The aim of this study was to acquire essential information regarding Ri Se Gwang motion(element group Ⅱ, difficulty 6.4 point, double Tsukahara with tucked 1/1 twist), which Ri Se Gwang of North Korea performed during the final vault event of artistic gymnastic at Incheon Asian Game 2014, by analyzing motional characteristics. Firstly, Ri Se Gwang technique had second jump airborne time of 1.07 seconds and airborne height of 2.91m, which have great influences on the success of technique while having horizontal and vertical velocity of 2.73 m/s and 3.87 m/s, respectively, at the takeoff. These were sufficient jump motion for successful accomplishment of the technique however flight pattern was somewhat small which was mainly oriented vertically when compared to previous studies of Yeo and YANG Hak Seon 2 techniques. Secondly, blocking angle of vault contact was small at 9 degrees while having very small takeoff angle of 79 degrees. However, it had fast average trunk rotational velocity of 545 deg./s at the vault contact phase by rapidly bending trunk from the board takeoff until approaching the vault leading to achieve fast trunk rotational velocity of 452 deg./s after the take off in order to complete the airborne rotation successfully. Thirdly, the preparation phase of Ri Se Gwang technique had a distinct characteristics that the trunk was rapidly bent during the approach to the vault attempting aggressive blocking which leads to vertically oriented flight. It showed that this characteristic assists the motion of thigh snatch and the regulation of twist which strengthen airborne rotation for airborne rotational motion. And it also showed that sufficient landing and twist angles at the landing phase are possible with free rotational motion if the height of second jump reaches 3 m.
The purpose of this study is to investigate the influence of resistance training with different exercise intensities on heart rate variability(HRV) in habitual smokers. Twenty-eight healthy young smokers participated in this study were randomly divided into three groups; CON(control), LRT(low-intensity resistance training; 50% 1RM), and HRT(high-intensity resistance training; 70%1RM), respectively. LRT and HRT groups performed an 8-week resistance training(4 upper- and lower body exercises) using weight training machines, whereas CON group maintained their regular activities. All groups were evaluated basal body composition, hemodynamic parameters, HRV as autonomic nervous function, and muscular strength (1RM and isokinetic test) before and after the 8-week training. To assess the effect of 8-week training with different intensities on autonomic regulation, time and frequency domain indices of HRV were calculated from 5min R-R interval recording. As results, both LRT and HRT groups increased baseline 1RM and isokinetic strength compared to CON group. Meanwhile, high-frequency power reflecting parasympathetic activity was significantly increased in HRT compared to CON group. In addition, normalized low frequency power(LF nu) indicating a shift of sympathovagal balance towards sympathetic predominance significantly decreased while normalized high frequency power(HF nu) which reflects vagal predominance significantly increased in HRT compared to CON group. Furthermore, improved cardiac autonomic regulation and parasympathetic activation had significant association with increased muscular strength. Overall, the 8-week training has enhanced muscular strength in both training groups, particularly autonomic balance improved in young habitual smokers with high intensity resistance training.
The purpose of this study was to examine that the reciprocal relationship between every 5km and full course running time record. In this study we extended our research scope to investigate whether any notable running time differences were existed among top level of marathoners. Comparisons were made using data which were drawn from 34 championship competitions had been held between year 2000 and year 2009 in Korea. Total 340 full time data was obtained from 340 marathoners who successfully completed their 42.195km running race, and divided into one of two categories, either upper ranked group (URG, ranked 1st~5th position in competitions they participated) or lower ranked group (LRG, ranked 6th~10th position in competitions they participated). Mean and standard deviation were calculated from SPSS (VER. 20.0), and repeated measures of ANOVA and Pearson's correlation was adopted to perform statistical analyses. There was no statistical difference of the running record during first 5km, however running time form all other 5km running sections was significantly faster in URG than LRG (p<.001). The gap of running time record between URG and LRG was getting more and more significant after 20km running. The quickest running record was found during 2nd 5km section (i.e., 5~10 km) and the each section's race time was getting drastically slower during 6th~7th 5km section running regardless of the study groups. Drawn conclusions from this study were that athletes use the strategy of deciding victory in both the beginning and the latter phase of marathon running. This implies that athletes who have the capacity, which make them run faster than others during the very beginning of marathon competition, and/or during 25~35km running sections would be the most preferable for the victory at the finish line.
