A KINEMATIC ANALYSIS OF ROUND KICK IN TAEKWONDO

The purpose of this study is to provide kinematic analysis of the round kick in Taekwondo. The round kick is an important component required in the performance of Taekwondo. In order to accomplish this skill, it is necessary to accelerate the movement of the leg to a high velocity. In order to determine the mechanism involved in this maneuver, kinematic analysis of the motion will be used. This study analyzed the round kick motion through application of the 3D-video analysis system. The data determined that the muscles of the thigh initiate the round kick, transmitting force from the hip, through to the shank and finally to the foot. Before kicking the target, the knee-joint flexes to increase the velocity of leg and then the lower limbs extend. These are the requirements for a rapid and powerful kick

Swept blade influence on aerodynamic performance of steam turbine nozzle cascades

To improve the aerodynamic performance of steam turbine nozzle cascades, it is significant to study the effect of swept blades to control the flow field within the cascade. Numerical simulations of three different sweep angle blades (−20°, +20° and 0°) were carried out, using CFD modelling. Simulation results showed that the aft-swept blade can effectively improve the corresponding flow characteristics and reduce the total pressure loss. Meanwhile, it has better aerodynamic performance than the straight blade and the fore-swept blade

Neuroprotective effects of arbutin against oxygen and glucose deprivation-induced oxidative stress and neuroinflammation in rat cortical neurons

In this study, the neuroprotective potential of arbutin (100 µmol L–1) pre-treatment and post-treatment against oxygen/glucose deprivation (OGD) and reoxygenation (R) induced ischemic injury in cultured rat cortical neurons was explored. The OGD (60 min) and reoxygenation (24 h) treatment significantly (p < 0.001) compromised the antioxidant defence in cultured neurons. Subsequently, an increase (p < 0.001) in lipid peroxidation and inflammatory cytokines (tumour necrosis factor-α and nuclear factor kappa-B) declined neuron survival. In pre- and post-condition experiments, treatment with arbutin enhanced both survival (p < 0.01) and integrity (p < 0.05) of cultured neurons. Results showed that arbutin protects (p < 0.05) against peroxidative changes, inflammation, and enhanced the antioxidant activity (e.g., glutathione, superoxide dismutase and catalase) in cultured neurons subjected to OGD/R. It can be inferred that arbutin could protect against ischemic injuries and stroke. The anti-ischemic activity of arbutin can arrest post-stroke damage to the brain

PO-208 Effect of resistance training on functional fitness and bone mineral density in elderly women

Objective Try to carry out the intervention experiment of the strength exercise of the elderly in the community, aiming to provide theoretical and data basis for the daily strength exercises of the elderly in China. Methods &nbsp;Recruiting 18 elderly female volunteers in Xicheng District, Beijing, required independent living ability and were willing to participate in the experiment. They were randomly divided into intervention group (N=9, 62.0±6.0 years) and control group (N=9, 63.0 ± 4.8 years). On Tuesday afternoon and Thursday morning, under the leadership of a professional coach, follow the planned "Resistance Exercise Plan" to carry out resistance training. Each practice time is about 90min for 9 weeks. The exercise intensity control is divided into two phases: the first phase lasts for one week, mainly the learning and adaptation phase of the action, and the heart rate control in the 30%~40%HRR or RPE 10 subscale is 4 (a little easy); The stage lasts for 8 weeks of the medium-intensity practice phase, the heart rate control in the 40%~60%HRR or RPE 10 subscale is 5~6 (moderate, slightly strenuous). Results Intervention group before and after experiment, the grip strength (25.0±5.0 VS 26.8±3.9 kg, P&lt;0.05) and the 30s arm curl test (23.1±5.2 VS 25.4±4.0 reptitions, P&lt;0.05) increased. Five sit-up tests (6.99±2.01 VS 6.51±2.00 s, P&lt;0.05) and the 8-foot standing walk (5.13±1.03 VS 5.07±1.01 s, P&lt;0.05) were all shortened. The bone density T value (-1.3±0.4 VS -1.0±0.4, P&lt;0.05) increased. After intervention, the intervention group compared with the control group, grip strength (26.8 ± 3.9 VS 22.1 ± 4.5 kg, P &lt;0.05), 30s arm curl test(25.4 ± 4.0 VS 22.1 ± 3.0 reptitions, P &lt;0.05) increased. Five sit-up tests (6.51 ± 2.00 VS 6.94 ± 1.05 s, P &lt; 0.05) and 8 feet of standing walk (5.07 ± 1.01 VS 5.27 ± 0.97 s, P &lt; 0.05) were all shortened. Bone density T value (-1.0 ± 0.4 VS - 1.4 ± 0.4, P &lt; 0.05) increased. There was no significant change in the 30-second chair stand test. Conclusions Through 9 weeks of progressive resistance exercise, the experiment made the upper limb explosive force, upper limb muscle endurance, lower limb explosive power, flexibility and dynamic balance enhanced, and bone density increased. The enhancement of lower limb endurance is not obvious, which may be the reason for short experimental time and small exercise intensity of lower limbs

