• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.181-197
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• 2003

The Purpose of this study was to examine the kinematic analysis of the upper-limb motion of wheelchair basketball free throw shooting. Three-dimensional kinematic data were obtained from 8 male wheelchair basketball players performing a successful free throw. Players were divided into three groups, according to their IWBF classification(Group 1: 1 point players, Group 2: 2-2.5point players and Group 3:3.5-4 point players) Wheelchair basketball free throw motions were taken by video camera. The three-dimensional coordinates was processed by DLT. Players from Group 1 and 2 tended to release the ball from a lower height, with greater velocity and release angle. Players from Group 1 showed greater shoulder horizontal adduction and horizontal abduction angle, wrist ulnar flexion and radial flexion angle, and trunk angle. but players from Group 2 appeared lower shoulder abduction. Upper limb angular velocity showed most greatly in hands from Group 1, upperarm from Group 2, and forearm from Group 3.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.695-703
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• 2010

Objectives : The purpose of this study was to investigate the maxillofacial injuries of the sports players' and analyzing the concerned factor. Methods : The subject in this study were 290 sports players' enrolled in Jeolla region. SPSS statistics program(Version 12.0) was used to analyzed the collectde data, Chi-square test and percentage were used as the analysis technique. Results : 1. It was found that 63.8% of all respondents ever experienced trauma in sport activities and 28.6% experienced maxillofacial trauma. 2. In terms of traumatic causality, it was found that most of our respondents attributed the biggest cause of maxillofacial trauma to 'sport activities.' 3. However, it was found that only 12.1% of all respondents gave correct answers to question items about good medical treatment for traumatic odontoptosis. 4. It was found that less than half of all respondents ever faced information on maxillofacial trauma. Conclusions : This finding suggests that it is required to build up current orientation programs about maxillofacial trauma for our sport players. The maxillofacial trauma of sport players' is a important factor that degenerate the quality of the oral health and bring about the change of life style.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.55-63
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• 2012

The purpose of this study was to investigate the balance differences between skilled players and less-skilled players during Hakdariseogi motion of Keumgang Poomsae in Taekwondo. To achieve the study goal, total of 10 Taekwondo athletes; 5 skilled players(S, body mass: $67.0{\pm}5.7$ kg, height: $174.0{\pm}4.8$ cm, age: $20.0{\pm}2.0$ yrs) and 5 less-skilled players(LS, body mass: $73.0{\pm}4.9$ kg, height: $176.4{\pm}6.1$ cm, age: $20.8{\pm}1.3$ yrs) participated in this study. A three-dimensional motion analysis with 8 infrared cameras and one force plate whose sampling frequency as 30 Hz and 300 Hz, respectively, were performed. Participants' motion were divided into three phases which were preparation phase(P1), performing phase(P2) and maintaining phase(P3). The range and velocities of COP, the range and RMS of ground reaction torque and displacement between COM and center of BOS of each phase were computed. In this study, at P1 and P3 which were double and single stance, respectively, the range and M-L velocities of COP revealed significantly higher in LS compared with those of S(p<.05). At P2 which was single stance, LS indicated significantly higher in range of COP and ground reaction torque, and M-L velocities of COP than those of S(p<.05). The significantly shorter displacement between COM and center of BOS, however, was found in LS compared with that of S(p<.05). The results from our study indicated that S revealed more stable performance and a better posture control ability during performing Hakdariseogi motion.

• Geomechanics and Engineering
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• v.32 no.6
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• pp.627-637
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• 2023

Volleyball is an international sport with many fans. This sport has made significant progress in schools and clubs. Volleyball is suitable for all age groups and can be used in different environments. It has many social and physical benefits. During the game provides special physical training for the players and is considered one of the most exciting games. Another type of volleyball is beach volleyball, a beach sport and one of the Olympic sports held on the sand with the same rules as volleyball. This sport is usually played in coastal areas, especially with wide sandy beaches. Because this sport is played in open spaces, the players stay in this space for a long time and are exposed to dangerous ultraviolet radiation. It is a wavelength of light in the range of electromagnetic waves with a wavelength between 10 and 400 nm. This wavelength is shorter than visible light and more protracted than X-ray. Ultraviolet (UV) rays are naturally present in sunlight and include about 10% of all waves emitted from the sun's surface. Prolonged exposure to ultraviolet light causes acute and chronic damage to the skin and vision and even destroys the entire immune system. Different covers of the earth's surface reflect different amounts of UV rays. For example, snow cover, sand, and seawater surface reflect this radiation. Therefore, the health of volleyball players is in danger due to this harmful radiation. This work aims to introduce a type of clothing made of nanoparticles that can repel ultraviolet rays and protect beach volleyball players whose health is at risk from this radiation.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.296-302
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• 2010

The purpose of this study was to examine the oral injury experiences of sport players in a bid to raise awareness of the gravity of problems related to oral injuries and the necessity of mouth guards geared toward preventing mental, physical and economic loss triggered by oral injuries. The subjects in this study were 290 sport players. After their oral injury experiences and use of mouth guards were checked, the following findings were given: 28.6 percent had suffered an oral injury. But just 33.8 percent received education about how to cope with an oral injury. 93.4 percent had never used a mouth guard, and only 25.9 percent felt the need for that. And just 28.3 percent had an intention to use it. felt the need for that. And just 28.3 percent had an intention to use it. Concerning the impact of gender, the female players used more mouth guards. The players didn't use mouth guards a lot regardless of oral injury experiences and education about that, and there was no change in the way they looked at mouth guards, either. The findings of the study illustrated that sport players as well as non-players weren't aware of the importance of mouth guards, though sport players were exposed to the danger of an oral injury all the time. Not only players but non-players should learn about the seriousness of an oral injury, and the necessity of oral guards should be stressed to prevent it.

