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Given that motions of 1 segment affect those of an adjacent segment, the authors of biomechanical studies must thoroughly investigate the kinematics and kinetics of the proximal joints (hip and knee) as well as the ankle joints in patients with chronic ankle instability (CAI). However, few researchers have investigated the altered movement strategies of the lower extremities of patients with CAI compared with lateral ankle-sprain (LAS) copers and control participants throughout the full gait cycle of walking and jogging. To evaluate lower extremity biomechanical differences in patients with CAI, LAS copers, and control individuals during gait. Case-control study. Controlled laboratory setting. A total of 54 participants, consisting of 18 patients with CAI (age = 24.6 ± 2.8 years, height = 173.0 ± 8.0 cm, mass = 67.8 ± 14.6 kg), 18 LAS copers (age = 26.0 ± 4.6 years, height = 173.4 ± 7.5 cm, mass = 66.9 ± 10.3 kg), and 18 control individuals (age = 26.2 ± 2.3 years, height = 172.2 ± 8.2 cm, mass = 63.3 ± 11.2 kg). Three-dimensional kinematics and kinetics of the lower extremity during walking and jogging. The CAI group exhibited dorsiflexion deficits and more inverted ankles compared with the LAS coper and control groups during walking and jogging. In addition, the LAS coper group generated greater knee internal-rotation moments than did the CAI group during jogging. The other variables did not differ among groups. Participants with CAI demonstrated altered biomechanics, which need to be addressed via intervention programs. [ABSTRACT FROM AUTHOR]

Para taekwondo is a combat sport martial art that requires fast reaction times for successful defense during fighting. The current classification system is based on the function and the effective length of the upper limbs, which affects the athlete's ability to block. Therefore, this study aimed to investigate the differences between the different classes in the athlete's ability to block and move around the ring. A total of 87 Para taekwondo (K42, K43, and K44) athletes' data were analyzed. Each participant engaged in the blocking reaction time test in a fighting stance with the left leg in front, the right leg in front, and the legs parallel in random order. A foot-stepping reaction test was performed to anlyze how the athletes moved in various directions. The results indicated no significant differences between the classes for the lower body foot stepping reaction times and the upper body blocking performance times. The stimulated blocking time of the Para taekwondo athletes ranged from 0.79 to 0.97 s Furthermore, the neurological group (0.86 ± 0.09 s) was significantly slower than the amputation/dysmelia group (0.81 ± 0.07 s). We thus concluded that the neurologically impaired athletes were disadvantaged and therefore belonged in a separate class. [ABSTRACT FROM AUTHOR]

This study aimed to verify the relationship between ideal sleep duration and physical fitness in South Korean adults and older adults. The secondary analysis data of 2,832 adults (19–64 years) and 629 older adults (65 years and above), obtained from the 2015 National Fitness Survey, were analyzed. Participants completed various physical fitness tests (grip strength, sit-ups, standing long jump, 50 m dash, sit-and-reach, and 20 m shuttle run in adults; grip strength, sit-up, sit-to-stand, sit-and-reach, back-scratch, one-leg standing test, and 6-minute walk in older adults) and were divided into four groups based on self-reported sleep duration. Group differences in physical fitness variables were analyzed with one-way analysis of variance, and Pearson's correlation was used to verify the relationship between sleep duration and physical fitness; statistical significance was set at p <.05. In adult males, there was a positive correlation between explosive muscular strength (standing long jump) and sleep duration (p =.046), whereas in adult females, there was a negative correlation between cardiopulmonary endurance (20 m shuttle run) and sleep duration (p =.026). However, in older adults, there was no significant correlation between sleep duration and physical fitness (p >.05). Further, across the sample, there were no significant group differences in physical fitness variables. A positive correlation exists between sleep duration and muscular strength in adult males and a negative correlation between sleep duration and cardiorespiratory endurance in adult females. Designing sleep and exercise programs based on these results may improve physical fitness among adults and older adults. Future studies that include controlled variables that affect physical fitness and sleep patterns are warranted. [ABSTRACT FROM AUTHOR]

