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.
[Purpose] The study was designed to examine the effects of a 10-week sports climbing training on body composition and surrogate indices of major lifestyle disease in obese elderly women. [Methods] Twenty elderly women, whose percent body fat was over 35%, were randomly assigned into one of two groups, i.e., sports climbing training group (TR: n=10) and control group (CON: n=10). The subjects in TR completed sports climbing training program with 5.8 and 5.9 of difficulty, at 11-13 of ratings of perceived exertion (RPE), 60 min/session, three sessions/wk for 10 weeks. Independent variables regarding body composition and major lifestyle disease, i.e., hypertension, dyslipidemia, and atherosclerosis, were measured and compared between two groups as well as between two tests simultaneously using a repeated two-way ANOVA. [Results] Regarding physique and body composition, there were significant interactions between group and test in body weight, body mass index, fat mass, and percent body fat. These variables decreased significantly in TR. 2) Regarding indices of hypertension, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure decreased significantly in TR. Regarding indices of dyslipidemia, triglyceride decreased significantly in TR. Regarding indices of atherosclerosis, TG/HDL-C ratio decreased significantly in TR. [Conclusions] It was concluded that the 10-week sports climbing training would be beneficial for reduction of body fat despite its’ influence on fat-free mass was limited, and would also contribute on improving surrogate indices of hypertension, dyslipidemia, and atherosclerosis in obese elderly women. Future research investigating the effects of various period, intensity, duration, and frequency of sports climbing training would be warranted.
Purpose The purpose of this study is to investigate the factors for setting proper training duration of frequency that can guarantee the student athletes' right to study and performance, and to derive the ranks of setting proper training duration of frequency of student athletes by school level. Consequently, to provide basic data for the development of training guidelines for the growth period of Korean student athletes. Methods Delphi and Analytic Hierarchical Process(AHP) techniques were used. The Delphi survey was conducted in three phases, and collected data through Delphi survey were computed by SPSS win ver. 22.0 and Excel, using the mean, standard deviation, median, and coefficient of variation. Using the AHP technique, we classified the factors for setting proper training duration of frequency derived through Delphi survey, and calculated the importance by using Microsoft Excel 2010. Conclusion First, elementary students should be guaranteed regular class participation, have basic after school training, and be provided with adequate rest so that they do not lose interest in the exercise. Second, middle school students are required to decide whether to continue exercise based on their ability to exercise and abundant experience. Therefore, when abandoning the exercise, students should be able to faithfully carry out their academic performance. Third, high school students are directly related to college entrance and employment, so they have to concentrate on performance rather than on academic performance.
PURPOSE This study analyzed the difference in lower extremity joint angle and shock absorption patterns at the point of maximum ground reaction force during single-leg drop landing with or without anterior cruciate ligament reconstruction (ACLR). METHODS Forty adult males were recruited for this study, with 19 in the ACLR group (age: 20.52±1.43years, height: 179.26±5.18cm, weight: 74.91±6.29kg) and 21 in the control group (age: 21.42±1.61years, height: 174.97±6.83cm, weight: 69.27±7.56kg). Participants performed single-leg landings on a 30cm tall box. An independent sample t-test was used to analyze the difference in kinetics variables at the point of maximum ground reaction force upon landing, with significance set at p=0.05. RESULTS The lower limb joint angle showed significant differences in hip flexion, hip abduction, knee flexion, and knee valgus (p<0.05) between groups. There was no significant difference between the groups in terms of the results of kinetics variables during single-leg landing (maximum ground reaction force, lower extremity stiffness, and shock absorption time). CONCLUSIONS The ACLR group showed a clear difference in kinematics compared to the control group, but no significant difference in kinetic results was found. The two groups compensated for the same impact with different movements, though movements in the ACLR group may increase the risk of ACL re-injury. Those with ACLR should strive to reduce the risk of re-injury by training to use correct movements.
PURPOSE This study aimed to investigate the effect of an ankle strap on kinetic variables of the lower limb during forward jump landing. METHODS Twelve healthy adult men (mean age, 23.58±2.22 years; mean height, 177.83±5.37 cm; mean weight, 75.00±7.72 kg) participated. The participants stood barefoot on both legs at a horizontal distance of 40% of their body height from the center of the force plate, then jumped forward and landed on the force plate with their dominant or non-dominant leg over a 30-cm hurdle while wearing or not wearing an ankle strap. Joint angle, peak vertical force, loading rate, and leg stiffness were calculated. Paired t-test and repeated-measures two-way analysis of variance with Bonferroni’s post hoc tests were used to compare the characteristics of both lower limbs and the effect of wearing an ankle strap. The significance level was α < .05 RESULTS Our results showed significant differences in kinematic variables between the dominant and non-dominant legs without the ankle strap. With the ankle strap, the inversion angles at the ankle joints of both lower extremities were significantly decreased, and an interaction effect between both legs and the ankle strap occurred in the internal rotation angle of the ankle joint. Kinetic variables did not differ significantly. CONCLUSIONS The ankle strap did not completely compensate for ankle instability in the non-dominant leg, but it significantly reduced the angle of internal rotation at the ankle joint. Thus, we recommend that correct wearing of the ankle strap in sports since it reduces the possibility of lateral ankle sprains to some extent.