The objective of this study was to investigate the effects of 12-weeks of vitamin D supplementation and circuit training on skeletal muscle mass in elderly women with type 2 diabetes mellitus and vitamin D deficiency. Forty eight elderly women with type-2 diabetes mellitus and vitamin D deficiency were randomly assigned to control(n=10), vitamin D supplement(n=11), exercise(n=12), and vitamin D supplement+exercise(n=15) groups. Dependent variables were measured before and after the 12-week interventions. Major outcomes included body composition, fasting glucose, insulin, and 25(OH)D concentration. ASM(apeendicular skeletal muscle mass), SMI(skeletal muscle mass), and HOMA-IR (homeostasis model for insulin resistance) were calculated. Women assigned to the vitamin D supplement consumed 1,200 IU of vitamin D orally per week for 12 weeks. Women assigned to the exercise intervention performed a circuit training at an intensity of 60%~80% of HRmax with a frequency of 3 days per week for 12 weeks. Compared to control group, all groups had significant loss of body weight and increases in serum 25(OH)D after the 12-week intervention. ASM and SMI increased significantly in only vitamin D+exercise group. Regardless of treatments, no significant group differences were found in changed scores of fasting glucose, insulin, and HOMA-IR. In conclusion, vitamin D + exercise would improve the loss of ASM and SMI compared with vitamin D or exercise alone.
PURPOSE This study compares the effects of video group and metaverse group counseling for student athletes to analyze differences in immersion, sychological skills learning effects, and each approach’s participation experiences. METHODS Twenty-four high school archery students were divided into three groups: a metaverse experimental, a video comparison, and a control group. For the experimental and comparative groups, 10 non-face-to-face psychological skills training sessions were conducted. With the control group, results were compared and analyzed by measuring psychological skills and social presence pre- and post-training. Additionally, analysis of the qualitative effects of psychological skills training was performed. RESULTS The psychological skill test’s quantitative analysis of the video comparison group showed a more significant effect in anxiety control factors than the metaverse experimental and the control groups. Moreover, in the social presence test, both the metaverse and the video groups showed significant differences in social presence and satisfaction; furthermore, Scheff post-verification results showed that the two environments’ satisfaction was significantly higher than that of the control group. Qualitative analysis confirmed that the metaverse and video groups experienced psychological, technical, and relational changes in common. CONCLUSIONS Although the metaverse group using avatars was likely to increase immersion, both the video and the metaverse groups were effective in psychological skills training, suggesting that the training effect may vary depending on the non- face-to-face environment’s stability and participation method. Future studies should examine effects of applying the metaverse platform to sports psychological skills training and various psychological support activities by solving the metaverse environment’s technical limitations.
PURPOSE This study aimed to investigate how a 10-week online live Pilates training held during the COVID-19 pandemic affected body composition, cardiovascular function, and physical fitness in sedentary middle-aged obese women. METHODS Thirty obese women, aged 30 to 49 years (BMI : 25kg/m2 or more; waist circumference: 85cm or more) who were leading a sedentary lifestyle for more than 8 hours a day were assigned to one of two groups—that is, the Pilates training group (TR) and the control group (CON). Four participants were dropped from the study during the intervention period. Participants in the TR group (n=13) performed online live mat Pilates exercises (3 sessions per week; 60 minutes per session for 10 weeks, whereas participants in the CON group (n=13) were asked to maintain their normal lifestyles during the same intervention period. Independent variables related to body composition, cardiovascular function, venous function in the lower body, physical fitness, and 1-RM (repetition maximum) were measured at pre-test and post-test, and data were compared between the two groups and between the two tests. RESULTS 1) Regarding body composition, body weight, body mass index, fat mass, and waist circumference decreased significantly in the TR group. 2) Regarding cardiovascular function, stroke volume and cardiac output increased significantly in the TR group, and total peripheral resistance decreased significantly in the TR group. 3) Regarding venous function in the lower body, blood flow velocity and blood flow volume of the parenchyma area increased significantly in the TR group. 4) Regarding physical fitness, cardiorespiratory endurance, muscular endurance, flexibility, and balance improved significantly in the TR group. 5) 1RM of biceps curl, lat pull-down, leg curl, and leg extension increased significantly in the TR group. CONCLUSIONS It was concluded that the 10-week online live Pilates training had positive effects on the body composition, cardiovascular function, venous function in the lower body, and physical fitness of middle-aged obese women leading sedentary lifestyles.
