• 한국운동역학회지
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• 제22권3호
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• pp.295-304
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• 2012

This study, through biomechanical analysis, conducts a risk assessment of injury occurrence in ballet dancers while they perform running and jumping movements. The participants were nine female collegiate students majoring in ballet(age: $20.89{\pm}1.17years$; height: $160.89{\pm}7.01cm$; mass: $48.89{\pm}3.26$). Descriptive data were expressed as $mean{\pm}standard$ deviation(SD) for all variables. An independent t-test was conducted to determine how the following variables differed: duration time, position of the center of gravity, angle of the hip, torque of the hip, and muscle activity. All comparisons were made at the p<0.05 significance level. The results show that the jump time was two times longer than the run time in the duration time. The jump length was also longer than the run. The angle of the hip and the torque at the hip were higher in the right. The vastus medialis muscle was most frequently used. These findings demonstrate that participants' jumps may require more biomechanical variables for performance of better and more correct $jet{\acute{e}}$.

• 한국운동역학회지
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• 제28권3호
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• pp.187-191
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• 2018

Objective: The purpose of the present study is to investigate the effect of a muscle activity by applying the complex exercise method of sling in accordance with the provision of various vibration intensities for paraplegia-spinal cord injury. Method: The subjects of the study were 15 men in their 40s and 50s with lower limb disabilities and low potential risk, who were randomly divided into a sling exercise group (SG n=4), a sling with low frequency vibration group (SLVG n=4), a sling with mid-frequency vibration group (SMVG n=4), and a sling with high frequency group (SHVG n=4) in accordance with the provision of slings and vibration stimuli. The vibratory intensity provided was divided into low frequency (30 Hz), mid-frequency (50 Hz), and high frequency (70 Hz). The anterior deltoid (AD), the posterior deltoid (PD), the pectoralis major (PM), the upper trapezius (UT), the latissimus dorsi (LD), and the multifidus (MF) were measured to compare and analyze muscle activity. Results: The closed kinetic chain (CKC) exercise to the shoulder joint showed higher muscle activity in most muscles for the SMVG, and statistically significant differences in the anterior deltoid (AD), the pectoralis major (PM), and the multifidus (MF) in particular. Conclusion: The intermediate frequency (50 Hz) string vibration was the effective vibration stimuli for Closed kinetic chain (CKC) exercises.

• 한국운동역학회지
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• 제28권3호
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• pp.181-185
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• 2018

Objective: The purpose of this study was to investigate the effect of types of drive-in initial steps in basketball on technical factors, to provide basic information for the enhancement of basketball skill. Method: Ten men (age: $24.70{\pm}2.26years$; height: $181.00{\pm}5.72cm$; weight: $75.70{\pm}8.23kg$; career length: $10.00{\pm}3.59years$), each with a career length of over five years and no history of injury to the lower extremities within the prior six months, participated in this study. They were asked to perform four types of drive-in movements at $35{\sim}60^{\circ}$, wearing their own shoes, after running from a start line 5 m away and catching a basketball passed by an expert passer. The drive-in movements were measured by eight infrared cameras (Oqus 300, Qualisys, Sweden). Collected raw data were used to calculate total initial step time, displacement, velocity, center of mass (COM) height, and COM velocity. Results: Total initial step displacement and velocity of cross drive-ins (JC, SC) were greater than that of direct drive-ins (JD, SD; p < .05). COM velocity of cross drive-ins (JC, SC) was also greater than that of direct drive-ins (JD, SD; p < .05). Conclusion: Our results indicated that cross drive-ins, regardless of stop step type, are more effective than direct drive-ins. This is because cross drive-ins are technically bold due to less influence from walking violations and double dribble rules in basketball. However, using one-sided movement is too difficult to play in competitive game; therefore, basketball players should develop the ability to choose appropriate movement frequency.

