• Journal of Digital Convergence
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• v.15 no.7
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• pp.479-487
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• 2017

The purpose of this study was to identify the most influential soccer players by appling social network analysis. The subjects were the German national soccer team and the Korean national soccer team participated in the 2016 Brazil World Cup. The pass collected data provided by FIFA were analyzed by social network analysis using the Ucinet6 program and pass success rate. The results are as follows. First, the soccer player with a lot of passes had a high connection centrality in pass-through networks and high proximity. Second, the German national soccer team has appeared key players as Phillip Lahm and Kroos player, and a key player of the Korean national soccer team was Ki,S.Y. Third, the German national soccer team's quantitative indicator value of proximity center and pass success rate appeared higher than the Korean national soccer team's.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.406-412
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• 2024

In order to investigate trends in youth soccer research, this study selected 18 prior literature published in domestic KCI-registered journals related to youth soccer over a three-year period from 2021 to 2023 as research subjects. Previous research on youth soccer was analyzed by year, journal, research method, and subject, and the results are as follows. First, the number of papers published on topics related to youth soccer was the highest at 9 in 2021. Second, it was found that youth soccer-related research was conducted in various sports-related academic journals. Third, quantitative research methodology took up a higher proportion of 83% than qualitative research method. Fourth, studies targeting youth soccer players were the highest at 50%, followed by coaches and parents of youth players.

• The Journal of Korean Physical Therapy
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• v.28 no.4
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• pp.254-258
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• 2016

Purpose: This study was conducted to identify the effects of dual task training on balance and functional performance in high school soccer players with functional ankle instability. Methods: Twenty high school soccer players with functional ankle instability were randomly assigned to a single task training group and a dual task training group. One participant who did not participate regularly in the training was excluded. The single task training group (n=9) received balance training on an unstable surface. The dual task training group (n=10) received balance training on an unstable surface and had to catch thrown balls during the balance training. Both groups were trained for 4 weeks, 3 days a week. The balance and functional performance of both groups was measured before and after training. Balance was measured using an anterior-posterior and medio-lateral balance. Functional performance was measured based on a figure-of-8 hop test, up-down hop test, and a single hop test. All data were analyzed by repeated two-way ANOVA tests. Results: A time by group interaction effect was not observed in the medio-lateral balance test, figure-of-8 hop test, or single hop test (p>0.05). A time by group interaction effect was observed in the anterior-posterior balance and up-down hop test (p<0.05). Conclusion: These results suggest that dual task training improved balance and functional performance better than single task training for some items.

• Proceedings of the IEEK Conference
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• 2000.11d
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• pp.33-36
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• 2000

To create a more realistic soccer game derived from TV images, we are developing an image synthesis system that generates 3D image sequence from TV images. We propose the method for the team and the pose recognition of players in TV images. The representation includes camera calibration method, team recognition method and pose recognition method. To find the location of a player on the field, a field model is constructed and a player's field position is transformed by 4-feature points. To recognize the team information of players, we compute RGB mean values and standard deviations of a player in TV images. Finally, to recognize pose of a player, this system computes the velocity and the ratio of player(height/width). Experimental results are included to evaluate the performance of the team and the pose recognition.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.8 no.2
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• pp.31-43
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• 2002

The subjects of this study were 15 woman soccer players and 15 untrained woman students at H-Cheju University. Each subject was measured on the muscle strength and peak torque of knee extensors and knee flexors with isokinetic load ($60^{\circ}$/sec, $180^{\circ}$/sec). The results were as follows: 1. There was no significant difference between right and left leg strength measured isokinetically in each group. 2. The peak torque of knee extensors and flexors was significantly higher in scoccer players than untrainded students (p<0.001). 3. For the angle of knee joint showing the highest peak torque, there was significant difference between soccer players and untrained students in knee extensors(p<0.05) and right flexors (p<0.01). 4. For knee H/Q ratio, there was significant difference between two groups(p<0.05). 5. For the total work and average power at $180^{\circ}$/sec, there was significant difference between two groups in knee extensors(p<0.001) and flexors(p<0.01). 6. In soccer players at $60^{\circ}$/sec, there were significant correlations between peak torque and height and between peak torque and weight.(p<0.001). 7. For the muscular contraction velocity at $60^{\circ}$/sec, there was significant difference between two groups in flexors (p<0.01). 8. For the muscular indurance at $180^{\circ}$/sec in extensors and flexors, there was no significant difference between two groups(p<0.05). In conclusion, there were significantly higher in peak torque, contraction velocity, knee joint's angle with the highest peak torque, H/Q ratio, total work and average power in woman scoccer player than general students. But there was no significant difference in muscular endurance. Soccer performance is based on the various components including muscular endurance that is one of the most important components. So it is necessary that the training method to improve the various components (especially including muscular endurance) should be done.

