• 한국응용과학기술학회지
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• 제36권2호
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• pp.424-433
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• 2019

본 연구는 양발 착지 시 성별에 따른 상해 경험이 무릎과 엉덩관절의 움직임 및 수직 지면반력에 미치는 영향을 분석하는데 목적이 있었다. 20대 남성 20명(상해 경험 8명, 비상해 경험 12명), 여성 20명(상해 경험 11명, 비상해 경험 9명)을 연구대상자로 선정하였다. 높이 45cm 박스에서 양발 착지를 통해 얻어진 운동역학적 변인을 Two-way mixed ANOVA를 실시하였으며, bonferroni adjustment를 이용하여 사후검증 하였다(p<.05). 본 연구결과 상해를 경험한 여성 그룹은 무릎 관절의 외반 및 내측회전 그리고 엉덩관절의 굴곡 및 외측회전 운동을 증가시켜 최대 수직 지면반발력의 감소를 유도할 수 있었던 것으로 판단된다. 상해를 경험하지 않은 여성 그룹의 경우 최대 무릎 굴곡각도가 가장 작게 나타났을 뿐만 아니라 엉덩관절의 굴곡과 외측회전 각도에서 가장 적은 수치를 나타내었고 최대 수직 지면반발력은 가장 높게 나타났다. 반면, 상해를 경험하지 않은 여성 INE 그룹의 경우 IE 그룹에 비해 상대적으로 무릎과 엉덩관절을 활용하지 못함으로서 높은 수직 지면반발력을 나타내었고, 이는 상대적으로 상해 위험성에 많이 노출되어 있음을 의미한다. 따라서 성별에 따른 상해 경험이 무릎과 엉덩관절의 운동과 최대 수직 지면반발력의 크기에 요인들에 영향을 주는 요인들임을 알 수 있었다.

• The Journal of Korean Physical Therapy
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• 제10권1호
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• pp.127-138
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• 1998

This study was carried out tn invstigate and compare biomechanical characteristics during free speed gait in hemiplegic patients after stroke who took therapeutic exercise by analyzing kinematic and kinetic data in the sagital plane and electromyographic data. Six patients($41\~69$ years old) and age-matched six volunteers in good health(51-61 years old) wire studied. The patients were sorted into two groups, depending on their self-speed of walking : fast speed group(3 patients) and slow speed group(3 patients). The results were as fellows. : 1. In spatio-temparal parameters, affected and unaffected side of fast group showed symetry but blew group showed asymetry of single limb support, opposite foot contact and stance phase (p<0.05). Compared with normal group, patient group showed slower velocity, shoter stride length and longer double limb support (p<0.05). 2. In the pelvic anterior tilt, patient group showed lower valued than normal group. It. In the ground reaction force-vertical force, fast group showed similar double peak gragh compared with normal group, butvslow group showed lower values without double peak (p<0.05).

• 항공우주시스템공학회지
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• 제11권6호
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• pp.17-25
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• 2017

항공기가 지상에서 주행할 때 지면과 타이어 사이에 걸리는 수직하중 정보는 마찰력, 횡력 계산 시 사용되는 등 항공기 거동에 있어서 주요한 변수이다. 그러나 실제 항공기 주행 시 실시간으로 수직하중 정보를 얻기 힘들고, 실제 시험에서 발생 가능한 비정상적 활주 상황을 방지하기 위하여 사전 해석을 통해 타이어 수직하중 및 항공기 지상 거동 특성을 예측해 볼 필요가 있다. 본 논문에서는 VI-Aircraft S/W를 이용하여 착륙장치 및 Full-Aircraft 모델을 구성하였고 조향 해석 및 활주시험 상황 모사 해석을 통하여 항공기 지상 거동 특성에 대하여 분석하였다.

• 한국운동역학회지
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• 제27권2호
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• pp.125-132
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• 2017

Objective: The aim of this study was to investigate the effect of targeted knee flexion angle on biomechanical factors of knee joint between upward and downward phases during the forward lunge. Method: Eight elderly subjects (age: $22.23{\pm}1.51years$, weight: $69{\pm}6.63kg$, height: $174.88{\pm}6.85cm$) participated in this study. All reflective marker data and ground reaction force during a forward lunge were collected. The knee joint movement and reaction force and joint moment at maximum knee flexion angle were compared by repeated measures one-way analysis of variance (ANOVA) (p<.05). The peak knee joint reaction force and joint moment between upward and downward phases were compared by repeated measures two-way ANOVA (p<.05). Results: The anterior and vertical knee joint movements, reaction force, and extensor moment of $80^{\circ}$ targeted knee flexion condition at maximum knee flexion angle was greater than both $90^{\circ}$ and $100^{\circ}$ conditions (p<.05). The $80^{\circ}$ knee flexed angle condition had greater peak joint reaction force and extensor moment compared with both $90^{\circ}$ and $100^{\circ}$ conditions between upward and downward phases during the forward lunge. Conclusion: As the targeted knee joint flexion angle increases, knee joint movement and kinetic variables become greater during the forward lunge exercise.