PURPOSE Blood pressure (BP) in hypertensive individuals is reduced by the accumulation of post-exercise hypotension (PEH) induced by a long period of training. This study aimed to investigate the effects of intensity of two different aerobic exercises with identical energy expenditure on post-exercise blood pressure and cardiovascular function in prehypertensive men. METHODS Eleven prehypertensive men in their 30s participated in two trials repeatedly. In the first trial, the exercise was moderate in intensity and continuous (MICE) with 70% of VO2max, and the exercise in the second trial was high-intensity interval exercise (HIIE) with 50% and 90% of VO2max. Each exercise was performed for 30 min, and the variables related to BP and cardiovascular function were measured at certain times for 1 hr during the recovery phase. RESULTS Our main findings are as follows: (1) Systolic blood pressure was significantly lower at 30 and 45 min of recovery time than the baseline in the HIIE trial, and systolic blood pressure was significantly lower in the HIIE trial than the MICE trial at 10, 15, and 30 min of recovery time. (2) The rate pressure product was significantly higher in the HIIE trial than the MICE trial at 15, 30, 45, and 60 min of recovery time. (3) The heart rate was significantly higher in the HIIE trial than the MICE trial at 15, 30, 45, and 60 min of recovery time. (4) Stroke volume was significantly lower in the HIIE trial than the MICE trial at 30 min of recovery time. (5) Cardiac output was significantly higher in the HIIE trial than the MICE trial at 15 min of recovery phase. (6) Total vascular conductance was significantly higher in the HIIE trial than the MICE trial at 15 and 30 min of recovery phase. (7) Total peripheral resistance was significantly lower in the HIIE trial than the MICE trial at 15 and 30 min of recovery phase. CONCLUSIONS The HIIE shows a higher cardiovascular stress than MICE; however, HIIE contributes to the augmentation of PEH and improvement of cardiovascular function. Therefore, HIIE rather than MICE should be suggested in BP control and enhancement of cardiovascular function in prehypertensive males.
Purpose The purpose of this study is to measure the daily physical activity of male and female middle school students according to the period (VD: vaction day, SNPE: school day no PE, SPE: school day with PE) by using 3-axis accelerometer, and to compare the characteristics of adolescent physical activity according to gender and period. Methods The subjects were 130 middle school students (68 male, 62 female students). Data collection was performed using a 3-axis accelerometer(GT3X model, ActiGraph). Collected data were converted into time by intensity and rate using physical activity analysis program (Actilife v6.11.9) and analyzed by statistical program (SPSS 25.0). One-way ANOVA and independent sample t-test were used for statistical analysis. Tukey's HSD was used as a post analysis. The statistical significance level was .05. Results As a result, during each periods(VD, SNPE, and SPE), except for MVPA(moderate to vigorous physical activity) time on SPE, sedentary and MVPA time were significantly higher in female students, and low intensity and total physical activity time were significantly higher in male students. For male students, total physical activity time was higher in the order of SPE, SNPE, and VD, and for female students, physical activity time during the semester(SNPE and SPE) was significantly higher than VD. For male students, MVPA time was significantly high in order of SPE, SNPE, and VD, and for female students, it was high in order of SPE, SNPE, and VD but only significant difference occurred between SPE and VD. For both male and female students, sedentary time was high in the order of VD, SNPE, and SPE, but the sedentary time during vacation was significantly higher than during the semester. Conclusions When summarizing the results, first, it was confirmed that school and physical education classes as a physical activity space play a significant role in physical activity, especially MVPA, of male and female middle school students, second, the physical activity effect of physical education class was found to be more effective in male students. Based on the results of this study, it is necessary to conduct studies on various grades and to explore various factors affecting physical activity in a complex way.
