Earticle

[PURPOSE] The purpose of this study was to compare on maximum vertical ground reaction force(MVGRF), accumulate iEMG, average iEMG, and MPF depend on preliminary 3 type jump, and to analyze the correlation among vertical ground reaction force and muscle activities, and to provide information for effective vertical jump. [METHODS] The subjects were consisted of 9 college men without knee pain or medical history. The preliminary jump was consisted 40cm drop jump, Sargent jump and double jump. The arm was crossed in front of chest to avoid the effects of upper arm. The maximum vertical ground reaction force, and accumulate iEMG, average iEMG, and MPF on right side 5 muscles during preliminary 3 type jump were measured. [RESULTS] The MVGRF was significantly different among preliminary 3 type jump(p<.01), followed by drop jump, double jump, and Sargent jump. In cumulative iEMG, there was a significant difference on tibialis anterior and gastrocnemius muscles, and cumulative iEMG of vastus lateralis, biceps femoris, and gastrocnemius were in the order of drop jump, double jump, and Sargent jump similar with MVGRF. In average iEMG, there was a significant difference in biceps femoris, and gastrocnemius (p<.05, p<.01), and average iEMG of vastus lateralis, and gastrocnemius were similar with MVGRF. In MPF, there were significant differences in biceps femoris, and gastrocnemius (p<.05). In all of the five muscles, the order of the Sargent jump, double jump, and drop jump was different from MVGRF. [CONCLUSIONS] There was no significant correlation between the MVGRF, cumulative iEMG and average iEMG of the five muscles according to preliminary 3 type jump. According to preliminary jump type, the number of positive correlated muscles varied from 5 to 0, and the muscles with the highest correlation were also different.

[PURPOSE] The purpose of this study was to identify the effects of TaeKwonDo(TKD) training with additional lower limb strengthening exercises on quadriceps muscle strength and Y-Balance in female university students. [METHODS] 30 healthy female university students participated in two trials: (1) TKD training and lower limb strengthening training and (2) a control group. Experimental group was composed of 15 students training for ten weeks, two hours a days, two days a week. Upon completing, students were measured on quadriceps muscle strength, static and dynamic balance. The data were analyzed utilizing two-way repeated ANOVA. [RESULTS] The results showed that there were no significant differences in weight, body fat, and BMI between groups. The result showed a significant interaction in left knee muscular power between groups(p<.05), and the training group showed a significant improvement(p<.05). The result showed a significant interaction in the static balance(p<.05) and the Y-balance(p<.001), the results showed a significant differences between groups in the static balance(p<.05) and the Y-balance(p<.001). [CONCLUSIONS] TaeKwonDo and lower limb strengthening training gives positive effects on left quadriceps muscle strength and improves the overall of balance of female university students. The combined training program can be an effective way to enhance balance and can be used for patients who have balance problems in their lower bodies.

[PURPOSE] This study was to investigate comparison analysis of isokinetic strength, physical fitness profiles between male adolescents; greco-roman and free style wrestlers. [METHODS] The subjects were twenty-one middle and high school wrestlers players. Subjects were classified into two group; greco-roman style group(n=9) and free style group(n=12). All subjects were tested for height(cm), weight(kg), body mass index(BMI, kg/m2), and isokinetic function, and physical fitness factors. [RESULTS] As results, peak tourque, %BW, Hamstring/Quadriceps ratio(HQR) were not significantly different between the greco-roman and free style group. The relative grip strength showed a higher tendency in the free style group than in the greco-roman style group(p=.068). The sergeant jump was observed a significantly high in the free style group than in the greco-roman style group(p=.048). The absolute back strength was observed a significantly high in the in the greco-roman style group than free style group(p=.043). [CONCLUSIONS] This study demonstrated that the physical factors were different between wrestling style. A more detailed study of greco-roman and free style in adolescent and adult wrestlers are required to improve performances in the future.

