• Journal of The Korean Society of Integrative Medicine
• /
• v.8 no.1
• /
• pp.101-111
• /
• 2020

Purpose : The purpose of this study was to identify the comparison of the effects of manual therapy combined with exercise on range of motion (ROM), muscle strength, and functional performance in adolescent baseball players with internal impingement syndrome of the shoulder. Methods : The subjects were 30 patients diagnosed with impingement syndrome of the shoulder. Thirty subjects are randomly assigned to each 3 different groups; Group 1. (exercise group), Group 2. (exercise+mobilization; EMOB group), Group 3. (exercise+mobilization with movement; EMWM group). The interventions were performed three times a week for 4 weeks. The main outcome measures were goniometer, Biodex dynamometer, and Korean Kerlan Jobe shoulder-elbow (K-KJOC) scores. The ROM (external and internal rotation), muscle strength (external and internal rotation: 60 °/sec., 180 °/sec.), and functional performance were compared among the groups. Results : No significant difference was observed among the groups in the range of external rotation of the shoulder before and after the intervention, but the range of internal and total rotation was significantly increased in Group 2, 3 compared to Groups 1. Muscle strength of external and internal rotation (60 °/sec., 180 °/sec.) was not significantly different among Group 1, 2, 3, and functional performance was significantly increased in Group 2, 3 compared to Group 1. However, there was no significant difference between Group 2 and Group 3 in all measurements. Conclusion : An intervention with manual therapy such as EMOB and EMWM was more effective than exercise alone for rapid recovery from shoulder injury and improvement in functional performance. However, further efforts are needed to identify effects of specific interventions with manual therapy.

• The Korean Journal of Applied Statistics
• /
• v.21 no.3
• /
• pp.441-453
• /
• 2008

We analyzed Korean professional basketball and baseball players salary under the assumption that it depends on the personal records and contribution to the team in the previous year. We extensively used data visualization tools to check the relationship among the variables, to find outliers and to do model diagnostics. We used multiple linear regression and regression tree to fit the model and used cross-validation to find an optimal model. We check the relationship between variables carefully and chose a set of variables for the stepwise regression instead of using all variables. We found that points per game, number of assists, number of free throw successes, career are important variables for the basketball players. For the baseball pitchers, career, number of strike-outs per 9 innings, ERA, number of homeruns are important variables. For the baseball hitters, career, number of hits, FA are important variables.

• Journal of the Korea Convergence Society
• /
• v.12 no.8
• /
• pp.61-66
• /
• 2021

The purpose of this study was to investigate the relationship between vertical jump and lower extremity muscle strength of elementary school baseball players. This study subjects were conducted with a total of 40 subjects. Vertical jump was measured using a vertical jump gauge, and a hand held dynamometer was used to measure lower extremity muscle strength. For the measurement of lower extremity muscle strength, flexion·extension·adduction·abduction·internal rotaiton·external rotation of both hip joint, flexion·extension of both knee joint, dorsi flexion·plantar flexion of both ankle joint were measured. pearson's correlation analysis was used to analyze the correlation between vertical jump and lower extremity muscle strength. From these results, it was found that the stronger the leg muscles except for the plantar flexion, the higher the vertical jump was, indicating a positive correlation. In future studies, follow-up studies on the relationship between batting ability and vertical jump & lower extremity muscle strength are needed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.442-447
• /
• 2017

