination angle at 50% height revealed the best condition for monitoring dynamic stability. Significantly increased in M-L XCoM-CoP inclination angle was found(p<.05) as obstacle height increased on NG and HWG.

• 한국운동역학회지
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• 제30권3호
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• pp.265-273
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• 2020

Objective: The aim of this study was to investigate the effect of participation in contact sports on neurocognitive scores, dual-task walking velocity, and cognitive costs in retired athletes. Method: Forty-four retired athletes (mean age = 26.4±5.5 yrs) and thirty-eight controls (mean age = 26.1±4.9 yrs) participated in this study. Neurocognitive score was collected using computerized neurocognitive testing using RehaCom. Gait velocity was collected one single task, four dual-tasks, and two multi-tasks using Optogait. Mann-Whitney U test was performed to compared differences in cognitive scores among groups. A mixed-design two-way ANOVA and Bonferroni posthoc test were used to assess the effect of group and walking tasks for each condition. Results: The auditory divided attention of neurocognitive score of retired athletes was higher than the control group (p < 0.05). No statistical differences were observed in the other neurocognitive scores between groups. The changes in walking velocity and cognitive costs according to the dual-task walking tests differed between the two groups (p < 0.05). Conclusion: Although participation in contact sports did not affect the neurocognitive results of retired athletes, it could be confirmed that the reduction in walking velocity and an increase in cognitive costs during dual-task walking. Rather than observing only neurocognitive scores as a single evaluation item for cognitive evaluation of retired athletes in relation to daily life, the application of the dual-task gait test may provide useful information.

• 한국운동역학회지
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• 제24권3호
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• pp.249-258
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• 2014

The purpose of this study was to investigate the different patterns of the lower limb between elderly and adult females to reduce the rate of falls. Ten old females(age: $73.1{\pm}2.69yrs$, height: $151.9{\pm}4.82cm$, mass: $57.36{\pm}5.36$) and ten adult females(age: $28\pm}4.76$ yrs, height: $160.6{\pm}6.83cm$, mass: $53.9{\pm}8.44$) were participated in this experiment. The gait motions were captured with Qualisys system and variables were calculated with Visual-3D. The following results were found. The elderly female group showed bigger inclination angle between COM and COP than the adult female group so that the dynamic stability was reduced in walking for the compensation with a bigger stride width. The elderly female group ensure for the necessary forward movement of COM in order to replace the decreased function of ankle and knee joint. If the distance between COM and COP is closer and the energy reduction of a specific joint is reduced, they could prevent the elderly female's falling rate by strengthening of muscles which were related the extension of ankle joint.

• The Journal of Korean Physical Therapy
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• 제21권2호
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• pp.87-95
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• 2009

Purpose: This study reports the basic reference data of the specific gait parameters for Korean normal adults. Methods: The basic gait parameters were extracted from 73 Adults (35 men and 38 women), 18 to 33 years of age, using a Vicon MX motion analysis system. The segment kinetics, such as joint moment and power, was analyzed at the hip, knee and ankle. Results: The motion patterns are typically associated with a specific phase of the gait cycle. The temporal-spatial gait parameters of Korean normal adults, such as cadence, walking speed, stride length, single support and double support, were similar to the other western reference data. The kinetic parameters of Korean normal adults, such as joint moments of force, joint mechanical power generation or absorption and ground reaction forces, were also similar to other western reference datasets. Conclusion: This study demonstrates that objective gait analysis can be used to document the gait patterns of normal healthy adults. The techniques of 3-dimensional temporal-spatial gait parameters and kinematic parameters analysis can provide a detailed biomechanical description of a normal and pathological gait.

• 한국운동역학회지
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• 제16권2호
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• pp.85-95
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• 2006

The purpose of this study of which 10 University students in their twenties are the objects was to examine the causal differences of kinematic and electromyography during power walking and normal gait. We came to the following conclusions. 1) It took less time to stance phase, swing phase and whole gait time during power walking compared with normal gait. 2) During power walking, the step length and step length and lower limb length are longer than that of normal gait. 3) During power walking, ankle joint angle became more plantar flexed at LIC and RTO, knee joint angle become more flexed, so did hip joint angle at LIC and RTO. Besides during power walking the shoulder joint angle movement was bigger and elbow joint angle was more flexed as the trait of power walking. 4) During power walking, through out the phase the muscle activity of all muscle was higher expecially the muscle activity of Biceps brachii, gastrocnemius medialis, gastrocnemius lateralis, Soleus was higher. Therefore during power walking, one's scope of activity and muscle activity is relatively higher than those of normal gait, so power walking helps one strengthen muscular power and energy metabolism. This will be useful information for those who are interested in diet and well-being.

