• Clinics in Shoulder and Elbow
• /
• v.25 no.3
• /
• pp.188-194
• /
• 2022

Background: Medial elbow laxity develops in throwing athletes due to valgus forces. Medial elbow instability in professional, collegiate, and high school athletes is well documented; however, the medial elbow of young throwing athletes has received less attention. This study investigated the medial elbow and common flexor tendon during applied elbow valgus stress of youth baseball players. Methods: The study included 15 participants. The medial elbow width and thickness of the common flexor tendon were measured on ultrasound images. Results: No significant side differences in medial elbow width or common flexor tendon were found at rest or under applied valgus stress. At rest, the medial elbow joint width was 3.34±0.94 mm on the dominant side and 3.42±0.86 mm on the non-dominant side. The dominant side increased to 3.83±1.02 mm with applied valgus stress, and the non-dominant side increased to 3.96±1.04 mm. The mean flexor tendon thickness was 3.89±0.63 mm on the dominant side and 4.02±0.70 mm on the non-dominant side. Conclusions: These findings differ from similar studies in older throwing athletes, likely because of the lack of accumulated stress on the medial elbow of youth throwing athletes. Maintaining elbow stability in young throwing athletes is a vital step to preventing injury later in their careers.

• Journal of the Korean Society of Physical Medicine
• /
• v.16 no.1
• /
• pp.33-39
• /
• 2021

PURPOSE: This study compared the body composition according to the sport of short-distance and middle & long-distance athletes to identify the factors that affect the body composition. METHODS: Forty-eight athletes selected as youth national athletes in 2019 participated in the study. The study participants measured the length of the lower extremities, body composition, and anaerobic ability. An independent sample t-test was conducted to compare the body composition according to the event. In addition, the Pearson correlation was performed to identify the factors that influence the body composition. RESULTS: The leg length of the Short and Middle & long-distance athletes were similar (p = .584). On the other hand, there were differences in the body fat percentage (p = .001), lean percentage (p = .001), and BMI (p = .001). In addition, the body fat percentage was correlated with the lean body mass (r = .419) and BMI (r = .447). Furthermore, the lean body mass was correlated with the BMI (r = .849) and the peak power (r = .662) and mean power (r = .686) of the anaerobic capacity. Moreover, the BMI was correlated with the peak power (r = .490) and mean power (r = .543) of the anaerobic capacity. The peak power of the anaerobic ability was correlated with the mean power (r = .931). CONCLUSION: The body composition differed according to the sport. The body fat percentage correlated with the lean body mass and the BMI. The lean body mass correlated with the BMI, peak power of anaerobic ability, and mean power. The BMI correlated with the anaerobic capacity.

• Journal of the Korea Convergence Society
• /
• v.11 no.10
• /
• pp.125-131
• /
• 2020

This study sought to reduce the risk of fractures in elite youth taekwondo athletes to find out the relationship between bone mineral density which are used as indicators of early diagnosis of osteoporosis and cardiorespiratory functional capacity which is an indicator of performance and sports injury the harmful to athletes. The Pearson product-moment correlation was performed to investigate the correlation between bone mineral density, cardiorespiratory functional capacity, and sports injury. The bone mineral density and cardiorespiratory functional capacity, sports injury were examined the relationship using the Simple Linear Regression. The bone mineral density were correlated with the ventilation (r=.388), and VO2max (r=.478). Bone mineral density was correlated with sports injury (r=-.292). When the bone mineral density increased by .002 and .006, the ventilation (p=.001) and VO2max (p=.006) increased by about 1. In addition, when the bone mineral density decline by .016, the sports injury increased by about 1. Improving athletes' bone mineral density can prevent sports injury, and it can be used as a sports injury prevention program in the future.