The purpose of this study was to establish norm-referenced criteria for the isokinetic strength of the elbow joint in Korean high school baseball players. Two hundred and one high school baseball players participated in this study, none of whom had any medical problem with their upper limbs. The elbow flexion/extension test was conducted four times at a speed of $60^{\circ}/sec$. The HUMAC NORM (CSMI, USA) system was used to obtain the values of the peak torque and peak torque per body weight. The results were presented as norm-referenced criterion valuesusing the 5-point scale of Cajori which consists of five stages (6.06%, 24.17%, 38.30%, 24.17%, and 6.06%). In the results of this study, the peak torques of the elbow (flexor and extensor?) at an angular velocity of $60^{\circ}/sec$ were $37.88{\pm}8.14Nm$ and $44.59{\pm}11.79Nm$, and the peak torque per body weight of the elbow (flexor and extensor?) were $50.06{\pm}8.66Nm$ and $58.28{\pm}12.84Nm$, respectively. The reference values of the peak torque and peak torque per body weight of the elbow flexor and extensor were setat an angular velocity of $60^{\circ}/sec$. On the basis of the results analyzed in this study, the following conclusions were drawn. There is a lack of proper studies on the elbow joint strength, even though the most common injury in baseball players occurs in the elbow joint. Therefore, we need to establish a standard muscle strength in order to prevent elbow joint injuries and improve their performance. The criteria for the peak torque and peak torque per body weight established here in will provide useful information for high school baseball players, baseball coaches, athletic trainers and sports injury rehabilitation specialists in injury recovery and return to rehabilitation, which can beutilized as objective clinical assessment data.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.1
• /
• pp.25-35
• /
• 2013

This study examined 24 right-handed amateur baseball players. Twelve who had played baseball for more than 6 years were grouped as skilled players, while 12 who had played for 1-3 years were the unskilled player group. The swing motion was divided into four event phases: stance, backswing, impact, and follow-through. The mean and maximum plantar pressure, center of pressure, and ground reaction force were measured during each event phase. The mean and standard deviations for each variables were calculated and differences were validated with the independent sample t-test. A p-value <0.05 was considered statistically significant. The results were as follows. 1)The ideal stance is a stable, balanced position with more than 65% of weight on the right foot. There was significant difference in mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significant. 2)The effective backswing of a skilled player is comprised a rightward shift in weight to build maximum energy. More than 90% of the weight was on the right foot. There was a significant difference in the mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significantly. 3) For an effective impact, a rapid shift in weight to the left foot is essential, so that a power hit is obtained. Significant difference in the mean and maximum plantar pressures of both feet were observed. 4)Follow-through requires wight balance, more on the right than the left, without leaning leftward. There was no significant difference in the mean or maximum plantar pressure. 5)The center of plantar pressure should move from the center of the foot to the toe. 6)The analyses of the ground reaction force suggest that a good swing involves a gradual shift in weight to the right side and a rapid leftward shift at impact. Good balance, with the center of gravity on the right side at follow-through, is also required.

• Journal of The Korean Society of Integrative Medicine
• /
• v.12 no.1
• /
• pp.139-150
• /
• 2024

Purpose : Scapular dyskinesis, it have been shown to be common in overhead athletes and has been associated with RC muscle strength. Posterior shoulder tightness (PST) has been suggested as an important factor causing scapular dyskinesis. Therefore, rehabilitation programs should focus on a posterior shoulder stretch combined with scapular stabilization exercise (PSSE) intervention. Determine the effects of posterior shoulder stretch combined with scapular stabilization exercise on the rotator cuff (RC) muscles strength, functional strength ratio (FSR), range of motion (ROM), and pain. Methods : 30 adolescent baseball players participated and subjects were allocated PSSE group (n=15) or the SSE group (n=15). Both group performed a 6-weeks intervention and measured of isokinetic peak torque/body weight (PT/BW) of concentric external rotator (CER), eccentric external rotator (EER), concentric internal rotator (CIR), eccentric internal rotator (EIR), FSR, ROM, and pain. Results : After 6 weeks PSSE, significant increase CER PT/BW (+6.02±4.76 %), EER PT/BW (+5.39±4.22 %), EER to CIR ratio (+.17±.16), and internal rotation ROM (+15.08±3.57 °). Whereas, significant decrease EIR to CER ratio (-.14±.18), external rotation ROM (-12.00±6.94 °), and GIRD (-17.41±2.84 °) compared with pre-intervention. No significant difference of isokinetic PT/BW of CIR and EER post-intervention. In the SSE group showed no significant difference all measurements for isokinetic PT/BW, FSR, and ROM post-intervention. The pain was significant improve both PSSE group (-3.25±1.60) and SSE group (-2.83±1.85) post-intervention. Conclusion : Both the PSSE and SSE interventions led to more pain relief. However, only the PSSE group showed ROM, CER, EER PT/BW, and FSR improvements. These results might suggest that the PSSE intervention is a more effective program for improving RC muscle strength and balance, in particular, concentric and eccentric ER muscle strength, FSR and can expect to prevent shoulder injuries in adolescent baseball players with scapular dyskinesis.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.1
• /
• pp.221-228
• /
• 2018

