• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_1
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• pp.257-268
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• 2024

Soccer is type of sport that carries a high risk of injury. Injury is not only cause in the unlucky soccer carrier and also team performance as well as financial effects can be worse since soccer is a team-based game. The duration of recovery from a soccer injury typically relies on its type and severity. Therefore, we conduct this research in order to predict the probability of players injury type using machine learning technologies in this paper. Furthermore, we compare different machine learning models to find the best fit model. This paper utilizes various supervised classification machine learning models, including Decision Tree, Random Forest, K-Nearest Neighbors (KNN), and Naive Bayes. Moreover, based on our finding the KNN and Decision models achieved the highest accuracy rates at 70%, surpassing other models. The Random Forest model followed closely with an accuracy score of 62%. Among the evaluated models, the Naive Bayes model demonstrated the lowest accuracy at 56%. We gathered information about 54 professional soccer players who are playing in the top five European leagues based on their career history. We gathered information about 54 professional soccer players who are playing in the top five European leagues based on their career history.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.1
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• pp.77-90
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• 2015

When enjoying sports activities with friends or others, sportswear has symbolic meanings to express and expect self-concept. Sports players sometimes have trouble when they feel embarrassed by their low skills or care about other people too much. Therefore, researchers tried to find out which feature of sports players affects dependence on brand sportswear along with the effect of wearing conspicuous sportswear on wearer when sports players have a conflict based on Solomon's symbolic interactionism. We proposed that role knowledge and attention to social comparison information (ATSCI) influenced people to depend on and use brand sportswear that influences a reflexive evaluation. Finally, we suggested that a changed self-concept would exert influence commitment to sports. A quantitative study was conducted employing an online survey of 121 people by convenient sampling. In this process, Google Docs was to create the online survey and to collect responses by participants. In data processing, via SPSS 21.0 version for Windows, exploratory factor analysis, Cronbach's ${\alpha}$, ANOVA, t-test, discriminant and regression analysis were conducted to study the relationship between variables. The finding provided evidence that low role knowledge and high ATSCI create high dependence on brand sportswear and influence people to buy sportswear. When people bought and wore a brand sportswear, they evaluated themselves as professional sports players who were more committed to sports. This study confirmed that brand sportswear was useful for sport players to change self-evaluation and enjoy sports.

• 한국체육학회지인문사회과학편
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• v.54 no.5
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• pp.581-592
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• 2015

This research was fairness in sport and power is how they form and change through historical discussion on the sport's doping and ran afoul of fairness Explored in match-fixing in relationship with power, the product of the problems of human desires. First, doping and exploration of power. The history of doping in sports, history as long as it existed before. Medication is ruler of the players can't or don't conform with authority between the pair formed a relationship, where, in accordance with the victory of a temptation for wealth and fame and vested interests and desire, is personal, Society and country ranging and widely is committed. In particular, power of expression is reflected well reflected in the sport in the Cold War era and, in those days was wrong thinking and practices are still truly understands the connection between doping and anti-doping. Second, match-fixing and exploration of power. Also in the history of sport as doping, match-fixing, always existed. Sport and fairness of match-fixing in relation to artificial sources, and well decide the outcome of which ended with sport, not an issue connected to gambling and other crimes, And that's another sport and bring about a vicious circle of even turn into a row. The reason for this match fixing in power part of the formation of capital and profits for the exact cause has developed that further threatens the fair sport. Thus, in fairness, and relations of power in sport doping and match-fixing is historically very meaningful and, further research and discussion is needed. Buried the materialistic values of sport doping and match-fixing, nothing is being tolerated and other researchers' power as the elements of the pie grow only by sport only No one can guarantee that only satisfied if we hold a bright future of sport.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.145-156
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• 2007

The purposes of this study were to investigate kinematic parameters of racket head and upper extremities during squash back hand stroke and to provide quantitative data to the players. Five Korean elite male players were used as subjects in this study. To find out the swing motion of the players, the land-markers were attached to the segments of upper limb and 3-D motion analysis was performed. Orientation angles were also computed for angular movement of each segment. The results were as follows. 1) the average time of the back hand swing (downswing + follow-through) was 0.39s (0.24 s + 0.15 s). 2) for each event, the average racket velocity at impact was 11.17m/s and the velocity at the end of swing was 8.03m/s, which was the fastest swing speed after impact. Also, for each phase, 5.10m/s was found in down swing but 7.68m/s was found in follow-through. Racket swing speed was fastest after the impact but the swing speed was reduced in the follow-through phase. 3) in records of average of joints angle, shoulder angle was defined as the relative angle to the body. 1.04rad was found at end of back swing, 1.75rad at impact and it changes to 2.35 rad at the end of swing. Elbow angle was defined as the relative angle of forearm to upper arm. 1.73rad was found at top of backswing, 2.79rad at impact, and the angle was changed to 2.55rad at end of swing. Wrist angle was defined as the relative angle of hand to forearm. 2.48rad was found at top of backswing, 2.86rad at impact, and the angle changes to 1.96rad at end of swing. As a result, if the ball is to fly in the fastest speed, the body has to move in the order of trunk, shoulder, elbow and wrist (from proximal segment to distal segment). Thus, the flexibility of the wrist can be very important factor to increase ball speed as the last action of strong impact. In conclusion, the movement in order of the shoulder, elbow and the wrist decided the racket head speed and the standard deviations were increased as the motion was transferred from proximal to the distal segment due to the personal difference of swing arc. In particular, the use of wrist (snap) may change the output dramatically. Therefore, it was concluded that the flexible wrist movement in squash was very important factor to determine the direction and spin of the ball.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.89-99
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• 2006