Taekwondo epidemiology studies have been in short supply since the rule changes introduced by World Taekwondo in 2017. To describe injury and illness patterns at the 2017 World Taekwondo Championships (WTC) in Muju, South Korea, after the implementation of the web-based surveillance system by World Taekwondo. Prospective cohort study. All injuries and illnesses were recorded during the 2017 WTC using a web-based system developed by the International Olympic Committee. A total of 971 athletes who participated in the 2017 WTC. Profiles and mechanisms of injury and illness in the 2017 WTC. We analyzed a total of 131 injuries and 26 illnesses, corresponding to an overall clinical incidence of 13.5 (95% CI = 11.2, 15.8) injuries and 2.7 (95% CI = 1.6 3.7) illnesses per 100 athletes and an overall incidence rate of 19.3 (95% CI = 16.0, 22.6) injuries and 3.8 (95% CI = 2.4, 5.3) illnesses per 1000 athlete-days. Most injuries occurred in the lower extremities (n = 61, 46.6%), and knee injuries were most frequent (n = 26, 19.8%). Among head and trunk injuries (n = 39, 29.8%), face injuries (n = 32, 24.4%) were most common, whereas among upper extremity injuries (n = 31, 23.7%), finger injuries (n = 8, 6.1%) were seen most often. Contusions (n = 44, 33.6%) were the most frequent injury type, followed by fractures and ligamentous ruptures or sprains. The most common injury mechanism was contact with another athlete (n = 97, 74.0%), whereas the least common was concussion (n = 5). The major affected system was the respiratory system (n = 11, 42.3%), with major symptoms being pain (n = 11, 42.3%) and fever (n = 7, 26.9%). Environmental factors were the most typical cause of illness (n = 15, 57.7%). The web-based surveillance system used at the 2017 WTC revealed that 13.5 per 100 athletes (77.8/1000 athlete-exposures, 13.9/1000 minute-exposures) had new or recurrent injuries, whereas 2.7 per 100 athletes became ill. [ABSTRACT FROM AUTHOR]

Objective: This study aims to compare and analyze the difference of impact force attenuation according to size and impact location on a Taekwondo body protector.Methods: Body protectors sized 1 to 5, were impact tested by equipment based on the specifications in the European standard manual (EN 13277-1, 3). The impactor release heights were set to match impact energies of 3 and 15 J. The impactor was made from a 2.5 kg cylindrically cut piece of aluminum. Each body protector was impacted 10 times at the two impact energies and two locations. The differences in performance for each body protector size were compared using a two-way analysis of variance with a significance level of p< 005. The effect sizes were investigated using a partial eta squared value (η2).Results: The significant mean differences between the body protector size and impact area (p< 005) and the average impact time of impact strengths 3 and 15 J were 0.0017 and 0.0012 s, respectively In addition, when an impact strength of 15 J was applied, the maximum resulting impact force exceeded 2000 N for both locations on all sizes. Furthermore, at an impact strength of 3 J size 3 significantly reduced the impact force more than the other sizes; however, size 1 showed the greatest shock absorption at an impact of 15 J.Conclusion: The results of this study show that the shock absorption of body protectors does not increase according to size; i.e., a larger body protector does not reduce the impact load more effectively. To improve safety performance, we recommend a maximum impact force of 2000 N or less for all body protectors. [ABSTRACT FROM AUTHOR]

Although previous studies have examined the relationship between smoking and physical fitness, they only considered current smoking status and the same fitness measurements regardless of age. This study investigated differences in physical fitness based on tobacco smoking habits. A total of 2830 non-elderly adults (NEA; 19–64 years) and 629 elderly (65–89 years) participated in the study, using data extracted from a Korean national database. One-way ANCOVA and ANOVA were conducted to analyze the results. The subjects were classified into three groups (smokers, those who had quit, and never-smokers). In NEA men, a significant difference was observed in 50-m dash (p = 0.003) and 20-m shuttle-run (p < 0.001), while in elderly men differences were only seen in sit-ups (p = 0.015). In the case of NEA and elderly women, no significant differences were observed in physical fitness levels (p > 0.05). The decreased fitness level due to smoking was more noticeable in men than in women, and in NEA more than in elderly persons. A non-smoking policy and customized training based on age or gender are necessary to increase fitness and improve health conditions. [ABSTRACT FROM AUTHOR]