[PURPOSE] Isokinetic strength test is the measurement of force-velocity or torque angle. Isokinetic strength of the knee extensor and flexor muscle is often assessed using an isokinetic dynamometor such as Cybex system. Question remains concerning the reliability of the isokinetic muscle strength measurements. The purpose of this study was to establish the minimum number of trial required to assess reliable estimates of isokinetic strength measurement using Cybex system(Cybex 770). [METHODS] A total of 70 adults (mean age 19.38 ± 3.32 years; 35 male and female each) completed the isokinetic strength tests using Cybex system. Concentric muscle strengths were measured at 60 degrees per second over 4 repetitions. Following data screening, participant’s data were finally analyzed by muscle strength measurements (knee extensor and flexor muscles) and gender using the Genealizability theory. A single-facet crossed design [i.e., participant(P) × trial(T)] was used. G-study was performed to quantify the percentage of variance associated with each facet and interaction in the model. Follow-up D-study was performed to determine the optimal combinations of number of repetition trial to achieve a desirable reliability coefficient (G≥.80). [RESULTS] The knee extensor muscle of male and female were 158.48 ± 33.89Nm and 96.78 ± 23.60Nm respectively. The knee flexor muscle of male and female were 83.52 ± 31.92Nm and 45.97 ± 11.94Nm, respectively. For the knee extensor muscle, the results from G-study show that P accounted for 71% and 90% variance for male and female. T had no effect on the total variance. The number of trials to achieve G≥.80 for male and female were 2 and 1, respectively. For the knee muscle G-study results show that P accounted for 94% and 77% variance for male and female. T had little effect on the total variance (< 1%). The number of trials to achieve G≥.80 for male and female were 1 and 2, respectively. [CONCLUSIONS] The number of examination for reliable values is at least 2 times in isokinetic knee strength test.

[PURPOSE] The purposes of the present study were to explore level of physical activity in adolescents, to identify the differences in psychological and social variables by stage of physical activity, and investigate the relationship of psychosocial variables with physical activity. [METHODS] A total of 561 adolescents (male: 229, female: 332, mage = 13.32years) in the Nowon district were voluntarily participated in the study. Stage of physical activity measure, self-efficacy measure, exercise attitude scale, social support measure, and self-regulation scale for physical activity were applied to evaluate the participant's level of physical activity, psychosocial variables relating to physical activity. Frequency analysis, X 2 -square test, MANOVA, and regression analysis were conducted to analyze data obtained in the study. [RESULTS] 70.5% of participants reported that they are inactive (precontempolation and contemplation) or doing physical activity on an irregular basis. Moreover, self-efficacy, exercise attitude, internal motivation, and parental support were significantly different according to stage of physical activity. These psychosocial variables had 62% of variance in explaining physical activity and of them self-efficacy was best predictor to account for physical activity. [CONCLUSION] The present study suggests that further study should apply structure equation model to test causal relationship between the psychosocial variables and physical activity.

[PURPOSE] The purpose of this study was to identify the motivators of physical activities by applying the planned behavior theory to adults as the subjects. [METHODS] Four hundreds fifty adults in sports and cultural facilities in S district in Seoul participated in the research. Also, attitude, subjective norm, behavioral control perception, behavioral intention, physical environment and physical activity questionnaire were used as measurement tools. [RESULTS] Descriptive statistics, correlation analysis and path analysis were utilized. The results are as follows. Attitude, subjective norm, behavioral control perception and physical environment were shown to have a significant influence on behavioral intention. Whereas intention and behavioral control perception had a direct effect on physical activities, physical environment did not affect physical activities. However, through the extension model, it was confirmed that physical environment influences behavioral intention. [CONCLUSIONS] These results suggest that integrated research related to socio-environmental variables that may affect physical activity is needed. This study can contribute to the development of the psychological theory through multidimensional interpretation.

[PURPOSE] The purpose of this study was to investigate the correlation analysis of the variables between lower body stiffness(knee joint stiffness & leg spring stiffness) calculated by three-dimensional motion analysis system and the landing error score calculated using the landing error score system during drop vertical jump. [METHODS] Ten professional female soccer players participated in the study. Pearson's coefficient of correlation was used to determine the correlation between the landing error score and the lower body stiffness(knee joint stiffness & leg spring stiffness) during drop vertical jump on the 30cm box. [RESULTS] There was a negative correlation between the landing error score and the knee joint stiffness(r=-0.412, p<.05), and there was a high negative correlation between landing error score and leg spring stiffness(r=-0.614, p<.05). [CONCLUSIONS] The landing error score, which can be easily used in the sports field, showed a significant negative correlation with lower body stiffness, which is a risk factor of anterior cruciate ligament injury.