• 한국운동역학회지
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• 제17권1호
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• pp.17-27
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• 2007

It is essential for gait analysis to know the distance information. The purpose of this study was to investigate the effects of start and finish distance on the gait variable during walking. Six adolescent participated in this study. Start condition was given by six conditions.: walking forward from (1) one step, (2) three steps, (3) five steps, (4) ten steps, (5) one step after standing walk, and (6) three steps after standing walk, before contacting the force plate. Stop condition was given by four conditions. : stop after (1) one step, (2) two steps, (3) three steps, and (4) ten steps, passing force plate. Repeated measured one-way ANOVA was utilized for data analysis, and the significant level was set at .05. The largest change from the difference of gait velocity exists between the variables of ground reaction force. There were no significant differences in spatio-temporal and posture(angle) variables, as well as ground reaction force variables with walking over the three steps. There were significant differences in gait velocity, knee angle at heel contact, vertical impulse and ankle angle at toe off in short distance.

• 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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• 제29권3호
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• pp.137-143
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• 2019

Objective: Ligament laxity and hypotonia are characteristics of Down syndrome patients. The aim of this study was to compare the landing pattern between Down syndrome patients and typically developing subjects. To compare the landing pattern, variables related to ligament laxity and hypotonia i.e. vertical stiffness and lower extremities kinematics were investigated. Method: Five subjects with Down syndrome (age: $14.6{\pm}1.8years$, mass: $47.6{\pm}6.94kg$, height: $147.9{\pm}6.0cm$) and six able-bodied subjects (age: $13.2{\pm}0.4years$, mass: $54.7{\pm}6.7kg$, height: $160.1{\pm}9.8cm$) participated in this study. Results: The vertical displacement of the center of mass, vertical reaction force, leg stiffness and range of ankle angle range among Down syndrome patients were significantly different than typically developing group. The youth with Down's syndrome appeared to receive greater vertical impact force at landing than normal youth. Conclusion: The differences in the biomechanical characteristics suggest the delay in motor development among Down syndrome patients and an increased risk of injury to the lower extremity during movement execution such as drop landing.

• 대한물리의학회지
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• 제16권3호
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• pp.21-27
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• 2021

PURPOSE: This study examined the relationship between the severity of a hallux valgus (HV) deformity and the kinetic three-dimensional ground reaction force (GRF) through a motion analysis system with force platforms in individuals with a HV deformity during normal speed walking. METHODS: The participants were 36 adults with a HV deformity. The participants were asked to walk on a 6 m walkway with 40 infrared reflective markers attached to their pelvic and lower extremities. A camera capture system and two force platforms were used to collect kinetic data during gait. A Vicon Nexus and Visual3D motion analysis software were used to calculate the kinetic GRF data. RESULTS: This research showed that the anterior maximal force that occurred in the terminal stance phase during gait had a negative correlation with the HV angle (r = -.762, p < .01). In addition, the HV angle showed a low negative correlation with the second vertical maximal force (r = .346, p < .05) and a moderate positive correlation with the late medial maximal force (r = .641, p < .01). CONCLUSION: A more severe HV deformity results in greater abnormal translation of the plantar pressure and a significantly reduced pressure force under the first metatarsophalangeal joint.

• 한국임상수의학회지
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• 제20권4호
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• pp.504-507
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• 2003

Force plate analysis was used to describe the effect of acupuncture on right knee osteoarthritis (OA) in a seven-year-old hound breed dog weighing 27 kg. The acupuncture treatment was performed twice a week for 3 weeks. Ground reaction forces (GRFs) and subjective clinical scores in both hind limbs were obtained prior to and 72 hours after each treatment. Right vertical peak force was increased as the dog was acupunctured. Although their sensitivity was lower than that of the GRF data, the subjective clinical scores reflected an improvement. In addition, vertical peak force of normal left hind limb was also increased during this trial. These results indicate that gait analysis may be valuable objective method in future evaluation of acupuncture for OA of the stifle joint.

• 한국운동역학회지
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• 제26권3호
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• pp.265-272
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• 2016

Objective: The aim of this study was to analyze X-factor, triple X-factor, and the center of pressure (COP) according to the feel of golf driver swing. Method: For this research, 9 golfers from the Korea Professional Golfers' Association (age: $30.11{\pm}2.98yrs$, height: $178.00{\pm}8.42cm$, weight: $76.22{\pm}8.42kg$, experience: $10.06{\pm}3.11yrs$) were recruited to participate in the experiment. Twelve Motion Analysis Eagle-4 cameras were installed and an image analysis was conducted by using the NLT (non-linear transformation) method, and 2 units of Kistler type 5233A dynamometer were used to measure ground reaction force. The sampling ratio was set at 1000 Hz. The golfers each took 10 swings by using their own driver, and chose the best and worse feel from among 10 shots. A paired-sample t-test was used to analyze the results. Results: In regard to feel, no change in head speed, X-factor, and the triple X-factor's X-factor stretch, hip rise, and head swivel, was observed (p>.05). Regarding ground reaction force, a difference was observed between the top of the backswing (p<.05) and impact (p<.05) in the vertical force of the left foot. For COP, a difference was also observed between the mid backswing (p<.001), late backswing (p<.001), and top of the backswing (p<.05) for the right foot X-axis and Y-axis mid follow through (p<.01). Conclusion: It can be reasoned that, irrespective of feel, the head speed, X-factor and triple X-factor's X-factor stretch, hip rise and head swivel did not have an effect on drive distance for domestic golfers, and the vertical reaction force of the left foot and left-right movement span's pressure dispersal of the right foot had an increasing effect on drive distance.