• Journal of Korean Orthopaedic Sports Medicine
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• v.11 no.2
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• pp.75-81
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• 2012

Purpose: To evaluate the ultrasonographic (US) findings in both shoulders of asymptomatic high school baseball players and compare with healthy control. Materials and Methods: 42 individuals (age: $7.6{\pm}1.2$ years) participated in this study. We recruited two groups of high school male baseball players, 14 pitchers and 18 fielders without shoulder pain for recent 6 months as well as one control group of 10 untrained healthy high school students who were age-matched. Ultrasound measurements of thickness of the biceps and supraspinatus tendon and acromio-humral distance (AHD) at $0^{\circ}$ abduction were taken in dominant and nondominant shoulders. Results: On US examination, subacromial bursa effusion was observed in 7 of the dominant shoulders and in 2 of the nondominant shoulder of 32 baseball players and in none of the asymptomatic controls. The thickness of the biceps and supraspinatus tendons and AHD in both shoulders were significantly greater in the baseball players than in the controls (p<0.05). We also found that the biceps and supraspinatus tendon thickness and AHD of the dominant shoulder were significantly greater than the non-dominant shoulder in baseball players (p<0.05), but there were no differences between pitchers and fielders and between healthy controls. Conclusion: Subacromial effusion could be found even in the asymptomatic stage and the thickness of the biceps and supraspinatus tendons and AHD were significantly greater in the baseball players than in the healthy controls. Our data is useful reference guide for the ultrasonographic diagnosis of shoulder pathologies occurring in high school baseball players.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.539-547
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• 2016

The study is conducted to investigate the prevalence of a yips phenomenon in high school baseball players and provide the basis of its origin and an effective treatment intervention. Therefore, we survey 320 high school baseball players registered at Korea Baseball Association, excluding poorly answered 30 questionnaires. Utilizing PASW 20.0, the analysis of yips experiences and a coping method is carried out with descriptive statistics and ratio analysis. The results from the process above are as follows. The ratio of high school baseball players who experience yips reaches 64%, which is significantly high; experiencing yips, they have both physical and psychological problems; although they would have psychological trainings, few of them work, which implies that the discussion on yips prevention and coping methods for high school baseball players is imperative.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.5 no.2
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• pp.81-88
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• 2012

Purpose: To evaluate the ultrasonographic (US) findings in both shoulders of asymptomatic high school overhead athletes and compare with healthy control. Materials and Methods: 33 individuals (age: $17.5{\pm}1.4$ years) participated in this study. We recruited two groups of high school male athletes, 13 baseball and 10 volleyball players without shoulder pain for recent 6 months as well as one control group of 10 untrained healthy high school students who were age-matched. Ultrasound measurements of thickness of biceps and supraspinatus tendon and acromio-humral distance (AHD) at 0o abduction were taken in dominant and nondominant shoulders. Results: On US examination, subacromial bursa effusion was observed in 5 of the dominant shoulders and in 1 of the nondominant shoulder of 23 overhead athletes and in none of the asymptomatic controls. The thickness of the biceps and supraspinatus tendons and AHD in both shoulders were significantly greater in the athletes than in the controls (P<0.05). We also found that the thickness of the biceps and supraspinatus tendon and AHD of the dominant shoulder were significantly greater than the non-dominant shoulder in overhead athletes (P<0.05), but there were no differences between baseball and volleyball players. Conclusion: Subacromial effusion could be found even in the asymptomatic stage overhead athlete and the thickness of the biceps and supraspinatus tendons and AHD were significantly greater in the overhead athletes than in the healthy controls. Our data is useful reference guide for the ultrasonographic diagnosis of shoulder pathologies occurring in overhead athletes.

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