The authors have developed a semitransparent, multilayered cathode of indium tin oxide (ITO)/Ag/tungsten oxide (WO3) for transparent organic light-emitting diodes. The device showed a weak negative differential resistance (NDR), until the operating voltage of 8 V was reached. NDR was due to the resonant tunneling by both the quantum barrier and quantum well. The silver oxide (Ag2O) on the Ag metal was confirmed by x-ray photoelectron spectroscopy, and the energy levels of Ag2O were quantized due to the quantum size effect and this produced the resonant tunneling channels. The device using ITO/Ag/WO3 with a LiF/Al bilayer was superior to those devices which only used ITO or WO3, mainly because the out coupling was enhanced by employing a WO3 material, which is much more transparent than ITO. [ABSTRACT FROM AUTHOR]

A semitransparent cathode of indium tin oxide (ITO)/Ag/ITO was developed as a resonant tunneling double barrier structure for transparent organic light-emitting diodes. A weak negative differential resistance was observed in devices using a 100 nm thick ITO/Ag/ITO layer as a cathode in combination with a thin LiF/Al layer. The current injection of devices was dominated by resonant tunneling, which induced no luminance at low voltage. This was achieved by employing an e-beam evaporated ITO/Ag/ITO cathode due to the double quantum barriers of ITO and the quantum well of Ag. The authors also applied the multilayer cathode to small molecule devices, which showed the same resonant tunneling currents. [ABSTRACT FROM AUTHOR]

Background: Para taekwondo has only recently been added to the Paralympic games scheduled to be held in 2021; however, there is limited research on the classification of the para taekwondo athletes. This study aimed to provide details on the impairments and disabilities of the para taekwondo players. The secondary objective was to investigate the relationship between some of the proposed factors and the athletes' rankings., Methods: The data of 556 para taekwondo athletes (119 females and 437 males), who had been classified over the past 5 years, were analyzed., Results: The K44 class was the most popular, and 61% of the classified athletes belonged to this class. Acute injury from trauma was the most frequent cause of impairment, and 62.3% of all impairments/disabilities occurred during 0-5 years of age. Approximately 28% of the athletes had <1 year of training prior to international competitions. One-way analysis of variance performed for the combined length of the upper limbs showed significant differences (F(3,311)=455.78, P<0.001) among the K41-K44 classes. There were weak correlations (ρ<0.1) between the ranking and the age of the disability/impairment onset, combined length of the upper limbs, and type of disability., Conclusions: Continued data collection that provides insights into the impairment profiles of para taekwondo athletes is needed to improve the current classification system in order to enhance the safety and fairness.

The objective of the study was to evaluate and compare different brands of forearm, shin, hand and foot protective equipment used in Taekwondo. The most popular brands of large forearm, shin, hand and foot protectors (D ® , A ® , K ® ), approved by the World Taekwondo and Korean Taekwondo Association, were examined. A drop test was used to test the protective equipment using impact levels of 3J, 9J, 12J and 15J for the forearm and shin guards, and 3J and 9J for the hand and foot protectors. The protective equipment was hit ten times from each of the designated drop heights. The drop test is described in the European standards manual of protective equipment for martial arts (SRPS EN 13277-2). The maximum force (MF) and impulse were lowest for brand K ® (2610.3 ± 1474.1 N), and brand A ® (9.6 ± 3.1 Ns), respectively, for the forearm guards; for brand A ® (2053.4 ± 1267.1 N) and brand K ® (9.8 ± 3.5 Ns), respectively, for the shin guards; for brand K ® (4486.5 ± 1718.4 N), and brand A ® (6.3 ± 1.1 Ns), respectively for the hand protectors; and for brand A ® (3733.7 ± 2465.3 N), and brand D ® (6.8 ± 0.6 Ns), respectively, for the foot protectors. For the forearm guard brand and impact level, there was a significant interaction effect for the MF (F=42.44, η 2 =.677, p <0.001) and impulse (F = 33.97, η 2 = 0.626, p <0.001). Based on the MF, brand K ® performed the best for the forearm guards and hand protectors, and brand A ® , for the shin guards and foot protectors. The best results for the impulse were for brand A ® (forearm guards and hand protectors), brand K ® (shin guards) and brand D ® (foot protectors).

