The purpose of this study is to establish the efficient defensive strategy from analyzing the goalkeeper’s gaze behavior and defensive motion in both field hokey penalty corner and penalty stroke. To achieve this goal, 3 national team goalkeepers’ gaze behavior and defensive motions were analyzed, as well as the player’s visual strategies from their interview contents. For the apparatus, multi-channel integrational system were used for analyzing goalkeeper’s reaction movement and personal visual strategies. The result is as follow: First of all, In the penalty stroke, goalkeepers were tended to focus on the bottom of the shooter’s hokey stick. Second, national hokey players had quicker anticipating saccadic movement. For this reason, their visual fixation locations were arrived in targets earlier than the hockey ball. Lastly, in the interview contents, they were reported to focus just on the ball from not disturbed by other various objects(body, hockey stick). However, they actually observed various body parts of shooters. These results imply that we need to develop an effective perceptual skill training in order to anticipate the shooting performance more accurately and rapidly. These types of perceptual and cognitive skill training should be conducted with information on knowing their specific visual cues in anticipating shooting direction.
The purpose of this study was to confirm the differences between winner and loser groups of national team participated in the World Taekwondo Championships statistically and trends of psychological status according to applying mental coaching. In order to achieve the purpose it was the selection of 16 national members participated in the 2013 World Taekwondo Championships in Puebla. Data was selected by TOPS(test of performance strategy). The survey was conducted before and after applying the mental coaching and the game soon after. Data processing results were calculated utilizing Excel and SPSS 21.0 version. Based on the findings issue the conclusions were as follows. First, the psychological state of the winner and loser groups showed a different trend in the self-talk, emotion control, performed automatically, imagery, struggle, negative thinking, relaxation, condition factor. Winner group was shown maintenance or better trends of psychological state in the three times measurements on the other hand, loser group was shown decrease in the game soon after. Secondly, winner and loser groups are statistically significant differences in the psychological state of competition in self-talk, struggle, negative thinking, solving tension factors. In other words, The winner group had higher score in the four factors than loser group in the competition.
This study was to identify the structure of anger behavior that athletes illustrated in competitions. In order to achieve research purpose, 167 high school, college, and professional athletes responded to open questionnaires. Targeting 541 players, the structural validity of psychological measurement was verified. As a result of analyzing the sources of anger behaviors during matches, four factors of anger-out, anger-in, anger control, and anger-helplessness were deduced. Afterwards, the validity of 4 factor-model was verified through correlation analysis with trait anger and verification of group differences. That is, the level of trait anger had a positive relationship with expression of anger-out and anger-helplessness while it had a negative relationship with anger-in and anger-control. Especially, the behavioral aspect such as anger-helplessness is a structure that has not been found in other criteria of anger behavior and it reflects the uniqueness of sports situation. Based on such results, the significance of sport anger behavior and implications were discussed.
Vertical jumping is one of basic skills in many sports activities. Maximizing vertical jumping performance requires large “power”, which implies that one should generate force against the ground in a short period of time. In order to gain better understandings of how human musculo-skeletal system mechanically functions to achieve maximal power in vertical jumping, the proposed “dynamic catch” mechanism, one of “power amplification” mechanisms through the role of muscle-tendon interaction, was specifically reviewed base on the morphological and mechanical characteristics of lower limb muscle-tendon complex. By understanding basic structural and functional features of human muscle-tendon interaction, this review aims to provide basic scientific information for training and rehabilitation and promote convergence researches in related areas, such as sports biomechanics, mechanical engineering, and sports medicine.