• 한국융합학회논문지
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• 제9권10호
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• pp.423-432
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• 2018

본 연구는 볼링 선수의 상해 경험과 유형에 따라 상 하지 근력과 좌우 비대칭 차이를 살펴보고자 하였다. 본 연구 대상자는 상지 상해 경험 집단(upper body injury group, [UG], n=16)과 하지 상해 경험 집단(low body injury group, [LG], n=8), 상해 미경험 집단(non injury group, [NG], n=15)으로 선정하였다. 볼링 선수의 상 하지 근력은 Manual Muscle Tester 01165 (Lafayette Instrument Company, USA)로 등척성 최대 근력(Isometric strength)을 측정하였으며, 비대칭 지수(symmetry index, [SI])를 산출하였다. 그 결과는 다음과 같다. 하지 근력의 좌우 비대칭 지수는 엉덩관절의 신전과 외측회전 최대근력에서 상해 무경험 집단이 하지 상해 경험 집단에 비하여 통계적으로 크게 나타났다(p<.05). 위 결과를 통하여 하지 근력의 좌우 대칭이 하지 상해와 밀접한 관련이 있다고 판단되며, 상해 예방을 위해 하지 근력의 좌우 대칭 훈련이 필요할 것으로 판단된다.

• 한국운동역학회지
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• 제29권4호
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• pp.247-254
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• 2019

Objective: The goal of this study was to determine the center of pressure (CoP) complexity pattern in approximate entropy technique between genders at different conditions of running speed. Background: It is conducted to evaluate the complexity pattern of CoP in the increment of running speed to have insights to injury prediction, stability, and auxiliary aids for the foot. Method: Twenty men (age=22.3±1.5 yrs.; height=176.4±5.4 cm; body weight=73.9±8.2 kg) and Twenty women (age=20.8±1.2 yrs.; height=162.8±5.2 cm; body weight=55.0±6.3 kg) with heel strike pattern were recruited for the study. While they were running at 2.22, 3.33, 4.44 m/s speed on a treadmill (instrumented dual belt treadmills, USA) with a force plate, CoP data were collected for the 10 strides. The complexity pattern of the CoP was analyzed using the ApEn technique. Results: The ApEn of the medial-lateral and antero-posterior CoP in the increment of running speed showed significantly difference within genders (p<.05), but there were not statistically significant between genders at all conditions of running speed. Conclusion: Based on the results of this study, CoP complexity pattern in the increment of running speed was limited to be characterized between genders as an indicator to judge the potential injury and stability. Application: In future studies, it is needed to investigate the cause of change for complexity of CoP at various running speed related to this study.

• 한국운동역학회지
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• 제31권3호
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• pp.155-161
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• 2021

Objective: There is a lack of studies using the 3D-2D image registration techniques on the mechanism of a shoulder injury for ice hockey players. This study aimed to analyze in vivo 3D glenohumeral joint arthrokinematics in collegiate ice hockey athletes and compare shoulder scaption with or without a hockey stick using the 3D-2D image registration technique. Method: We recruited 12 male elite ice hockey players (age, 19.88 ± 0.65 years). For arthrokinematic analysis of the common shoulder abduction movements of the injury pathogenesis of ice hockey players, participants abducted their dominant arm along the scapular plane and then grabbed a stick using the same motion under C-arm fluoroscopy with 16 frames per second. Computed tomography (CT) scans of the shoulder complex were obtained with a 0.6-mm slice pitch. Data from the humerus translation distances, scapula upward rotation, anterior-posterior tilt, internal to external rotation angles, and scapulohumeral rhythm (SHR) ratio on glenohumeral (GH) joint kinematics were outputted using a MATLAB customized code. Results: The humeral translation in the stick hand compared to the bare hand moved more anterior and more superior until the abduction angle reached 40°. When the GH joint in the stick hand was at the maximal abduction of the scapula, the scapula was externally rotated 2~5° relative to 0°. The SHR ratio relative to the abduction along the scapular plane at 40° indicated a statistically significant difference between the two groups (p < 0.05). Conclusion: With arm loading with the stick, the humeral and scapular kinematics showed a significant correlation in the initial section of the SHR. Although these correlations might be difficult in clinical settings, ice hockey athletes can lead to the movement difference of the scapulohumeral joints with inherent instability.

• 운동과학
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• 제26권3호
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• pp.223-228
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• 2017