Objective: To describe the effects of proprioceptive training on pain, stiffness, function, and functional test outcomes among patients with knee osteoarthritis (OA)., Data Sources: All studies completed from 1946 to 2017 were obtained from 4 databases (PubMed, MEDLINE, CINAHL, and SPORTDiscus)., Study Selection: Three reviewers independently identified appropriate studies and extracted data., Data Extraction: Methodologic quality and level of evidence were assessed using the Physiotherapy Evidence Database scale and Oxford Centre for Evidence-Based Medicine guidelines. The standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for pain, stiffness, function, and functional test outcomes., Data Synthesis: Seven randomized controlled trials involving 558 patients with knee OA met the inclusion criteria. The selected studies had Physiotherapy Evidence Database scores of 6 to 8. All randomized controlled trials had an Oxford Centre for Evidence-Based Medicine level of evidence of 2. Meta-analysis of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale (SMD = -0.56; 95% CI = -1.06, -0.07; P = .026), function subscale (SMD = -0.40; 95% CI = -0.59, -0.21; P < .001), and non-WOMAC walking speed test (SMD = -1.07; 95% CI = -2.12, -0.01; P = .048) revealed that proprioceptive training had significant treatment effects. Proprioceptive training was not associated with reductions in WOMAC stiffness subscale scores and did not improve non-WOMAC get-up-and-go scores., Conclusions: Proprioceptive training effectively promoted pain relief and completion of functional daily activity among patients with knee OA and should be included in rehabilitation programs. Stiffness and other mobility measures were unchanged after proprioceptive training. Modified proprioceptive training programs are needed to target stiffness and improve additional physical function domains.

Background and Objectives: Obesity is a chronic disease that requires good eating habits and an active life style. Obesity may start in childhood and continue until adulthood. Severely obese children have complications such as diabetes, hypercholesterolemia, hypertension and atherosclerosis. The goal of this study was to determine the effects of exercise programs on anthropometric, metabolic, and cardiovascular parameters in obese children., Subjects and Methods: Fifty four obese children were included. Anthropometric data such as blood pressures, body mass index (BMI) and obesity index (OI) were measured. Blood glucose, total cholesterol, triglycerides, low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT), high sensitive-CRP (hs-CRP), brachial-ankle pulse wave velocity (BaPWV) and ankle brachial index (ABI) were measured. Physical fitness measurements were done. Obese children were divided into three groups: an aerobic exercise group (n=16), a combined exercise group (n=20), and a control group (n=18). Obese children exercised in each program for 10 weeks while those in the control group maintained their former lifestyle. After 10 weeks, anthropometric data and cardiovascular parameters were compared with the data obtained before the exercise program., Results: LDL-C, waist circumference, and systolic blood pressure decreased significantly in the aerobic exercise group compared to the control group (p<0.05). Waist circumference and systolic blood pressure decreased significantly in the combined exercise group compared to controls (p<0.05). Physical fitness level increased significantly after the exercise programs (p<0.05 vs. control). PWV did not show a significant change after exercise., Conclusion: A short-term exercise program can play an important role in decreasing BMI, blood pressure, waist circumference, LDL-C and in improving physical fitness. Future investigations are now necessary to clarify the effectiveness of exercise on various parameters.