• Nutrition Research and Practice
• /
• v.17 no.4
• /
• pp.762-779
• /
• 2023

BACKGROUND/OBJECTIVES: Mediterranean diet is an environmentally friendly and healthy diet model. The diet offers many vegetables, fruits, nuts, and olive oil to consumers. In addition, it provides moderate amounts of fish and chicken, smaller quantities of dairy products, red meat, and processed meat. The Mediterranean diet has a high anti-inflammatory and antioxidant content, and it causes many physiological changes that can provide a physical performance advantage. This study examined the effects of a 15-day menu, which was planned using foods with a low acid load within the Mediterranean diet rules, on the exercise performance, lactate elimination, anthropometric measurements, and body composition. SUBJECTS/METHODS: Fifteen professional male athletes between the ages of 13 and 18, who were engaged in ski running, were included in the experimental study. Dietary intervention was applied for 15 days. The athlete performances were evaluated by applying the vertical jump test, hand grip strength, 20 meters shuttle run test, and Borg fatigue scale. After the shuttle run test (every 3 min for 30 min), blood was drawn from the finger, and the lactate elimination time was calculated. Performance and lactate measurements, body analysis, and anthropometric measurements were taken before and after dietary intervention. RESULTS: The vertical jump height and hand grip strength increased after the intervention (P < 0.05). The test duration, total distance, the number of shuttles, and maximum oxygen consumption parameters of the shuttle run test increased (P < 0.05). After the intervention, the athletes' perceived fatigue scores decreased in several stages of the shuttle run test (P < 0.05). The lactate elimination time and athlete's body composition were similar in repeated measurements (P > 0.05). In the last measurements, the upper middle arm circumference decreased while the height of the athletes increased (P < 0.05). CONCLUSIONS: These results show that the Mediterranean diet is a safe and feasible dietary approach for aerobic performance and strength increase.

• Korean Journal of Applied Biomechanics
• /
• v.33 no.3
• /
• pp.85-93
• /
• 2023

Objective: This study examined differences in joint kinematics and movement variability of lower extremity between adolescent athletes with and without lateral ankle sprain (LAS) history during drop vertical jump. Method: Fourteen adolescent athletes with LAS history and 14 controls participated in this study. The independent variable was group while dependent variables were 3D joint kinematics and movement variability of hip, knee, and ankle joint. Ensemble curve analyses were conducted to identify differences in movement strategies between two groups. Results: The LAS group showed that greater eversion during jump phase compared with the control group. Additionally, less movement variability was found in the LAS group during the pre-landing and jump phases in ankle and hip joints compared with the control group. Conclusion: The LAS group may adapt the environmental constraints by reducing the movement variability in ankle and hip joints. However, training programs focusing on recovery of ankle function should be emphasized after LAS because excessive pronation for prevention of LAS during the jump phase may result in reduced performance.

• Journal of Digital Convergence
• /
• v.10 no.11
• /
• pp.395-402
• /
• 2012

This study has been conducted to design and implement smart phone-based application which can keep records effectively to improve athletes' ability. To boost their performance, they need to receive training as realistic as possible. As a way to do that, training should be performed with some fitness equipments, sporting apparatus, facilities, and conditions. However, it is also possible to improve their ability by motivating athletes with checking and recording their performance. This study ascertains that using scoring records actually motivates athletes when comparing the result of youth basketball team using the records keeping system with that of not using it. Accordingly, smart phone-based records keeping application has been designed and developed. Also, through a survey targeting athletic coaches who have used the system, training efficiency has been measured and it turns out that it actually motivates athletes to improve their abilities.

• Korean Journal of Applied Biomechanics
• /
• v.30 no.2
• /
• pp.155-163
• /
• 2020