PURPOSE: This study investigated the protective role of high-intensity interval training against acute liver injury induced by D-galactosamine (D-Gal)/lipopolysaccharide (LPS). METHODS: A total of 30 male BALB/c mice aged 5-week were randomly assigned to high-intensity, interval training group (EX, n=10) or control group in cage (Non-EX, n=20) for 10 weeks. Peritoneal injection of D-Gal (700 mg/kg body weight) and LPS ($10{\mu}g/kg$ body weight) was applied to induce acute liver injury, and liver tissue was harvested 6 hours after the injection. Hematoxylin and Eosin (H&E) staining was used for liver histology. Real-time PCR was used to quantify expression of pro-inflammatory and anti-inflammatory genes in the liver. RESULTS: The liver histology showed that D-Gal/LPS treatment resulted in hepatic damage and increased number of neutrophils in conjunction with upregulation of hepatic IL-6 and $TNF-{\alpha}$ mRNAs and downregulation of hepatic $PPAR{\alpha}$ and SIRT1 mRNAs. On the other hand, the 10-week interval training resulted in a significant improvement in cardiorespiratory fitness assessed as run time to exhaustion on a treadmill. In addition, the interval training attenuated the D-Gal/LPS-induced liver damage and increased number of neutrophil in conjunction with downregulation of hepatic IL-6 and $TNF-{\alpha}$ mRNAs and upregulation of hepatic $PPAR{\alpha}$ and SIRT1 mRNAs. CONCLUSIONS: This study suggests that high-intensity interval training suppresses the D-Gal and LPS-induced acute liver damage and inflammatory responses.

• International Journal of Contents
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• 제13권3호
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• pp.59-64
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• 2017

The purpose of this study is to identify the types of injuries and the protective behaviors of soccer club members to prevent injuries, and promote health. Data was collected from 395 soccer club members from thirteen football clubs in Seoul and Gyeonggi province using question tool developed by researchers. Data analysis was performed using SPSS 23 for descriptive analysis and Chi-square test. The results showed that sport for soccer injuries was serious and medical expenses was significant. The demographic information showed that 50-year-old and over adults were vulnerable and had a disproportionate number of injuries. Those employees who helded administrative positions, white-collar and specialized jobs also experienced the high level of injury experience. Despite this many injuries, many respondents appeared to be lacking a protective actions, such as not wearing protective gear. It was critical for the club members to improve their knowledge and awareness of safe sports activities.

• Journal of Trauma and Injury
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• 제29권2호
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• pp.47-50
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• 2016

Transcatheter arterial embolization (TAE) for blunt hepatic injury in children is not common and is especially rare after damage control surgery (DCS). We report a successful TAE after DCS on a child for massive bleeding from the left hepatic artery due to a motor vehicle accident. The car (a sport utility vehicle) ran over the chest and abdomen of a 4-year-old boy. On arrival, initial vital signs were as follows: blood pressure, 70/40 mmHg; heart rate, 149/min; temperature, $36.7^{\circ}C$; respiratory rate, 38/min. After resuscitation, computed tomography was done, and a suspicious contrast leakage from a branch of the left hepatic artery and a spleen injury (grade V) were found. TAE was performed successfully after DCS for a liver injury.

• 한국운동역학회지
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• 제33권3호
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• pp.110-117
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• 2023

Objective: The purpose of this study was to find out kinematic and kinetic differences the lower extremity joint according to the landing type during vertical jump movement after jump landing, and to present an efficient landing method to reduce the incidence of injury in youth players. Method: Total of 24 Youth players under Korean Sport and Olympic Committee, who used either heel contact landing (HCG) or toe contact landing (TCG) participated in this study (HCG (12): CG height: 168.7 ± 9.7 cm, weight: 60.9 ± 11.6 kg, age: 14.1 ± 0.9 yrs., career: 4.3 ± 2.9 yrs., TCG height: 174.8 ± 4.9 cm, weight: 66.9 ± 9.9 kg, age 13.9 ± 0.8 yrs., career: 4.7 ± 2.0 yrs.). Participants were asked to perform jump landing consecutively followed by vertical jump. A 3-dimensional motion analysis with 19 infrared cameras and 2 force plates was performed in this study. To find out the significance between two landing styles independent t-test was performed and significance level was set at .05. Results: HCG showed a significantly higher dorsi flexion, extension and flexion angle at ankle, knee and hip joints, respectively compared with those of TCG (p<.05). Also, HCG revealed reduced RoM at ankle joint while it showed increased RoM at knee joint compared to TCG (p<.05). In addition, HGC showed greater peak force, a loading rate, and impulse than those of TCG (p<.05). Finally, greater planta flexion moment was revealed in TCG compared to HCG at ankle joint. For the knee joint HCG showed extension and flexion moment in E1 and E2, respectively, while TCG showed opposite results. Conclusion: Compared to toe contact landing, the heel contact landing is not expected to have an advantage in terms of absorbing and dispersing the impact of contact with the ground to the joint. If these movements continuously used, performance may deteriorate, including injuries, so it is believed that education on safe landing methods is needed for young athletes whose musculoskeletal growth is not fully mature.