The study were to assess technical factors between the high score group and the low score group, from the subjects of 16 male national gymnasts, and to analyze the kinematical characteristic and main technical cause on technique of Akopian's 3D motion analysis of the male vaulting game in 2001 classification championship. The result of this study is this. There were not so much difference between the two groups in term; of the time of board contact, pre-flight, and total performance, but it takes shorter time when the players who are in the high point group take down the board, and they take long time for post-flight(p<.01). The high point group has a longer perpendicular distance in the moment of horse taking off, 0.05m on the average, than the low point group. The high point group shows 0.16m higher on the average than the other group in term; of the height of post-flight(p<.01). In the phase of board contact, the range of horizontal velocity at board take on were $7.66m/s{\sim}7.33m/s$, but there weren't significantly statistic differences between two groups. The hight score group were 0.68m/s faster than the low point group at the horizontal velocity at board take off event(<.05). About the average horizontal velocity of deceleration, AG1(-1.95m/s) reduces the speed more than AG2(-1.57m/s)(p<.05). And the hight score group were 0.37m/s faster than the low point group at the vertical velocity at horse take off event(<.05). When board taking off, the projectile angle of com were $38.7{\sim}37.8degree$ on the average. the comparative groups show almost same results. When horse taking off, the HPVy of the high point group were 37.6 degree which were a little higher than the low point group. The angular velocities of the players who takes on the horse with a right hand and then takes off with a left hand in the high point group were 14.97rad/sec, 10.82rad/sec in the low point group. However, the angular velocity of the players who takes on the horse with a left hand and then takes off on a right hand with the high point group were 14.97rad/sec, 15.56rad/sec in the low point group.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.115-124
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• 2002

The purpose of this study is to analyze the ground reaction force of arm landing on arm and leg during sports aerobics. Subjects of this study were total 10 players of 5 males and 5 females who have are domain sports aerobics medalists more than the third place in national tournaments. The subjects jumped between the two ground reaction force analyzers, while landing their right hand on the front platform(#1) and their right leg on the rear platform(#2), and the data frequency was set to 200Hz. Findings of this study are as follows; More than 3 times of impact peak force of vertical reaction force acted on arm joint than on leg joint. And, when ground reaction force on foot increased, ground reaction force on hand decreased. 3 impact peaks of curve of ground reaction force were found - Impact Peak 1 incurred on the time the palm lands on the ground, Impact Peak 2 absorbing shock secondarily on wrist joint, and Active Peak incurred on the time of holding the weight while pushing out the severly bent elbow joint.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.95-103
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• 2006

The purpose of this study was to analyze a change of maximal grip forces and EMG of agonists in upper extremity of 8 professional Ssirum players according to Satbar-grip patterns, to elucidate prime agonist muscles, contribution rate of each muscle, and a difference on EMG in upper extremity. one-way ANOVA(RM) performed for average and maximal values of each player after standardization and statistical significance was set as p<.05. The result includes the following: the highest grip force was A type with a statistic significance using one-way ANOVA and Duncan's comparison between A and C type. In summary the highest grip force was exerted on extension in the wrist than flexion in all grip types. Average and maximal values of biceps brachii and brachioradialis muscles were statistically significant and ones of flexor carpi ulnaris and extensor capi ulnaris were not.

• 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.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.1-12
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• 2003

This study was performed to provide normative isokinetic strength of knee muscles of middle school non-athletic and athletic populations for rehabilitation and pre-season screening for injury prevention. Seven non-athletic subjects and 8 hockey players participated in this investigation. Each subject was tested at speeds of $60^{\circ}/sec$, $180^{\circ}/sec$, and $300^{\circ}/sec$. The free weight of lower leg was measured at speed of $60^{\circ}/sec$ to take gravity effect Into consideration when peak torque of knee muscles occurred. The results showed that the relative peak torque production of knee flexors did not change but the relative peak torque of knee extensors decreased significantly. Mamstring/quadriceps ratios increased mainly due to significant decreases in knee extensors torque production. No significant differences were found between groups. The hamstring/quadriceps ratios for both groups were significantly lower when the gravity effect was not eliminated.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.165-172
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• 2007

The purpose of this study was to examine the effects of the result of hardship performance of the propulsion speed on the flying carmel spins during a Figure Skating. The subjects were five the korea national representative players. Kinematic variables were analyzed 5frame of the excursion phase by the three-dimensional motion analysis system(60Hz). The obtained conclusion were as follows: In this study, during the propulsion classify two groups as "type I" the acceleration patterns S3, S4 and "type II" the uniform velocity group S1, S2, S5. The results of percentage comparative analysis between type I and type II can be summarized as below: the height of jump(24%), the height of COM(25%), the maximum speed of Roundhouse Kick(21%), the judging technical score(18%), the flight time(13%), the velocity of spins(4%), the distance of flight(-6%) Analysis of the results on performance variables, the velocity pattern of the type I showed comparatively excellence than that of type II.