• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.301-309
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• 2015

Objective : The purpose of this study was to describe the correlation between the activity of the muscles of upper and lower limbs of a golf driver swing according to shoulder injury. Method : The subjects were 18 professional golfers (7 male in KPGA and 11 female in KLPGA). Using surface electromyography, we evaluated muscle activities during the golf drive swing. Surface electrodes were used to record the level of muscle activity in the left Deltoid(MD), Triceps Brachii(TB), Pectoralis(PM), Trapezius(UT), Rectus Femoris(RF), Vastus Medialis Obilique(VMO), Biceps Femoris(BF), Gastrocnemius(GCM) muscles during the golfer's swing. The golf swing was divided into five phases: take away, forward swing, acceleration, early follow through, late follow through. Results : The results can be summarized as follows: MD, VMO had statistically significant difference in take away phases, GCM had statistically significant difference in acceleration phases, MD, PM, VMO had statistically significant difference in early follow through phases, PM had statistically significant difference in late follow through phases, Conclusion : Muscle activity of the 8 muscles(Deltoid, Triceps Brachii, Pectoralis, Trapezius, Rectus Femoris, Vastus Medialis Obilique, Biceps Femoris, Gastrocnemius) along the shoulder damage or absence of has shown that they are organically connected to each of the phases.

• 한국체육학회지인문사회과학편
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• v.58 no.2
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• pp.405-416
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• 2019

This study aimed to identify the efficiency of short track-related sports injury prevention program consisted of muscle strength and neuromuscular training on non-contact injury incidence and characteristics in knee and ankle joints and low back for elite short track speed skaters. Twenty-five short track athletes who belonged to G-City Team were participated in this study from Nov. 2017 to Jul. 2018. Information on their sports injuries occurred were collected and injury prevention program was applied in their warm-up every training sessions and competition. Also their symptom-level of knee and ankle joint and low back were measured by using OSTRC overuse injury questionnaire and Cumberland ankle instability(CAIT). The injury incidence rate after application of prevention program was 2.79 injuries/1,000 hour exposures(HEs), which was lower than before (3.04 injuries/1,000HEs). The OSTRC score (30.89±28.34 and 23.84±23.61, respectively) in knee and low back after application of prevention program were lower than before (58.47±26.77 and 52.36±21.55, respectively), and the CAIT score (13.47±6.07) in ankle joint after application of program was higher than before (16.26±7.28), which means that their symptom-level was alleviated with sports injury prevention program. In conclusion, the sports injury prevention program designed for short track's motion and characteristic can have positive influences on the occurrence of non-contact injury for short track speed skaters.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.121-129
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• 2014

The purpose of this study was to investigate the effect of the toe headings on the biomechanics of knee joint in drop landing in an attempt to find the potential risk of non-contact anterior cruciate ligament (ACL) injury. Seventeen male college students ($20.5{\pm}1.1$ yrs; $175.2{\pm}6.4$ cm; $68.8{\pm}5.8$ kg), having no neuromuscular injury within an year, participated in this study. Three different toe headings such as toe-in (TI), neutral (N), and toe-out (TO) positions were tested. Motion capturing system consisting of eight high speed cameras and two force platforms were used to collect three-dimensional motion data and ground reaction force data during landing. Results indicated joint angles and peak joint moments were significantly affected by the toe headings. TI position produced larger valgus angle due to reduce knee distance in addition to higher flexion and valgus moment than other positions, which was somewhat vulnerable to the potential risk of non-contact ACL injury. TO position caused the largest internal rotation angle with smaller joint moments. Therefore, it is recommended that athletes need to land on the ground with neutral toe-heading position as possible in order to minimize the potential risk of non-contact ACL injury.

• Korean Journal of Applied Biomechanics
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• v.32 no.2
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• pp.49-55
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• 2022

Objective: This study aims to verify the front squat motions using by two different surfaces, thereby elucidating the grounds for effective training environment that can minimize the risk of injury. Method: Total of 10 healthy male crossfit athletes were recruited for this study (age: 32.30 ± 3.05 yrs., height: 173.70 ± 5.12 cm, body mass: 82.40 ± 6.31 kg, 1RM: 160 ± 13.80 kg). All participants are those who know how to do front squats well with more than five years of crossfit athlete experience. All participants have sufficient experience in front squats on two types of surface which are soft surface (SS) and hard surface (HS). In each surface, participant perform 10reps of the front squat with 80% of the pre-measured 1RM. A 3-dimensional motion analysis with 8 infrared cameras and 2 channels of EMG was performed in this study. Paired sample t-test was used for statistical verification between two surfaces. The significant level was set at α=.05. Results: The significantly decreased rectus femoris muscle activation was found in SS compared with that of HS on phase 1 (p<.05). Also, ROM of ankle joint was significantly increased in the SS compare with that of HS on phase 1 (p<.05). The muscle activity ratio of gluteus maximus/rectus femoris showed a significant difference only in SS compared with that of HS on phase 1 (p<.05). Conclusion: In conclusion, Korean crossfit boxes should consider the use of hard surface, which has a relatively less risk of injury than soft surface, in selecting flooring materials. For the Crossfit athletes, they are also considered appropriate to train on a relatively hard surface.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.217-225
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• 2009

Recently, intensive research efforts are world-widely forced on the development of sport shoes improving both the injury protection and the playing performance by taking kinesiology and biomechanics into consideration. However, the success of this goal depends definitely on the reliable evaluation of the dynamic responses of sport shoes and human foot, particularly the landing impact characteristics. It is because the landing impact force is a main source of unexpected injuries and influences the playing performance in court sport activities. This paper addresses the application of finite element method to the evaluation of landing impact characteristics of barefoot and several representative court sport shoes in running. In order to accurately reflect the coupling effect between human foot and shoes accurately, we construct a fully coupled three-diemensional foot-shoe FEM model which does not rely on the independent experimental data any more. Through the numerical simulation, we assessed the reliability of the numerical FEM model by comparing with the experimental results and investigated the landing impact characteristics, such as GRF, MIF, acceleration and frequency responses, of representative court sport shoes.