Objective: This study to identify the mechanism of head impact that occurs during youth soccer game with regard to head injuries in sports. Method: Ten male subjects (age: 10.0±2.0 yrs.) were participated during 10 soccer practices spread out over a time period of 10 weeks. During each soccer game, the participants agreed and wore the X-Patch (wireless accelerometer, gyroscopes). The X-Patch records the head impact mechanics, such as peak linear acceleration (PLA), peak rotational acceleration (PRA), peak rotational velocity (PRV), Head Injury Criterion (HIC), and the location of impact. Results: A total of 501 impacts to the head were measured over the 10 soccer games, PLA 17.8±10.4 g, PRA 3168±2442 rad/s²; PRV 16.1±10.6 rad/s; HIC 11.7±34.2. The severity of impact was classified into 3 ranges; low 10~39 g (482 impacts); medium 40~69 g (17 impacts); and high >69 g (2 impacts). There are no significant differences in PLA and HIC (p=0.08, p=0.15), however PRA and PRV show the differences (p<.05) between each of the participants. For the analysis comparing between the soccer games, there are no significant differences in PLA, PRA, PRV and HIC (p=0.11, p=0.13, p=0.14, p=0.05). Conclusion: Our results indicated that there were significant differences between athletes, especially in terms of rotational acceleration, whereas there were significant differences in linear and rotational based variable between each of the soccer games. Although the vast majority of impacts were below 39 g there were 2 potentially dangerous impacts above 69 g. It is important that future research continuous to measure head impact mechanics during soccer to help understand head injury mechanisms to ensure the safety of athletes.

• Korean Journal of Applied Biomechanics
• /
• v.32 no.2
• /
• pp.43-48
• /
• 2022

Objective: The purpose of this study was to verify the effectiveness among simulating ski jumping trainings by comparing with actual ski jump. Method: Three healthy youth national athletes were recruited for this study (age: 13.70 ± 0.9 yrs, height: 169.30 ± 0.9 cm, jumping caree: 5.3 ± 0.9 yrs). Participants were asked to performed ski jumping with 3 simulating and one actual situation. A 3-dimensional motion analysis with 5 channels of EMG was performed in this study. Muscle activations of Rectus Femoris [RF], Tibialis Anterior [TA], Thoracis [TH], Gluteus maximus [GM], and Gastronemius [GL] were achieved with sampling rate of 2,000 Hz during each jump. Results: In the case of S1 in the actual jumping motion, the deviation of the muscle activity peak did not appear each trial, and the jump timing was consistent. For S2, the timing of the muscles peak activation which can maintain the posture of the upper body and ankles appeared at the beginning. In the case of S3, the part maintaining the ankle posture at the beginning appeared, but it could be expected that it would progress in the vertical direction due to the activation of GL at the time of jumping. Conclusion: The muscle activation peak before the take-off point showed a different pattern for each athlete, and individual differences were large. In addition, it was attempted to confirm the actual jump with simulation jump, and it was found that not only the difference in patterns but also the fluctuations in the timing of each muscle activation peak were large.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.8
• /
• pp.5198-5206
• /
• 2015

The purpose of this study was to examine the effect of social support from friend, senior junior, and coach on student-athletes' stress and deviant behavior. By using convenience sampling method of non-probability sampling, a total of 350 student-athletes from D and G city were selected. Of 217 copies of the questionnaire gathered, 35 were discarded owing to having excessive missing values. Thus, by analysing a total of 182 surveys with structural equation modeling through AMOS 20.0 statistics program, this study found the followings. First, social support has a negative influence on stress. Second, stress has a positive influence on deviant behavior. Third, social support has a negative influence on deviant behavior mediated by stress.

• Journal of the Korean Applied Science and Technology
• /
• v.40 no.6
• /
• pp.1350-1362
• /
• 2023

This study aims to identify the influence of the image of Chinese Taekwondo leaders at university on the athlete's grit, psychological state, and performance. The analysis is expected to contribute to the quality development of Chinese universities' Taekwondo program in the future. For this study, a population was selected from athletes at a university in Henan Province, China. The samples were taken by convenience sampling method. Of the 380 questionnaires retrieved, a total of 365 were used to process the results, excluding 15 insincere responses or missing values. The collected data were conducted by frequency analysis, correlation analysis, reliability analysis, exploratory factor analysis and multiple regression analysis using SPSS 23.0 program. The results of this study are as follows. First, the sub-factors of the leader image, the leader's social activities and vocational awareness, qualities, tasks and roles, were found to have a significant impact on the grit of taekwondo athletes. Second, the sub-factors of the leader image, the leader's social activities and vocational awareness, qualities, attitudes, tasks and roles had significant impact on the phychological state of taekwondo athletes. Third, social activities, vocational awareness, quality, and attitude of the leader, which are the sub-factors of the leader image, have a significant impact on the performance of taekwondo athletes.