• 한국운동역학회지
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• 제27권3호
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• pp.205-210
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• 2017

Objective: The aim of the study was to investigate the age-related ability of dynamic balance recovery through perturbation response during standing. Method: Six older and 6 younger adults participated in this study. External perturbation during standing as pulling force applied at the pelvic level in the anterior direction was provided to the subject. The margin of stability was quantified as a measure of postural stability or dynamic balance recovery, and using principal component analysis (PCA), the regularity of the margin of stability (MoS) was calculated. Results: Our results showed that in the older adult group, 60.99% and 28.63% of the total variance were captured using the first and second principal components (PCs), respectively, and in the younger adult group, 81.95% and 10.71% of the total variance were captured using the first and second PCs, respectively. Conclusion: Ninety percent of the total variance captured using the first two PCs indicates that the older adults had decreased regularity of the MoS than the younger adults. Thus, the results of the present study suggest that aging is associated with non-regularity of dynamic postural stability.

• 한국운동역학회지
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• 제27권3호
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• pp.165-169
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• 2017

Objective: The Star Excursion Balance Test (SEBT) and Y-Balance Test (YBT) have been commonly applied to measure dynamic postural stability ability. These two tests are utilized interchangeably in various settings. However, they could in fact require different movements to assess dynamic postural stability, as one uses a platform and different measuring techniques than the other. The purpose of this study was to determine if there was a significant difference in the kinematic patterns in physically active population while performing the SEBT and the YBT. Method: Seventy participants performed in the Anterior (AN), Posteromedial (PM), and Posterolateral (PL) directions of the SEBT and the YBT. The kinematics of hip, knee, and ankle in sagittal plane was calculated and analyzed. Paired-sample t-tests were performed to compare joint angular displacement in the ankle, knee, and hip between the SEBT and the YBT. Results: Significant differences in angular displacement at the hip, knee, and ankle joints in the sagittal plane between performance on the SEBT and on the YBT were observed. Conclusion: Clinicians and researchers should not apply these dynamic postural control tasks interchangeably from one task to another. There appear to be kinematic pattern differences between tests in healthy physical active population.

• 한국운동역학회지
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• 제25권1호
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• pp.123-130
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• 2015

Purpose : The purpose of this study was to investigate the reliability of 3D-inertia measurement unit (IMU) based shoes in gait analysis. This was done with respect to the results of the optical motion capturing system and to collect reference gait data of healthy subjects with this device. Methods : The Smart Balance$^{(R)}$ system of 3D-IMU based shoes and Osprey$^{(R)}$ motion capturing cameras were used to collect motion data simultaneously. Forty four healthy subjects consisting of individuals in 20s (N=20), 40s (N=13), and 60s (N=11) participated in this study voluntarily. They performed natural walking on a treadmill for one minute at 4 different target speeds (3, 4, 5, 6 km/h), respectively. Results : Cadence (ICC=.998), step length (ICC=.970), stance phase (ICC=.845), and double-support phase (ICC=.684) from 3D-IMU based shoes were in agreement with results of optical motion system. Gait data of healthy subjects according to different treadmill speeds and ages were matched to previous literature showing increased cadence and reduced step length for elderly subjects. Conclusion : Conclusively, 3D-IMU based shoes in gait analysis were a satisfactory alternative option in measuring linear gait parameters.

• 한국운동역학회지
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• 제25권2호
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• pp.167-174
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• 2015

Purpose : The purpose of this study was to investigate the effects of loaded vertical jumps on the following vertical jumps and to find how long the transient effect of warm-ups would continue. Methods : Twelve healthy college male students, majoring in physical education, participated in this study voluntarily. They performed three sets of unloaded jumps (pre-jump, 5% post jump, and 10% post jump) and two sets of loaded jumps (5% and 10% loaded jumps) according to the counter-balanced order. At each set, three trials of maximal vertical jumps were performed by a 30 second interval between trials and a 3 minute break after warm-up jumps. Force platform and motion capturing system were used to record motions and ground reaction force. Results : Only 5% post-warm-up jumps ($48.29{\pm}2.06cm$) showed significant increase in the jump height compared with pre-warm-up jumps ($47.35{\pm}2.21cm$). The transient effects of loaded warm-ups disappeared 4 minutes after loaded jumps. Conclusion : Conclusively, a decent amount of loading (around 5% extra of body weight) during sport specific warm-ups would give a positive, transient effect on the performance of the vertical jump.