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.455-461
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• 2014

The purposes of this study were to reveal the kinematic and kinetic difference of hard ground soccer shoe, firm ground soccer shoe and soft ground soccer shoe. Soccer players were shoes of varying stud designs with some preferring the bladed studs while others opting for the conventional studded stud. Statistics were used one way-ANOVA and Tukey's Honestly Significant Difference Method. Seven healthy college soccer players were attended a test. All parameters were recorded using the Zebris system. Spatio-temporal variables were no significant difference. Lateral symmetry was statistically significant differences (p<.05). Vertical GRF parameters were no significant difference. Medial midfoot pressure, lateral midfoot pressure and central forefoot pressure were statistically significant differences (p<.05). This study demonstrates that playing surface significantly affects difference soccer shoes during soccer game. Furthermore, epidemiological investigation is warranted to determine the effects of playing surfaces on sport specific injury mechanisms.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.661-670
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• 2020

The purpose of this study was to investigate the incidence of sports injury and trend of incidence pattern of national judo athletes. The research method was analyzed based on the records of all injuries experienced by national judo athletes during training and competition for 9 years from 2008 to 2016. A total of 20,345 sports injuries requiring physical therapy were 10,768 (52.93%) for women, 9,577 (47.07%) for men, lower extremities 9,688 (47.62%), upper limbs 5,807 (28.54%), and trunk 4,850 (23.84%) and knee-related injuries (27.82%) occur more frequently than other injuries. Shoulders, feet and back were more frequent in male athletes, and ankle, neck and hand injuries were more common in female athletes. Using the binomial trend line, the trend of the decrease of sports injuries in each area was shown. However, infrequent injuries such as hands and hips tend to increase gradually. The results of this study are expected to be used as a training program for judo athletes' sports injury and basic data.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.19-30
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• 2006

The purpose of this study was to examine the effect of foot orthotics on the overall comfort and muscle activity during running. The subjects were 10 members from the joggers' club which consisted of 2 women and 8 men. These individuals ran on the treadmill by 4.0m/s speed with and without the custom foot orthotics. The data concerning the overall comfort was collected by a questionairre that examined the overall comfort, heel cushioning, forefoot cushioning, medio-lateral control, arch height, heel cup fit, shoe heel width, forefoot width, and shoe length The MegaWin ver. 2.1(Mega Electronics lid, Ma. Finland) was used to gain electromyography signals of the muscle activity; Tibialis anterior, medial gastronemius, lateral gastronemius, vastus lateralis, vastus medialis, biceps femoris, and rectus femoris were measured. The results of the study were as follows. 1. During running the overall comfort was higher for the foot arthotic condition than the nonorthotic condition. Among the inquiries the overall comfort showed the biggest difference comparing the two conditions. and the shoe heel width showed the highest score for contort. 2 The muscle activity of the biceps femoris, and vastus lateralis in the stance period decreased. due to the foot orthotics. The muscle activity of the vastus medialis in the swing period also decreased and the muscle activity tibialis anterior in the stance and swing stance decreased as well During running, orthotics showed positive result in foot comfort. The foot comfort related to decreased stress, muscle activity, and foot arch strain. Overall comfort and the adequate decrease of muscle activity were associated with injury prevention and the best method to prevent injury semms to be the maintenance of foot comfort.

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.225-233
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• 2013

The purpose of this study was to estimate the potential injury via analyzing ground reaction force components that were resulted from a prolonged-run-induced fatigue. For the present study, passive and active components of the vertical ground reaction force were determined from time and frequency domain. Shear components of GRF also were calculated from time and frequency domain. Twenty subjects with rear foot contact aged 20 to 30, no experience in injuries of the extremities, were requested to run on the instrumented tread-mill for 160 minutes at their preference running speed. GRF signals for 10 strides were collected at 5, 35, 65, 95, 125, and 155 minute during running. In conclusions, there were no significant difference in the magnitude of passive force, impact load rate, frequency of the passive and active components in vertical GRF between running times except the magnitude of active force (p<.05). The magnitude of active force was significantly decreased after 125 minute run. The magnitude of maximum peak and maximum frequency of the mediolateral GRF at heel strike and toe-off have not been changed with increasing running time. The time up to the maximum peak of the anteroposterior at heel-strike moment tend to decrease (p<.05), but the maximum peak and frequency of that at heel and toe-off moment didn't depend significantly on running time.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_1
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• pp.257-268
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• 2024

Soccer is type of sport that carries a high risk of injury. Injury is not only cause in the unlucky soccer carrier and also team performance as well as financial effects can be worse since soccer is a team-based game. The duration of recovery from a soccer injury typically relies on its type and severity. Therefore, we conduct this research in order to predict the probability of players injury type using machine learning technologies in this paper. Furthermore, we compare different machine learning models to find the best fit model. This paper utilizes various supervised classification machine learning models, including Decision Tree, Random Forest, K-Nearest Neighbors (KNN), and Naive Bayes. Moreover, based on our finding the KNN and Decision models achieved the highest accuracy rates at 70%, surpassing other models. The Random Forest model followed closely with an accuracy score of 62%. Among the evaluated models, the Naive Bayes model demonstrated the lowest accuracy at 56%. We gathered information about 54 professional soccer players who are playing in the top five European leagues based on their career history. We gathered information about 54 professional soccer players who are playing in the top five European leagues based on their career history.