This study was aimed at investigating the effect of head-tilt angle on autonomic nerve modulation immediately after a single bout of exercise in twenty-three healthy young males(age 21.96 ± .4 yrs). Post-exercise HRV was measured on supine(SUP), -15°head-down tilt(HDT), and +15°head-up tilt(HUT) followed by 20 min aerobic exercise with moderate intensity(40% of VO2max). As results, heart rate recovery during post-exercise on each tilt angle(SUP vs. HDT vs. HUT) had no significant difference(p> .05). Also, there were no significant difference in time and nonlinear domain index of HRV. On spectral analysis; however, frequency domain index(HF, LF/HF ratio, HF/TP ratio, HF nu, LF nu) had significant difference(p< .05) on each tilt angle at recovery. Especially, PNS reactivation index (HF, HF/TP ratio, HF nu) had significant increase on HDT compared to HUT(p<. 05) while SNS activation index (LF/HF ratio, LF nu) had significant decrease on HDT compared to HUT(p<. 05). Furthermore, there were significant interaction between recovery time elapsed and each tilt angle (except for HF/TP ratio). In conclusion, -15°head-down tilt promotes the effective cardiac vagus nerve reactivation immediately after a single bout of aerobic exercise.
It has well known that post-exercise hypotension (PEH) after a bout of aerobic exercise was a major mechanism to reduce blood pressure though exercise training, and that citrulline supplementation reduced blood pressure by increasing nitric oxide in vivo. However, the effects of citrulline supplementation on PEH have not been fully elucidated yet. This study was designed to examine the effects of citrulline supplementation on PEH after a bout of aerobic exercise in prehypertensive and normotensive 20s males. The effects of a four-day citrulline or placebo treatment on blood pressure, cardiovascular function, and blood lactate concentration measured at rest and during recovery phase after a bout of exercise performed for 30 min at 70% VO2max were compared and analyzed. All subjects participated in a citrulline trial and a placebo trial repeatedly according to a counter-balanced order. Main results of the present study were as follows: 1) Systolic blood pressure, diastolic blood pressure, and mean arterial pressure measured at 10-60 min of recovery phase in citrulline trial were significantly lower than placebo trial. Rate-pressure product measured at 30 min and 45 min of the recovery phase in citrulline trial was significantly lower than placebo trial. 2) No significant differences were found in heart rate (HR), cardiac output (CO), and total peripheral resistance (TPR) measured during the recovery phase between two trials. There were significant differences in HR, stroke volume, CO, and TPR among times within a trial. 3) No significant difference was found in blood lactate concentration measured at rest and during the recovery phase between two trials. The results would be summarized that the PEH was augmented by the citrulline supplementation, and that burden to cardiac muscle as well as cardiovascular function were not affected by the citrulline supplementation. It was concluded that the short-term citrulline supplementation would be very effective to augment the PEH. A research investigating the effects of citrulline supplementation on the PEH in pre-hypertensive and/or hypertensive individuals would be warranted. In addition, a study examining the effects of citrulline supplementation during long-term exercise training on the blood pressure in hypertensive patients also would be warranted in near future.
The purpose of this study was to investigate the effect of wearing of safeguard devices on various blood ions (i.e., Na+, K+, Ca2+) concentrations, gas parameters (PO2, PCO2, hematocrit [Hct], hemoglobin [Hb], Saturated [Sat] O2), and energy substrates (i.e., glucose, free fatty acid [FFA], lactate) concentrations during Kumdo training. Research scope extended to examine the heart rate changes during each exercise sessions. In order to achieve the research goal, 10 male elite Kumdo players, who play for G city in Gyeongsangbuk-do, were participated, and their mean maximum oxygen uptake level was 51.2(±6.1)mL· kg-1min-1. All subjects undertook Kumdo training sessions twice, which carefully pre-planned and consisted of routinely carrying out exercise program. Training period for each session was 80 min long including 10 min each for warm-up and warm-down period, but the conditions with wearing body protection devices were different following either with wearing complete set of safeguard devices or without wearing any safeguard devices except general training cloth. Heart rate was measured by every minute interval. K+ and Ca2+ showed interaction effect between the conditions with wearing safeguard devices and conditions with time of Kumdo training. Hct and Hb level significantly increased after 60 min Kumdo exercise regardless of wearing safeguard devices. Kumdo training induced dropping of blood pH independently with wearing safeguard device conditions, however the values and/or concentrations of PO2, Na+, glucose, lactate, Sat O2were significantly increased. Heart rate was maintained marginally higher values throughout exercise period when safeguard devices were worn. Based on these results, it was concluded that wearing the safeguard devices could possibly be causing a physiological metabolic changes, and this may be drawn by increased body fluid loss and energy expenditure. Further study should be undertaken to examine the effects of wearing safeguard devices on hitting intensity and hormone secretion and concentrations, that closely associated with body fluid and ion balance during Kumdo exercise and/or training.