Purpose The purpose of this study was to investigate the effects of low-intensity resistance training with blood flow restriction on serum VEGF, bone markers and bone mineral density in elderly women. Methods The subjects were divided into three groups: low-intensity resistance training with blood flow restriction(BFR-LRT, n=8); high intensity resistance training(HRT, n=8); low- intensity resistance training (LRT, n=5). Both the BFR-LRT and LRT groups worked out knee extension and leg curl exercises at 20% of each estimated one-repetition maximum(1RM) and HRT group worked out knee extension and leg curl exercises at 70% of each estimated 1RM 3 days per week for 12 weeks. Results As a result after 12 weeks, serum VEGF level have increased significantly among BFR-LRT group compared to HRT and LRT groups. Serum Bone ALP level have increased significantly among BFR-LRT and HRT groups compared to LRT group. Calcaneus BMD have increased significantly among BFR-LRT and HRT groups compared to LRT group. Conclusions In conclusion, despite using low-intensity load, BFR-LRT is a efficient training alternative to HRT for improving bone metabolism in older women.
This study was designed to examine the effects of 12 weeks of resistance exercise training on physique, body composition, insulin resistance, and blood lipid profiles in 20s normal weight obese females. Sixteen females were randomized into one of following two groups: resistance training group (RT group; n=8) and control group (CON group; n=8). Subjects in RT group completed 12 weeks of resistance exercise training for three times/wk, and subjects in CON group were asked to maintain their normal life pattern during the same intervention period. Data were analyzed using two-way repeated measures ANOVA with post hoc test. Main results of the present study were as follows: 1) Body weight, BMI, waist circumference, hip circumference, WHR, and WHtR decreased significantly in RT group. 2) All variables regarding body composition did not change in both groups; however, fat mass was tended to decrease more in RT group than CON group. 3) Fasting plasma glucose decreased significantly in both groups, whereas other variables regarding insulin resistance did not change significantly in both groups. 4) All variables regarding blood lipids did not change significantly in both groups. Results indicate that 12 weeks of resistance exercise training was beneficial in physique and body composition; however, it was not beneficial in insulin resistance and blood lipid profiles in 20s normal weight obese females. Future research including normal weight obese subjects with higher age would be warranted to elucidate more clearly the effects of resistance exercise training on metabolic status.
[Purpose] A potential issue for wheelchair sports are the characteristics of wheelchair design. The purpose of this review was to investigate the characteristics of design in wheelchair sports including the height of seat, camber and handrim size for improving the performance. [Results] The optimum height of seat related to trunk, arm length and handrim size. The lower seat showed the push efficient highly, while higher seat increased the energy expenditure. In energy expenditure, the optimum height of seat was 100-120° of elbow angle. Handrim size play the role in gear. The smaller handrim size acts like high gear, it gains disadvantages in acceleration, it gains advantages in maximum velocity. On the contrary, the higher handrim size acts like low gear, it gains disadvantages in maximum speed, it gains advantages in acceleration. The ratio of gear consideration in power and velocity. When increased camber enhanced the lateral stability, easier catch the handrim and easier arm motion. So it improved the energy expenditure and push technique. When increased camber enhanced the mechanical efficiency and stability, but it decreased the power. The racing wheelchair camber using the 8° and 10°. [Conclusion] Athletes, coaches and wheelchair experts are provided with insight in the performance effect of key wheelchair design settings, and they are offered a proven sensitive method to apply in sports practice, in their search for the best wheelchair-athlete combination.
PURPOSE This study examined the effects of focus of attention on beginning golfers’ competitive anxiety and motor performance. METHODS Forty-eight college students with no prior golf putting experience were selected as participants and randomly assigned to internal-focus, external-focus, holistic-focus, and control groups (12 participants each). All subjects performed 5-m golf putting in acquisition, noncompetitive, and competitive situations. RESULTS In competitive situations, the internal-focus, holistic-focus, and control groups showed golf putting accuracy and consistency similar to those in noncompetitive situations, whereas the external-focus group’s golf putting accuracy and consistency were significantly lower in competitive situations than in noncompetitive situations. In addition, the holistic-focus group showed significantly higher golf putting accuracy than the control group in both competitive and noncompetitive situations. CONCLUSIONS Holistic-focus can be used effectively as a strategy for beginners to learn motor skills and reproduce learned motor skills when state anxiety increases. However, external attention focus cannot be considered a strategy to induce effective beginners’ exercise performance when competitive state anxiety increases.
PURPOSE The aim of this study was to investigate the effects of 12-week instrumental pilates exercise on isokinetic muscle function and body composition of healthy college women. METHODS Twenty-four college women (aged 21.6±1.3yrs) were recruited to the study. The participants were divided into two groups, as the instrumental pilates group (IPG, n=12) and the control group (CG, n=12). The springboard pilates exercise was conducted 3 times a week for 40~60 minutes during 12 weeks. RESULTS There was significant interaction effects in the right knee and left · right elbow extensor muscles (60°/sec) and left knee flexor and right elbow extensor · flexor muscles (180°/sec)(p<.05, p<.01). There was no significant interaction effects in the muscle mass of the total body, trunk, arms, and legs (NS) and also in the serum growth hormone, insulin-like growth factor-I and 25(OH)Vitamin D (NS). Serum creatine kinase was significantly increased (p<.05). There was also no significant interaction effects in weight, body fat, serum total cholesterol, triglycerides, low & high-density lipoprotein cholesterol (NS). CONCLUSIONS These results suggest that although prolonged instrumental pilates exercise of healthy college women might be improving isokinetic muscle function, there is no increasing effect of muscle mass.