• 한국운동역학회지
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• 제25권2호
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• pp.219-229
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• 2015

Objective : The purpose of this study was to analyze EMG according to surface type and elastic band usage during the pilates Superman movement. Method : The subjects were 10 female university students with a mean age of 27. The independent variables were surface type (yoga mat, air filled equipment, elastic mat) and elastic band usage. In order to measure muscle activity, the Noraxon(USA) was used. Eight muscles (upper trapezius, lower trapezius, thoracic spine, lumbar spine, gluteus maximus, gluteus medius, biceps femoris, semitendinosus) activation were analyzed. For the statistical analysis, MANOVA, independent t-test and Scheffe test for the post-hoc via SPSS 20.0 was used. Results : The left and right upper trapezius muscle activities were significantly reduced when using the elastic bands. In addition gluteus medius muscle activities significantly increased with the elastic band as well. Conclusion : According to the usage of the elastic band and the different types of surfaces, different muscle groups were recruited. Elastic bands were found to have more activation on the gluteus medius muscle meanwhile there was less activation on the upper trapezius during the pilates Superman movement.

• 한국운동역학회지
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• 제25권2호
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• pp.207-218
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• 2015

Objective : The purpose of this study was to investigate the characteristics of Gam-ki (double-arm winding) depending on the emotion being expressed. Gam-ki is one of the basic movements of Korean traditional dance. Method : We selected three Korean traditional dancers who belong to National Dance Company of Korea. They were asked to express four different emotions (anger, joy, sadness, and neutral) while performing Gam-ki. We analyzed elapsed time and time ratio, size of movement, ground reaction forces and ground impulses. Results : During Gam-ki the elapsed time for each phase as well as for one cycle was longest when "sadness" was expressed then followed by "neutral" and then "angry" and "joy." Except for the ankle in/eversion, the ROMs of the lower limb joints seem not to be an emotion-characteristic factor. The ROMs of the upper limb joints were largest when "anger" was expressed. Neck rotation is associated with expressing negative emotions ("angry" and "sadness"). For medial-lateral GRF "angry"> "joy" > "neutral" > "sadness" was in order. Therefore, it can be regarded as a factor indicating the activity of the emotion.

• 한국운동역학회지
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• 제17권2호
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• pp.131-143
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• 2007

In this study, we are concluded like this : 5 men who are soccer player of P university in B city measure the Electromyography with an angle of motion according to kinesiotaping's application when practicing in-step kick. When exercising in-step kick, the change of realization of muscle load of lower limbs enhence Gastrocnemius Lateralis and Vastus Medialis in the section of backswing, and improve Tibialis Anterior, Vastus Medialis, Rectus Femoris prior to impact after back-swing. Before impact, it mainly impoved Tibialis Anterior, Vastus Medialis, Rectus Femoris. After impact, it generally improved Gastrocnemius Lateralis, Vastus Medialis. Average integral electromyography value, it was such a small difference(; the difference of the value in Tibialis Anterior, Rectus Femoris, Vastus Medialis) that we can't compare case of after taping than before. In Electromyography, in case of after taping was considerably decreased at Gastrocnemius Lateralis, there was statistically significant difference between before and after. It was a little increased, after taping than before at Knee angle. And degree was a little decreased at Ankle angle. But, It's so delicate difference, there was not statistically significant difference between before and after.

• 한국운동역학회지
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• 제17권2호
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• pp.83-91
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• 2007

This experiment studied the change in a human's control of his or her static posture by analyzing the stabilogram diffusion and, by using the said study, evaluated the control ability of different groups with different experiences. The postures had a rising requirement of heel-rise according to three conditions: heel-toe, ball, toe; the groups were divided into dance major student and non-dance majors. The results of the critical points according to posture did not show a direct relation with the change in postures that had a rising requirement of heel-rise. The diffusion coefficient(D) had greater stochastic activity for short-term regions that utilize open-loop controls without feedback than for long-term regions that used closed-loop controls with feedback to maintain balance. The directional results of the body undergoing disturbance showed that A/P direction's diffusion coefficient (D) was larger than that of M/L direction. Both feet's planar diffusion coefficients were a linear combination of the diffusion coefficients calculated for the x and y axis. In studying the different abilities to control posture between a dance major student and a non-dance majors, a comparison of open-loop control's diffusion coefficient(D) was effective, and dance major student had superior control ability to that of non-dance majors.

• 한국운동역학회지
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• 제17권2호
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• pp.75-82
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• 2007

The purpose of this study was to analyze and compare the effect of gait time on the gait patterns in elderly female OA and non-OA patients. The intensity of the subjects joint pain was surveyed by using WOMAC. Twelve subjects participated in this study. Measurements were taken for every the 10 minutes for 30 minutes after walking by a force plate. The following variables were recorded; double stance support time, Fx, Fy, Fx_time, Fz and so on. From the investigation of these variables the following was observed and concluded. The Fz values for the OA group was 1.01BW at the start and after 30 minutes was 1.04BW on the other hand the non-OA group's Fz1 was 1.08BW and 1.10BW. There was no significant difference calculated between the two groups and at the start and end of the experiment about all the variables. Therefore, it is concluded that there was no negative effect caused by walking for the 30 minutes and that it was an effective way of strengthen both respiratory and muscle function.

• 한국운동역학회지
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• 제17권2호
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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.