• Korean Journal of Applied Biomechanics
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• v.29 no.2
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• pp.53-60
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• 2019

Objective: The purpose of this study was to investigate the differences of smoothness and coordination of the fingers and upper extremities between skilled and non-skilled players during receiving the basketball. Method: Ten male recreational basketball players (age: $23.2{\pm}2.7yrs.$, career: $8.6{\pm}1.6yrs.$, height: $177.3{\pm}6.0$, weight: $72.9{\pm}8.5kg$) careering over five years and ten non-skilled males (age: $27.3{\pm}1.5yrs.$, height: $173.7{\pm}5.6$, weight: $73.2{\pm}12.6kg$) were participated in this study. Then, participants were asked to perform basketball receiving movement for ten times. The receiving movements were recorded by eight infrared cameras (Oqus 300, Qualisys, Sweden). The collected rad data were calculated to duration of basketball receiving, Jerk-Cost, CRP and CRP variability. Results: The CRP of MCP-Wr, Wr-El in skilled group were greater than non-skilled group (p<.05). The CRP variability of El-Sh in non-skilled group was greater than skilled group (p<.05). Conclusion: These results suggest that skilled players perform more effective movement for impact absorption from the basketball. Moreover, the skilled players have consistent movement patterns during basketball performance. Lastly, it is important to train finger sensation and cognitive ability of thrown basketball from the passer.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.421-427
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• 2011

The purpose of this study was to analyze the difference between male and female tennis players' two-handed backhand stroke and to provide basic data which helps precise and efficient instruction for the sake of precise postures, enhanced performances and skills. 5 male and 5 female university players were recruited as subjects, and the mean difference between the kinematic variables such as the time from backswing to impact and total swing time, racket head velocity, change of the center of body gravity in two-handed backhand stroke through three-dimensional motion analysis. The test data was analyzed by t-test, and the alpha level of ${\alpha}$=.05 was set for all tests of significance. The findings of the study were as follows; First, there was no difference in the time from backswing to impact and total time of

• Journal of Sport and Applied Science
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• v.5 no.3
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• pp.1-5
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• 2021

Purpose: The purpose of this study is to examine the relationship between the leadership style and performance of university athletes' leaders. Research design, data, and methodology: This study utilizes survey items constructed by reserach variables. Data were collected from college athletes of universities in Seoul and Gyeonggi-do, where sports teams are located. A convenient sampling method was used of non-probability sampling methods. A total of 314 responses were computed at statistic program, spss version 21.0. In specific, the study employed correlation, exploary factor analysis, mulple-regressions to test the effects of ledership types on performance. Results: As a result of an empirical analysis to examine the relationship between the leader's leader-ship style and the athletic performance of college athletes, it was found that the leader's leadership style had a significant effect on the college athletes' performance. Conclusions: A leader's leadership style is a very important factor for college athletes who enter the professional world after graduating from college. Therefore, coaches maintain a horizontal relationship with the players rather than a vertical one, and if a leadership style suitable for the players is applied, the players' performance will be better, and the development potential of players and teams will increase. Suggestions for future studies were discussed.

• Korean Journal of Exercise Nutrition
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• v.25 no.4
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• pp.10-16
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• 2021

[Purpose] The purpose of this study was to (i) assess hydration levels in elite male football players during a national team training camp before and during qualifying matches, (ii) evaluate the effect of coaching strategies for hydration based on feedback from hydration monitoring, and (iii) assess possible relationships between hydration status and training load or wellness markers. [Methods] Thirty-one male players (age 27±4 yrs; height 185±6 cm; weight 82.9±6.7 kg; body fat 10.4±2.3%) representing a national team from the Union of European Football Associations (UEFA) participated. The players were studied during three different national team training camps related to the UEFA Nations League tournament. Urine specific gravity (U_SG) was measured to assess hydration status. During all camps, the players were actively coached on improving strategies for hydration and given individual feedback on their test results. The training load was measured using GPS technology, and wellness questionnaires were completed. [Results] U_SG decreased progressively and significantly (p<0.005) during camp 1 and hydration status improved over the three camps, with fewer dehydrated and more well-hydrated players identified during the last part of camp 3. Significantly (p<0.05) higher U_SG values were observed 2 days prior to a match (MD-2) than on match day (MD); consequently, 52% of the players were dehydrated on MD-2 and only 6% on MD. No correlations were observed between hydration status and training load or wellness markers. [Conclusion] Dehydration is a challenge in elite male football, but continuous monitoring of hydration status and coaching on hydration strategies can lead to major improvements and reduce the degree of dehydration.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.193-204
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• 2002

The purpose of this study was to investigate the effect of martial art type and target height on the ground reaction force factors during Dollyuchagi motion. Data were collected using force plate. Five Taekwondo players and five Hapkido players were tested during Dollyuchagi motion to three different target heights(0.8, 1.2, 1.6 m). After analysis of kinetics using force plate data, maximum vertical ground reaction force was 1.62~2.44 BW, and impulse was $0.66\sim1.01 BW{\cdot}s$. Even though there was no difference for maximum ground reaction forces and impulse between Hapkido and Taekwondo, as target height was higher, impulse increased. Anterior-posterior and vertical ground reaction forces at kicking foot take-off were greater with target height, although there was no difference for medio-lateral force with target height. At impact there was significant difference for anterior-posterior ground reaction force between Hapkido and Taekwondo players. Taekwondo players' force (range, -0.23~-0.26 BW) was greater than Hapkido players's force (range, -0.08~-0.14 BW).