Big data is an important keyword in World's Fourth Industrial Revolution in public and private division including IoT(Internet of Things), AI(Artificial Intelligence) and Cloud system in the fields of science, technology, industry and society. Big data based on services are available in various fields such as transportation, weather, medical care, and marketing. In particular, in the field of sports, various types of bio-signals can be collected and managed by the appearance of a wearable device that can measure vital signs in training or rehabilitation for daily life rather than a hospital or a rehabilitation center. However, research on big data with vital signs from wearable devices for training and rehabilitation for baseball players have not yet been stimulated. Therefore, in this paper, we propose a system for baseball infield and outfield players, especially which can store and analyze the momentum measurement vital signals based on big data.

• Journal of the Korean Data and Information Science Society
• /
• v.23 no.2
• /
• pp.285-298
• /
• 2012

This research deals with a relationship between the performance of Korean professional baseball players and their annual salaries. It is based on the sabermetrics, which measures the performance of baseball batters in a refined way. We collect the records of batters of eight professional baseball clubs during the season 2009 and 2010. Then, we calculate every index of the sabermetrics. Principal component analysis is used for examining the relationship between those indexes of sabermetrics and annual salary for the next year. In general, batters who show higher performance get more salary. The result of this research can be useful in order to reach an agreement on salary between a player and his club partner.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.1
• /
• pp.41-47
• /
• 2019

In this paper, we propose a new batter evaluation model that reflects the skill of the opponent pitcher in Korean professional baseball. The model consists of evaluation factors such as Run Value, Contribution Score and Ball Consumption considering the pitcher grade. These evaluation factors are calculated as different data. In order to include the evaluation factors having different characteristics into one model, each evaluation factor is weighted and added. The genetic algorithms were used to calculate the weights, and the data were based on the 2016 records of Korea Professional Baseball and the salary data of the players of 2017. As a result of calculation of the weight, the weight of the Run Value was high and the weight of the Contribution Score was very low. This means that when calculating the annual salary, it reflects much of the expected score according to the batting result of the batter. On the other hand, the contribution score indicating the degree to which the batting result contributed to the victory of the team according to the state of the economy is not reflected in the salary or point system.

• The Korean Journal of Coaching Psychology
• /
• v.7 no.3
• /
• pp.197-225
• /
• 2023

In this study, the impact of Competitive Anxiety on Cognitive Appraisal and Performance Confidence among Amateur baseball players was investigated, as well as the mediating role of Cognitive Appraisal in this relationship. Furthermore, the moderating effect of Character Strengths related to positive psychology on the relationship between Competitive Anxiety and Cognitive Appraisal was explored, dividing these Character Strengths into six virtues. To conduct this research, an online survey was administered to 201 Amateur baseball players aged 19 and above. The result of this study are as follows. First, it was found that the association between Performance Confidence and Competitive Anxiety is mediated by Cognitive Appraisal. Second, Character Strengths showed a moderating effect in the relationship between Cognitive Appraisal and Competitive Anxiety. Thirdly, statistical significance was shown for the moderated mediation effects. Specifically, it was established that values like Transcendence and Justice would considerably moderate the relationship. Notably, the degree to which Cognitive Appraisal declines as a result of Competitive Anxiety was found to be mitigated by Transcendence and Justice Character Strengths. In conclusion, based on the results of this study, implications, limitations were discussed.