• Journal of Nutrition and Health
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• v.36 no.7
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• pp.729-735
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• 2003

This study was performed to evaluate the effect of iron supplement for 4 weeks on iron status, immunity, and antioxidant status of national female soccer players (n = 25). This study was performed at summer hard training period right before competition. A single blind design was used to divide the subjects into iron-supplement (IS) or placebo group (P). Iron-supplement group was supplemented with iron (40 mg/d) for 4 weeks. The mean age of the subjects was 23.3 $\pm$ 2.5 years old. Mean height and body weight of the subjects were 164.4 $\pm$ 5.7 em and 57.4 $\pm$ 4.6 kg, respectively. The mean carrier as soccer player was 11.0 $\pm$ 2.6 years and mean training time was 7.0 $\pm$ 1.3 hr/day. The mean hemoglobin, hematocrit, total iron binding capacity and ferritin concentrations before iron supplementation were not different between two groups. After 4 weeks of summer training and iron supplementation, serum ferritin level was significantly increased only in IS group after supplementation. Mean corpuscular volume and total iron binding capacity were significantly decreased in both groups. Meanwhile, hemoglobin and red blood cell count were significantly lowered only in placebo group. The IgM concentration increased significantly in both groups, but IgG concentration had increasing tendency only in IS group (p < 0.064). Therefore, iron supplementation during hard training period may be helpful to improve work capacity of the athletes by improving ferritin status and humoral immune responses.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.391-395
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• 2011

To investigate the anticipatory effect on landing patterns during side-cutting maneuver, thirteen healthy female elite college soccer players participated in this study. Three-dimensional knee kinematics, effective mass and correlation between both these were measured and analyzed using a motion analysis and force plates. Each testing session included anticipated tasks, $45^{\circ}$ side-cutting tasks (AC), followed by a set of unexpected side-cutting (UC) in a random order. Knee flexion/extension, valgus/varus and internal/external rotation angles and effect mass were compared by using paired t-test. Also, correlation analysis was performed to identify the relationship between knee angles and effective mass. Effective mass during UC was greater than that during AC. Effective mass and maximum knee flexion angle were positively correlated during AC and not during UC. Based on the relationship between effective mass and knee flexion angle in AC, shock absorption can be controlled by knee joint flexion in pre-predicted movement condition. However, effective mass can not be controlled by knee flexion in UC condition. The unexpected load affects were more irregular on the knee joint, which may be one of the injury mechanisms of anterior cruciate ligament (ACL) in female soccer players.

• Tuberculosis and Respiratory Diseases
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• v.38 no.4
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• pp.379-383
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• 1991

To evaluate the effect of intensive training on ventilatory functions in soccer players, comparisons of various ventilatory parameters were made before and after 5-5.5 months of intensive training. The subjects were 15 members of a university soccer team with mean age and career of 19.9 and 8.3 years, respectively. Ventilatory parameters studied were those obtained by the analyses of forced expiratory volume and maximal expiratory flow-volume curves, as well as spirometric measurements of VC and MVV. After intensive training, volume parameters, such as VC, FVC and $FEV_{1&3}$ as well as flow parameters, effort-dependent and effort-independent, such as MVV, FEF200-1200, FEF25-75%, PEF, FEF25%, FEF50%, FEF75% showed significant increase. However, when the observed values of flow parameters were volume-adjusted to FVC, the differences before and after intensive training became insignificant. This suggests that enhanced ventilatory functions in soccer players after intensive training are primarily due to increase in FVC caused by increase in respiratory musle strength.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.357-367
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• 2016

In this study, we examined the impact on balance ability and jump performance of soccer players with functional ankle instability using virtual reality based neuromuscular posture control fusion training. Soccer players were divided into 15 people of virtual reality-based neuromuscular posture control fusion training group and 15 people of common treadmill training group and performed for 30 minutes three times a week for 8 weeks. In order to evaluate the balance of ability, using biorescue, it measured surface area, whole path length, limit of stability. In order to measure jump performance, it measured counter movement jump with arm swing and standing long jump. The results showed the statistically significant difference in the balance comparison of surface area, whole path length, limited of stability and the jump performance comparison of counter movement jump with arm swing, standing long jump. As a result, virtual reality-based neuromuscular posture control fusion training was found to be more effective to improve its balance ability and jump performance than common treadmill training.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.30 no.2
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• pp.13-26
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• 2024

Background: The most common form of injury in soccer is a hamstring strain. Eccentric bias exercises are crucial for reducing injury risk and improving sprinting performance. The purpose of this study was to compare a 4-week hip-dominant hamstring strengthening exercise program (HDE) with a knee-dominant hamstring strengthening exercise program (KDE) in youth soccer players. Method: The sample (n=31) was randomly divided into two groups: HDE (n=17) and KDE (n=14), with soccer players in HDE performing hip joint-dominant hamstring strengthening exercises and those in KDE performing knee joint-dominant hamstring strengthening exercises. Each intervention was conducted three times per week for four weeks. The outcome measures included the hamstring strength test (isometric strength test, eccentric strength test), knee joint range of motion (90/90 active knee extension; AKE) test, lower limb function test Y-balance test and Agility T-test. Results: Following the intervention, both groups showed significant improvement in isometric and eccentric hamstring strength on both dominant and non-dominant sides (p<.05). The AKE test showed significant improvement in the dominant leg (p<.05) and non-dominant leg only in KDE. The agility test significantly improved in HDE (p<.05). There was a slight improvement in the Y-balance test score; however, the difference was not statistically significant. There were no differences between the two groups in the values before, and after the intervention for all items. Conclusion: The hip-dominant and knee-dominant hamstring strengthening exercise should be coordinated and used based on the environment during hamstring injury prevention training.