[PURPOSE] The purpose of this study was to provide basic data for prevention of injuries by understanding the sports injury status of middle and high school fencers. [METHODS] The subjects were 399 middle and high school fencers. Survey was classified as injury rate, injured site, tissue and plans of injury prevention during training. The collected data were analyzed by frequency analysis, x 2 tests and two-way ANOVA using the spss program to identify differences in gender, grade, and type. [RESULTS] The results of this study were as follows: First, female fencers (p <.011) and high school fencers (p <.000) experienced statistically significant injury than male and middle school fencers. The incidence of injury per training hour was significantly higher female fencers than male fencers (p <.035) in middle school. Second, the injury of ankle was the highest rate in total groups (18.22%), and the injured tissues were muscles (27.46%) and ligaments (27.27%) were the highest injury rate in total groups. Third, plans of injury prevention showed that the warm up and cool down were the highest rate (38.96%) in all total groups. [CONCLUSIONS] These results suggest that development of specific warm-up and cool-down program and ankle strengthening exercise should be studied to prevent injuries for middle and high school fencers, particularly female fencers should be more careful in preventing injuries.

[PURPOSE] The purpose of this study was to investigate the changes of Learned Resourcefulness and self - management behaviors of the athletes in the rehabilitation process after sports injury and to investigate how the rehabilitation success rate changes according to the level of Learned Resourcefulness and self - management behavior. [METHODS] In the preliminary study, Learned Resourcefulness, sports psychology, and self - management scale of 150 university student players were verified using SPSS program 18.0. In this study, we selected four athletes in the process of rehabilitation after a sports injury of 4 weeks or more from a rehabilitation medicine specialist, and analyzed the cases by measuring initial, middle and late rehabilitation of each. [RESULTS] First, it was confirmed that athletes with high Learned Resourcefulness improved sports psychology skills during the rehabilitation process. Second, It was confirmed that athletes with high Learned Resourcefulness improved somewhat in self-management behavior during the rehabilitation process. Third, it was confirmed that athletes with a high self-management score improved somewhat in sports psychology skills during the rehabilitation process. Fourth, it was confirmed that Learned Resourcefulness were improved during the rehabilitation process of players with high self-management score and low players. Fifth, in the self - management, the change of the perceived rehabilitation success rate of a player with a high score and a player with a low score increased partly. Sixth, athletes with high Learned Resourcefulness have found that the rehabilitation success rate perceived during the middle to the late rehabilitation process sharply rises. [CONCLUSIONS] The results showed that the rehabilitation success rate was affected by the level of Learned Resourcefulness and self - management behaviors among the players who were in rehabilitation process after sports injury.

[PURPOSE] The purpose of this study was to analyze the relationship between serum dehydroepiandrosterone (DHEA) concentration and physical fitness after exercise in middle-aged women. [METHODS] Subjects were randomly assigned to yoga and elastic band resistance exercise group (55.21±3.78 yrs, n=11) and non-exercise group (54.10±2.51 yrs, n=7). The exercise group participants performed upper and lower extremity exercise three times per week for 12 weeks. Body weight, height, %fat, serum DHEA concentration, sit-up, grip strength, and one leg stand (with close eyes) were measured on subjects. [RESULTS] Serum DHEA concentration showed an increased trend after exercise training as compared to before exercise training, but no significant difference between before and after exercise training. Also, variables related to physical fitness as sit-up, grip strength, and one leg stand were significantly (p<.05) increased after exercise training as compared to before exercise training. However, serum DHEA concentration and variables related to physical fitness showed no significant relationship. [CONCLUSIONS] Yoga and elastic band resistance exercise training could improve muscular physical fitness, and could be a potential method increasing serum DHEA concentration in middle-aged women, but this possibility is an obscure. In future studies, the intensity of exercise for increasing physical fitness of middle-aged women and the exercise intensity for metabolic function enhancement due to elevated DHEA concentration in blood should be presented differently.