PO-192 Comparative Study on Screening Results of Functional Movements of Middle-aged and Old Women before and after Square Dance Exercise: There is no full text article associated with this abstract

Objective This study will conduct a functional action screening (FMS) test for middle-aged and older women who participate in square dances, and explore the influence of square dance exercise on the screening results of middle-aged and older women, and provide reference for women's square dance exercise. Methods Experimental method: A 12-week weekly square dance exercise was conducted on middle-aged and elderly women who participated in the square dance exercise. The functional action screening results of the experimental subjects before and after the experiment were tested and compared. Results 3.1 &nbsp;&nbsp;Functional screening results of middle-aged and older women before exercise The average functional screening results of middle-aged and older women before exercise were 13.70±2.518. The shoulder flexibility score of middle-aged and old women was 2.55±0.711, the average score of leg flexibility was 2.55±0.506, and the average score of trunk stability of middle-aged and old women was 1.79±0.485, and the rotational stability was 1.70±0.529. The scores of the front and rear leg squatting modes were 1.58±0.663, the scores of the hurdles were 1.97±0.305, and the scores of the squatting mode were 1.76±0.792. 3.2&nbsp; Changes in functional action screening results of middle-aged and elderly women after the experiment After exercise, the squat action mode score was 1.39±1.088, the hurdle step action mode score was 2.30±0.529, the front and rear leg squat action mode was 1.82±0.769, and the shoulder flexibility was 2.36±0.895. The knee lift leg score was 2.36±0.549, the trunk stability score was 1.52±0.870, the rotational stability score was 1.88±0.415, and the total score was 13.67±2.847. 3.3&nbsp; &nbsp;Comparison of screening results before and after exercise After the experiment, the total scores of FMS test indicators, shoulder flexibility, trunk stability, rotational stability, squat movement mode and front and rear leg squat mode were not significantly changed (P = 0.951, 0.311, 0.119, 0.056, 0.070 and 0.118 respectively). The hurdle step movement mode was significantly improved, and the mean increased from 1.97 to 2.30 points (p&lt;0.01). Conclusions 4.1 The functional quality of middle-aged and older women who participate in square dance exercises is generally not high. 4.2 Once a week, 2 hours of 12-week square dance exercise can effectively improve the walking movement mode of middle-aged and older women. 4.3 Once a week, 2 hours of 12-week square dance exercise can not effectively improve the upper and lower limb flexibility, core stability and squat and front and rear leg movement modes of middle-aged and older women. 4.4 &nbsp;&nbsp;Middle-aged and older women who participate in square dance exercise need to add functional training in a targeted manner, instead of relying solely on square dance

Non-zero Integral Spin of Acoustic Vortices and Spin-orbit Interaction in Longitudinal Acoustics

Spin and orbital angular momenta (AM) are of fundamental interest in wave physics. Acoustic wave, as a typical longitudinal wave, has been well studied in terms of orbital AM, but still considered unable to carry non-zero integral spin AM or spin-orbital interaction in homogeneous media due to its spin-0 nature. Here we give the first self-consistent analytical calculations of spin, orbital and total AM of guided vortices under different boundary conditions, revealing that vortex field can carry non-zero integral spin AM. We also introduce for acoustic waves the canonical-Minkowski and kinetic-Abraham AM, which has aroused long-lasting debate in optics, and prove that only the former is conserved with the corresponding symmetries. Furthermore, we present the theoretical and experimental observation of the spin-orbit interaction of vortices in longitudinal acoustics, which is thought beyond attainable in longitudinal waves in the absence of spin degree of freedom. Our work provides a solid platform for future studies of the spin and orbital AM of guided acoustic waves and may open up a new dimension for acoustic vortex-based applications such as underwater communications and object manipulations