The purpose of this study was to investigate the effects of 8 weeks of aerobic training and resveratrol supplementation on a body composition, physical fitness, insulin resistance, liver function, blood pressure, and heart rate. Fifty-one elderly women were randomly assigned to aerobic training group (EX: n=12), resveratrol supplementation group (R: n=13), combined aerobic training and resveratrol supplementation group (EX+R: n=12), and control group (CON: n=14). The subjects in EX group exercised three sessions per week, 40 minutes per session for 8 weeks, the subjects in R group took 500 mg of resveratrol per day for 8 weeks, and the subjects in EX+R group received both treatments. The subjects in CON group were asked to maintain normal daily life pattern without any treatment for the same period of intervention. Body composition, physical fitness, insulin resistance, liver function, blood pressure, and heart rate were measured at pre- and post-test and the data were compared among groups and between tests by utilizing two-way ANOVA with repeated measures. Main results of the present study were as follows: 1) Physique and body composition did not change significantly in all groups. 2) Muscular endurance increased significantly in EX+R group, whereas the other physical fitness-related variables showed no significant changes in all groups. 3) Fasting glucose, fasting insulin, HOMA-IR, and HbA1c tended to be improved in EX+R group. 4) AST, ALT, and γ·GT showed no significant changes in all groups. 5) Systolic blood pressure and diastolic blood pressure increased significantly in CON group. Heart rate tended to be decreased in EX+R group and EX group. It was concluded that the 8 weeks of aerobic training and resveratrol supplementation had positive effects on muscular endurance, insulin resistance, and blood pressure in T2DM elderly women. Research investigating the effects of a longer period of aerobic training and resveratrol supplementation on the same variables would be warranted in the future.
The purpose of this study was a investigate the endothelial function of prehypertensive during dynamic exercise. Hypothesis of this study was to impair the endothelial function in prehypertensive compared to normtensive during dynamic handgrip exercise. Eleven healthy prehypertension (24±2 yrs) and ten healthy normotensive (25 ± 2 yrs) were recruited in this study. Participants were performed dynamic handgrip exercise in one contraction per second at 30% of maximum voluntary contraction for three minutes. Vascular (blood vessel diameter, blood flow) and cardiar response (stroke volume, heart rate and cardiac output) were measured at rest and during exercise. Flow mediated dilation (FMD) was decrease significantly in prehypertensive less than normotensive (p<0.05) at rest, and vasodilation of prehypertensive was reduced significantly less than normitensive during exercise (p<0.05). All the cardiovascular responses were aot significantly different at rest and during exercise between prehypertensive and normotensive. These results suggest that endothelial function is impaired in prehypertensive compared to in normotensive
The present study has been carried out with a purpose of a long term estimation for the body size and BMI (Body Mass Index) of Korean children and youth using ARIMA, a time series model. In order to select an estimation model for the optimum time series, among the time series analysis method of SPSS22.0 statistic programs, a multivariate ARIMA (p,d,q) model has been selected that has an input series (physical education facility, time spent for physical education, animal source foods, GDP deflator, animal source food intake ratio), using annual average data of height, weight, and BMI data from 1965 to 2015. Among the several optimal measurements in ARIMA model with estimation variables, an optimal RMSE-based model (RMSE: Root Mean Square Error) has been selected. Using this model, the estimation model and estimated values of children’s height, weight, and BMI have been suggested for each age group. The results are as the following. The trend estimation of height follows a logistic curve, with both male and female groups showing increasing trends. The weight has a trend of increasing ratio higher than height. BMI also shows a trend curve similar to weight. The estimation model has been mostly ARIMA(0,1,0). In particular, the average BMI has been estimated as 22-23 for male students in 6th, 8th, 9th, 11th and 12th grade in 2030. This indicates the recent increasing obesity as children and youth occupy most of daily time for play culture that is far from physical activities, such as computer games, smartphone games, and video games at home.