• 한국운동역학회지
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• 제15권4호
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• pp.131-142
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• 2005

This study was investigated the stability of the AK amputee gait through analysing the variability on kinematic variables between the sound leg and the prosthetic limb. The one male, AK amputee who could walk for himself with his prosthetic limb was participated in this study. Six cameras of the MCU 240 and the QTM(Qualisys Track Manager) software were used for data collecting in this study. The relative angle of both segments was the difference between the absolute angle of the distal segment and the absolute angle of the proximal segment. The coupling angles between the prosthetic limb and the sound leg were caculated on the thigh Flexion/Extension in relative to the shank Flexion/Extension and the shank Flexion/Extension n relative to the foot Flexion/Extension. In order to evaluate the variability of segment and joint angle, C.V. was used, and to evaluate the variability for coupling angles, the Relative motion calculated by vector coding method of the continuous methods was used. As stated, the gait pattern of the prosthetic limb was almost similar gait pattern of the sound leg, but the prosthetic limb showed that the gait pattern of the sound leg and the prosthetic limb were not stable against the sound leg.

• 대한의용생체공학회:의공학회지
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• 제32권2호
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• pp.93-104
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• 2011

The purpose of this study was to investigate lower-limb joint torque of the two groups as it changed by somatosensory stimulation during the descent down three stairs of different heights and to describe the difference between the two groups, which are young people group and elderly people group. Subjects of each groups climbed down a stair at four stimulation conditions, which are non-stimulation, tibialis anterior tendon stimulation, achilles tendon stimulation, tibialis anterior - achilles tendon stimulation. Motion capture data were collected using 3D optoelectric motion tracking system that utilizes active infrared LEDs, near infrared sensor and force plate. The obtained motion capture data was used to build 3D computer simulation model. The results show that lower-limb joint torque of the two groups changed with somatosensory stimulation as they descended the stairs and the joint torque of the two groups differed from each other.

• 한국운동역학회지
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• 제20권4호
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• pp.365-372
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• 2010

The purpose of this study were to analyze the changes in kinematic and kinetic parameters and to find biomechanical benefits of Nordic Walking and normal gait performed under the same velocity. Nine participants(age: $26.73{\pm}3.28$ year, height: $182.45{\pm}4.62\;cm$, weight: $76.59{\pm}6.84\;kg$) was chosen. The velocity of gait was set by 5.75 km/h which was made by a Nordic Walking professional. The data were collected by using VICON with 8 cameras to analyze kinematic variables with 200 Hz and force platform to analyze kinetic variables with 2000 Hz. The results of this study were as follows. First, when compared with Normal gait, Nordic Walking group showed decreased Plantarflexion angle and ROM. Second, Nordic Walking group showed decreased knee flexion angle and ROM. Third, Nordic Walking group showed increased hip joint movement. Fourth, Nordic Walking group showed higher active GRF but decreased loading rate from delayed Peak Vertical GRF time and increased impulse. Fifth, Nordic Walking group showed longer ground contact time. Through this study, we found that Nordic Walking showed higher stability and efficiency during gait than normal gait and that Nordic Walking may help people who have walking difficulties.

• 한국운동역학회지
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• 제20권4호
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• pp.421-427
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• 2010

The purpose of this study was to investigate the relationship between the quantitative analysis of biomechanical movement and the qualitative analysis of video software in order to evaluate for the walking movement. The fourteen collegiate students who agreed with the purpose and method of this study participated as subjects. The slow walking and fast walking of the subjects in the place of experiment were photographed, and calculated several mechanical factors. This empirical evidence from the experiment indicated the significant difference(p<.001) between each distant factors of the walking movement for both analyses methods, but there was no statistically significant difference between the spacial factors observed in the experiment. For more detail, no significant difference between the walking ratios that expressed the coordination between stride length and stride frequency was found. The findings also indicated the high coefficient of correlation(over r=.9) which supports higher explanation force for the biomechanical method and the Dartfish video software method. Therefore, if the data was gathered by using the proper experimental method, the video software method could be used just like the quantitative data of biomechanical method.

• 한국운동역학회지
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• 제17권3호
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• pp.209-215
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• 2007

The purpose of this study was to investigate gait factor and muscle activity depending on hiking poles-using. Eight healthy men volunteered for this experiment. Each of them performed down-hill walking with hiking poles-using and without poles at speed of 3.5km/h for 45 minutes on a treadmill. The treadmill was set 25% down-hill inclination. Kinematic data collected in 60Hz were recorded and analyzed by using 2D motion capture system to measure step time and step length so on. And the lower extremity muscle activities were simultaneously recorded in 1500Hz and assessed by using EMG. The statistical analysis was the paired t-test with repeated measures to compare between hiking poles-using and without poles. The level of statistical significance for all tests was .05. The results of this study were following : Step time was showed statistically different according to pole conditions. That is, the case of poles-using was longer than without poles in step time. Also, step length was showed statistically different between two conditions. Step length about trials with poles was longer than trials without poles. In the muscle activity, the case of all muscles was not showed statistical significance about pole conditions. However, in most muscles IEMG, there were some decreasing-trend relatively when hiking polesusing.