Purpose The purpose of this study was to evaluate the moderate to vigorous physical activity(MVPA) and sedentary time measured by accelerometer. Furthermore, the level of physical activity and adherence rate of physical activity guideline(PAG) were compared with the self-reported questionnaire. Methods The MVPA, sedentary time, and adherence rate of PAG according to age and sex were examined to people who agreed to wear accelerometers among the participants of the 2014-2015 Korea National Health and Nutrition Examination Survey. To compare the relationship between accelerometer and self-reported questionnaire, Chi-squared test and Spearman correlation analysis were performed. Results The MVPA of the accelerometer-total(AT) was 40.6 minutes/day for men and 31.1 minutes/day for women. Sedentary time was 502.9 minutes/day for men and 498.9 minutes/day for women. The MVPA of accelerometer-bout(AB) estimates was 16.4 minutes/day for men and 14.2 minutes for women. On the other hand, the MVPA of the self-report was 95.8 minutes for men and 64.3 minutes for women, and the sedentary time was 471.2 minutes for men and 455.2 minutes for women. The adherence rate of PAG was 55.6% of the self-report, 56.1% of the AT, and 21.4% of the AB. The correlation between self-report and accelerometer was statistically significant(p < 0.01), but showed a weak correlation coefficient(rho=0.112-0.351). There was no association between AB and self-report(p < 0.01). The sensitivity and specificity of the self-report were 71.3% and 48.6%, respectively. The positive and negative predictive values of the self-report were 27.5% and 86.1%, respectively. Conclusions As a result of this study, self-reported physical activity level by questionnaire had more MVPA and less sedentary time than the accelerometer-determined physical activity. In addition, the adherence rate of the PAG differed from accelerometer and self-report. The difference was significantly increased when comparing AB with the self-report. Therefore, great care must be taken when interpreting accelerometer and self-report questionnaire. Further research will be needed on specific methods that can be used by complementing the two measurement tools.
Purpose The purpose of the study was to determine difference of body composition, bone mineral density and health-related fitness by physical activity level in young women. Methods A total of 90 women aged 19-29 years participated in this study. The subjects were divided into three groups (low, middle, and high level) according to the physical activity level estimated by bone-specific physical activity questionnaire(BPAQ). Body height and weight were measured. Body composition parameters including four sites of bone mineral density(BMD) were estimated by DXA (Hologic, QDR-4500, USA). Health-related fitness tests was assessed using sit & reach, grip strength, sit-ups, and VO2max. Statistical analysis was performed using SAS version 9.4. All data were presented in terms of means and standard deviations. One-way ANOVA was applied to determine difference of dependent variables by physical activity level. Duncan's multiple range test was used as a post-hoc test. The statistical significance level was set at p < .05. Results There were significant differences on body weight(F = 4.867, p = .01), body mass index(F = 5.053, p = .008) and fat-free mass(F = 8.364, p = .0001) among the three groups. Significant differences were found on whole body BMD(F = 16.730, p = .0001), lumbar BMD(F = 11.480, p = .0001), femur BMD(F = 42.182, p = .0001) and forearm BMD(F = 5.560, p = .005) among the three groups. There were also significant differences on sit and reach(F = 11.433, p = .0001), sit-ups(F = 17.972, p = .0001), VO2max(F = 3.106, p = .05) and duration of GXT(F = 7.479, p = .001). Conclusions There were differences on body composition, bone mineral density and health-related physical fitness by physical activity levels. Nevertheless, the questionnaire used in this study was not able to judge participation in various exercise types including aerobic exercise or resistance exercise. Therefore, in the future study, longitudinal study considering various types of physical activity and dietary intake will be needed.
