Muscle Activities of the Brachioradialis and Extensor Carpi Radialis Longus According to the Type of Backhand Stroke in Badminton / 대한스포츠의학회지

PURPOSE: The purpose of this study was to investigate the muscle activities of the brachioradialis and extensor carpi radialis longus according to the type of backhand stroke in badminton.METHODS: To measure the muscle activities, we used electromyography (EMG) equipment to measure EMG values by performing maximal voluntary contraction (MVC) of the forearm muscles, which depends on the type of backhand stroke. With these values, the %maximum voluntary isometric contraction values were obtained. The data were calculated using SPSS ver. 21.0 and one-way repeated measures analysis of variance with a post-hoc least significant difference test.RESULTS: In this study, the backhand clear achieved higher maximum muscle activity values than those by the backhand push, under clear, and drive in the brachioradialis. The backhand smash achieved higher maximum muscle activity values than those by the backhand push in the extensor carpi radialis longus.CONCLUSION: The backhand clear is associated with a higher injury rate than those associated with the backhand push, under clear, and drive. The backhand smash is associated with a higher rate of the occurrence of tennis elbow than that associated with the backhand push. To prevent injuries, it is considered that the forearm's strength, stretching before and after exercise, and sufficient time to rest are important.

Prevalence of Anterior and Posterior Cruciate Ligament Operation in the Knee Joint According to Sex Difference / 대한스포츠의학회지

Purpose@#The purpose of this study was to investigate the prevalence of knee anterior and posterior cruciate ligament operation performed in Korea from 2015 to 2018. @*Methods@#The participants of the study were 62,213 patients with knee anterior and posterior cruciate ligament operation provided by the big data from the Korea Health Insurance Review and Assessment Service from 2015 to 2018. Using the Korean standardized population of the National Statistical Office, the prevalence rate per 100,000 persons was analyzed by dividing them into sex and age. @*Results@#As a result, the prevalence of knee anterior and posterior cruciate ligament operation by age from 2015 to 2018 was high between 20 and 29 years for men, while that for women was high between 10 and 19 years. @*Conclusion@#The prevalence rate per 100,000 persons of knee ligament was higher in the 20s for men, while in the 10s for women.

The Effects of Foot Position on Dynamic Stability during Squat in Female with Genu Varum / 대한스포츠의학회지

PURPOSE: The aim of this study was to investigate the effects of foot position on dynamic stability in female with genu varum. METHODS: Eight females with genu varum participated in this study and performed the four squat exercise methods that foot position (−45°, 0°, +45°) and 0° squat with band. Center of pressure (COP; anterior-posterior, medial-lateral, traveled distance, ellipse area) and ground reaction force as dynamic stability were measured using footscan system. Multivariate analysis of variance and one-way repeated analysis of variance measurement with Tukey honestly significant difference were used to identify significant differences of foot angle (−45°, 0°, +45°) and 0° squat with band method. RESULTS: In anterior-posterior COP displacement, −45° foot angle and 0° squat with band were significantly showed lower than +45° foot angle squat (p=0.006). Also, in COP traveled distance, 0° squat was significantly showed lower than +45° foot angle (p=0.019). During the descending phase, ground reaction force significantly showed in −45 foot angle was lower than other exercise methods. CONCLUSION: The 0° squat with band exercise showed higher dynamic stability and +45° foot angle squat exercise showed lower dynamic stability in female with genu varum.

Analysis of Landing Error Scoring System during Drop Vertical Jump on Anterior Cruciate Ligament Injury Risk Factors in Elite Fencers / 대한스포츠의학회지

PURPOSE: The aim of this study was to identify the differences of gender and detail items by using landing error scores during drop vertical jumping that can be used in the field for elite fencers and to use them as basic data for prevention of injury. METHODS: The subjects were 42 elite fencers. Independent sample t-test was used to compare the landing error scoring system (LESS) score between the groups. In order to compensate for errors that may occur in multiple comparisons, they are corrected through the Bonferroni collection. The significant differences between the groups were evaluated using Cohen effect difference, and one-way analysis of variance was performed for differences in epee, fleuret, and sabre. RESULTS: The comparison of landing error scores between male and female fencer groups showed that the knee valgus angle at initial contact, lateral trunk flexion angle at initial contact, stance width-narrow, foot position-toe out, symmetric initial foot contact, in the total score of LESS items, female fencer group was higher and statistically significant difference was found. CONCLUSION: In the case of fencing players, there is no significant difference in the LESS scores according to the items. However, when comparing gender, female fencers have higher LESS scores than male fencers; female fencers should be more careful in preventing injuries.

Analysis of Landing Error Scoring System during Drop Vertical Jump on Anterior Cruciate Ligament Injury Risk Factors in Female Ballet Dancers and Female Soccer Players / 대한스포츠의학회지

The incidence of anterior cruciate ligament (ACL) injuries among female ballet dancers is much lower than among female soccer players, there is currently little research examining the landing error scoring system (LESS) of female ballet dancers and female soccer players. The purpose of this study was to investigate the LESS during drop vertical jump on ACL injury risk factors in female ballet dancers and female soccer players. Thirteen professional female ballet dancers and elite female soccer players participated in the study. Independent sample t-test was used to compare the LESS score between the groups with Bonferroni collection. The elite female soccer player group showed significantly higher stance width-wide, foot position-toe out, symmetric initial foot contact, overall impression and total LESS score than those of the professional ballet dancers.