• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.173-180
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• 2014

The purpose of this study was to investigate the effect of combined exercise on injury risk factors of lower extremity during landing. Ten sports talented athletes participated in this study. Sports talented athletes participated in a combined exercise (sports talented exercise, coordination) for 16 weeks. A three-dimensional motion analysis was performed using eight infrared cameras (sampling rate of 100 Hz), one force plate, and electromyography system (sampling rate of 1000 Hz) during landing. Kinetic, and kinematics analysis including average impulsive force, angle of lower extremity, vertical stiffness, onset of muscle activation were calculated by Matlab2009a software. Paired t-test was performed at alpha=.05. The average impulsive force in landing phase was not statistically significant (t=-.748, p=.474). The hip joint angle was more decreased in post test compared to pre test (E1: t=2.682, p=.025, E2: t=5.609, p=.000, E3: t=2.538, p=.032). The knee joint (E1: t=-.343, p=.739, E2: t=1.319, p=.220, E3: t=.589, p=.570) and ankle joint (E1: t=.081, p=.937, E2: t=.784, p=.453, E3: t=.392, p=.704) angle were tended to decrease after combined exercise. The vertical stiffness was tended to decrease after combined exercise (t=1.972, p=.080). Onset of quadriceps femoris (t=.698, p=.503) and medial gastocnemius (t=1.858, p=.096) were tended to be faster than biceps femoris (t=-.333, p=.747) after combined exercise. Although thses findings were not statistically significant except on a hip joint angle, risk factors of lower extremity such as joint angle, vertical stiffness and onset of quadriceps femoris, medial gastrocnemius were positively changed after the combined exercise but an additional training for improved onset of biceps femoris would be required in the future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1628-1633
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• 2017

The purpose of this study was to identify the difference and correlation in elbow joint maximal flexion strength according to measurement methods and characteristics of muscular contraction, and to develop the predictive equation of elbow joint maximal flexion strength for the optimal exercise intensity setting and accurate measurement. Subjects were 30 male university students. Elbow joint maximal flexion strength of isokinetic contraction, isometric contraction at $75^{\circ}$ elbow joint flexion position, isotonic concentric 1RM, manual muscle strength (MMT) were measured with isokinetic dynamometer, dumbbell, and manual muscle tester. Pearson's r, linear regression equation, and multiple regression equation between variables were calculated. As a result, the highest value was isometric contraction. The second highest value was MMT. The third highest value was isokinetic contraction. 1RM was the lowest. Predictive equations of elbow joint maximal flexion strength between isometric and isokinetic contraction, between isometric contraction and 1RM, among isometric contraction, 1RM, and body weight were developed. In conclusion, 1RM and isokinetic elbow joint maximal flexion strength could be seemed to underestimate the practical elbow joint maximal flexion strength. And it is suggested that the developed predictive equations in this study should be useful in criteria- and goal-setting for resistant exercise and sports rehabilitation after elbow joint injury.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.175-187
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• 2006

The purpose of this study was to find the relationship between Achilles tendon angle, angular velocity from 2D cinematography utilized to easily analyze the functions of shoes, ankle joint moment, knee joint moment, and hip joint moment from 3D cinematography utilized to predict the injury. Also, this study was to provide the optimal standard to analyze the injury related to the shoes. Subjects in this study were 30 university male students and 18 conditions (2 types of running speed, 3 of midsole hardness, 3 of midsole height) were measured using cinematography and force platform. The results were as following. 1) Hip joint abduction moment was effected by many variables such as running speed, midsole height, maximum achilles tendon angle, ground reaction force. 2) Knee joint rotational moment in running was approximately 1/10 - 1/4 times of the injury critical value and eversion moment was approximately 1/4 - 1/2 times of the injury critical value. 3) Ankle joint pronation moment in running was 1/3 - 1/2 times of the injury critical value. 4) Knee joint rotational moment was found to be irrelevant with maximum achilles tendon angle or angular velocity. 5) Pronation from running was thought to be relevant to rather eversion moment activity than rotational moment activity of knee joint. 6) Plantar flexion abductor of ankle showed significant relationship with the ground reaction force variable. 7) When the loading rate for ground reaction force in passive region increased, extensor tended to be exposed to the injury. Main variables in biomechanical analysis of shoes were impact absorption and pronation. Among these variables, pronation factor was reported to be relevant with knee injury from long duration exercise. Achilles tendon angle factor was utilized frequently to evaluate this. However, as the results of this study showed, the relationship between these variables and injury relating variable of knee moment was so important. Studies without consideration on this finding should be reconsidered and reconfirmed.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.461-467
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• 2018

The purpose of this study was to identify the analysis of the difference between accident type and injury type on ski resort. In order to achieve this purpose, a total of 522 persons recorded in the safety accident logs of two ski resorts located in Gyeonggi - do in 2016-2017 winter season by the purposeful sampling method. Frequency analysis, chi-square test were executed using SPSS Statistics 21.0 Version. As the results, the following conclusion was derived. First, injury part differ statistically and significantly according to both socio-demographic variables(lesson experience). Second, injury type differ statistically and significantly according to both socio-demographic variables(event, lesson experience, event${\times}$age, lesson experience${\times}$gender). Lastly, both injury part and injury type differ statistically and significantly according to Slope course.

