It has been known that β-alanine supplementation induce the increment of carnosine in vivo and was effective in delaying fatigue by buffering the hydrogen which was formed during exercise. This study was designed to investigate the effects of 4 weeks of β-alanine supplementation on physical fitness and blood lactate concentration in middle school soccer players. Nineteen middle school soccer players were randomly assigned to either one of two groups, i.e., β-alanine group (n=10) and placebo group (n=9). Subjects in β-alanine group consumed β-alanine 2 g/day during 1st and 2nd week, as well as 3 g/day during 3rd and 4th week, whereas subjects in placebo group consumed maltodextrin in the same manner. All subjects ate same menu and trained same amount at the same training camp during the intervention period. Body composition, aerobic capacity, anaerobic capacity, isokinetic function, and blood lactate concentration during maximal GXT were measured at pre- and post-test. Main results of the present test were as follows: 1) Fat mass and percent body fat decreased significantly in β-alanine group. 2) No significant changes were found in variables related to aerobic capacity in both groups. 3) Average power increased significantly in β-alanine group. 4) Isokinetic muscular endurance increased significantly in β-alanine group. 5) Blood lactate concentration did not change in eithet group; however, blood lactate concentration immediately after maximal GXT in β-alanine group tended to be increased more than placebo group. It was concluded that β-alanine supplementation would have positive effects for improvement of body composition, anaerobic capacity, and muscular endurance in middle school soccer players.
The present study was conducted to determine the effect of contextual interference (CI) and motivational properties (MP) of Knowledge of Result (KR) in learning on relative and absolute timing. Participants (N=48) were randomly assigned to one of four practice groups, which differed in practice structure on CI (blocked, random) and KR on MP (good trial, poor trial). They performed temporal timing tasks in pre-exercise and acquisition phase and went through a retention test and 2 transfer tests after approximately 24 hours. The main findings showed that first, for the relative timing error there was no significant main effect of CI and MP in the acquisition phase, retention, transfer1, and 2 test. However, there was a significant interaction effect between CI and MP in the transfer 2 test. Second, for the absolute timing error there was no significant main effect of CI and MP in the acquisition phase, retention, and transfer test 2 while there was in the transfer test 1. Moreover, there was a significant main effect between CI and MP in the retention, transfer 1, and 2 test. The findings indicated that 1) there was a significant learning effect of absolute timing between KR_good group and KR_poor group on blocked practice in the retention test, 2) random practice schedule and KR_good condition resulted in enhanced absolute timing performance relative to blocked practice and KR_poor respectively at transfer test 1, 3) there was a significant learning effect of absolute timing between KR_good group and KR_poor group on blocked practice at transfer test, 4) KR_good condition could be an useful relative timing learning strategy relative to KR_poor on blocked practice schedule at transfer test 2, effector transfer test. KR-good condition resulted in learning superior to KR_poor group on blocked practice schedule as well. However, there was no significant difference between two conditions on random practice, and 5) there was no difference in the learning effect of absolute timing error between KR_good and KR-poor group in the blocked practice, while there was not in the random practice. It indicated that motivational properties would influence the learning effect of timing in the blocked practice.
The purpose of this study was to find which percentage of 1RM for squat to improve the result of squat jump most effectively after plyometric training with different percentage of 1RM for squat. 24 men in their twenties were measured 1RM for squat and separated in 4 groups by 6 participants. Group A, B, C, and D used 0, 15, 30, and 45% of 1RM, respectively in the plyometric training. All groups had 1 hour training 3 days per week for 8 weeks(24 sessions). This study designed to increase the number of sets of exercises gradually. In week 1 and 2, participants trained 1 set of plyometrics with no load. The number of sets increased 2 to 4 in the week 3-4 to 7-8. The jump height(cm) and vertical impulse(%BW) of squat jump before and after plyometric training were measured by 3D motion capture system and force plate. All 4 groups showed the improvement of squat jump height and vertical impulse, but specially group B was most improved(p<0.5).
Purpose The study was designed to investigate the effects of 12 weeks of circuit training and L-tryptophan supplementation on physical fitness and metabolic syndrome. Methods Forty-one menopausal women were randomly assigned to one of three groups. i.e., combined circuit training and L-tryptophan supplementation group (CT+T: n=14), L-tryptophan supplementation group (T: n=14), and control group (CON: n=13). The subjects in CT+T exercised three sessions per week and took 3g of L-tryptophan per day for 12 weeks. The subjects in T took 3g of L-tryptophan per day for 12 weeks. The subjects in CON were asked to maintain their life pattern for the same period of intervention. Physical fitness and metabolic syndrome-related variables were measured at pre- and post-test. The data were compared by utilizing a repeated two-way ANOVA. Results Main results of the study were as follows: 1) Standing long jump, one leg standing with eyes closed, sit-and-reach, sit-up, and maximal oxygen uptake increased significantly in CT+T. 2) Body weight, body mass index, waist circumference, waist-hip ratio, fat mass, and percent body fat decreased significantly in CT+T. 3) Total cholesterol decreased significantly in CT+T. 4) Fasting plasma glucose (FPG), fasting plasma insulin, and HOMA-IR decreased significantly in CT+T. FPG and HOMA-IR decreased significantly in T. 5) Systolic blood pressure, diastolic blood pressure (DBP), mean arterial pressure (MAP), and rate pressure product decreased significantly in CT+T. DBP and MAP decreased significantly in T. 6) Number of metabolic syndrome risk factors decreased significantly in CT+T and T. Conclusion It was concluded that the circuit training and L-tryptophan supplementation would have positive effects on physical fitness and metabolic syndrome, and that L-Tryptophan supplementation would have positive effects on metabolic syndrome by improving insulin resistance and hypertension in menopausal women.
[Purpose] The purpose of this study was to investigate the process of Jang Changsun’s winning gold medal in the 1966 Toledo World Amateur Wrestling Championship and its meaning. [Methods] Jang Changsun and Katsumura Yasuo who had competed with Jang Changsun for the gold medal were selected as participants, a player and an executive who had participated in the Championship were selected as informants. Data had been collected by in-depth interview were analyzed firstly by using the Patton(1991)’s data analysis method, and the following conclusions were obtained by comparing with preceding studies, press releases, reports etc. [Results] Jang Changsun won a gold medal through the three stages of desperate struggles. The first struggle was to loose weight. Jang Changsun lost three times more weight than other players through fasting treatment, intensive training and dehydration in order to secure an advantageous position in the competition. His second struggle was the sparring itself. He made his mind to win gold medal 2 years before the Championship and started to strengthen his physical fitness and polish up his techniques to fight with strong players from powerful nation of wrestling. He finished the sparring by winning 4 games and tieing 2 games resulting in the same deduction points with Katsumura. It was inevitable for him to fight desperately to lose weight again to get gold medal. He eventually won the gold medal by losing his weight until he fainted because of injuries and serious dehydration. [Conclusion] The first gold medalist Jang Changsun contributed a lot to development of Korean sports by offering chance to consider significance of improving elite player’s exercising environment, scientific coaching, gaining self-confidence to win medal, and realizing the importance of sports informations.
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.