• Korean Journal of Applied Biomechanics
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• v.30 no.2
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• pp.185-195
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• 2020

Objective: The purpose of this study was to identify recent domestic and international research trends regarding shoes carried out in biomechanics field and to suggest the direction of shoe research later. Method: To achieve this goal of research, the Web of Science, Scopus, PubMed, Korea Education and Research Information Service and Korean Citation Index were searched to identify trends in 64 domestic and international research. Also, classified into the interaction of the human body, usability evaluation of functional shoes, smart shoe development research, and suggested the following are the suggestions for future research directions. Conclusion: A study for the coordination of muscle activity, control of motion and prevention of injury should be sought by developing shoes of eco-friendly materials, and scientific evidence such as physical aspects, materials, floor shapes and friction should be supported. Second, a study on elite athletes in various sports is needed based on functional shoes using new materials to improve their performance along with cooperation in muscle activities and prevention of injury. Third, various information and energy production are possible in real time through human behavioral information, and the application of Human Machine Interface (HMI) technology through shoe-sensor-human interaction should be explored.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 1995.05a
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• pp.20-20
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• 1995

American football is currently played in 29 Universities in Korea, It is a contact sport where injuries are inevitable. This study was undertaken to determine the incidence and the anatomical distribution of injury based on evaluation of Yonsei University American football team. A total 74 injuries was reported among 77 players Knee, ankle and hand were vulnerable to injury. Operations were performed on $9(12.2\%)$ of the injuries. Catastrophic injuries can occur in this sport, but none has happened in Yonsei University team during the 20 years for which the sports has been practised. The frequency of injuries and their profile resemble those in US-based studies so it is suggested that the precautions and preventive measures recommended in the USA should be applied and followed in Korea.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.273-281
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• 2019

This study aimed to qualify the amount of movement during game-based training and competition by using a GPS and to identify the non-contact injury risk in lower extremities for female field hockey enrolled in Korean national team. A total of 52 players were participated in this study and their GPS data collected during training and competition were averaged for 1 week and 4 weeks. And then, an injury risk in lower extremities was calculated for each category of the amount of movement in GPS variables that were related to non-contact injury. In forwards, the injury risk was the lowest in the moderate-low category of total distance covered and repeated high-intensity effort bout and the high category of high intensity distance for 1 week, but the risk decreased as the amount of high intensity distance increased for 4 weeks. In midfielders, the injury risk was the lowest in the low category of total distance covered, high intensity distance, repeated high-intensity effort bout and deceleration bout for 1 week.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.31-38
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• 2008

The purpose of this study was to investigate the effects of anterior cruciate ligament (ACL) injury prevention program on the ground reaction force during the rebound in female highschool basketball players. Sixteen highschool female basketball players (ages 16 to 18 years) were participated in this study. Eight of these players participated in a 8-week ACL injury prevention program. Before and After ACL injury prevention program, initial peak value(%BW), maximum peak value(%BW), impulse(%BW sec), and loading rate(N/sec) were measured in the players. The experiment group after ACL injury prevention program showed significant decreased initial peak value, impulse, and loading rate.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2007.03a
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• pp.13-14
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• 2007

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.259-274
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• 2005

The purpose of this study was to compare the kinematic and kinetic parameters of lower extremity joints between novice and experienced sports aerobic dancers during two heights of depth jumps. Four male dancers were participated in this study and they performed 40cm and 60cm height depth jump three times, respectively. Four ProReflex MCU cameras (100frame/sec) and a Kistler force plate (1000Hz) were used for data collection. The results indicated that the duration of contact phase of experienced group was shorter than that of novice group regardless of jump height. For minimum angle of hip, knee, and ankle joints, the novice group had tendency to decrease the angle but the experienced group had increased the joint angle with jump height. There was no difference of total ground reaction force between the groups but the reaction force had tendency to increase with jump height. Thus, this study implied that repetition of jump and landing may induce joint related injury and further study such as. EMG analysis of lower extremity can be needed to verify the relationship between injury and ground reaction force.