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Recent literature has highlighted altered spinal-reflex excitability following acute lateral ankle sprain (ALAS), yet there is little information on the conduction velocity of spinal reflex pathways (CV-SRP) in these patients. Therefore, we aimed to investigate the effects of ALAS on the CV-SRP. We employed a cross-sectional study with two groups: ALAS (n = 30) and healthy controls (n = 30). The CV-SRP of the soleus, fibularis longus, and tibialis anterior was assessed using the H-index method. As secondary outcomes, H-reflex and M-wave latencies were assessed as well as acute symptoms including ankle swelling, pain, and self-reported ankle function. Separate group-by-limb ANOVA with repeated measures revealed a significant interaction for soleus CV-SRP (p < 0.001) and H-reflex latency (p < 0.001), showing significant slower CV-SRP and longer H-reflex latency in the involved limb of the ALAS group compared with both limbs in the control group. However, there was no significant interaction or main effect in any other ankle muscles (p > 0.05). A further correlation analysis showed a significant relationship between CV-SRP and acute symptoms, including ankle swelling (r = −0.37, p = 0.048) and self-reported ankle function (r = 0.44, p = 0.017) in ALAS patients. These results suggest a disrupted functionality of the afferent pathway and/or synaptic transmission following ALAS. Level of Evidence: 4.

본 연구는 키즈런 프로그램의 현안을 살펴보고, 초등 체육으로 정착하기 위해 필요한 발전 방안을 모색하는데 목적이 있다. 이를 위해 SWOT 분석을 통해 발전방안을 모색하고자 했다. 연구대상자는 전임지도자 3명과 초등교사 3명으로 인터뷰는 2020년 3월 7일부터 5월 12일까지 약 두 달간 실시했다. 면담시간은 평균 40분 이내로 소요됐으며, 코로나 상황에 따라 일부 비대면 면담도 한 두차례 실시했다. 모든 분석결과는 연구대상자의 e-mail이나 카카오톡으로 Memner Check를 받았다. 연구결과 첫째, 키즈런 프로그램의 강점은 체육과 교육과정이 개정되는 동안 단 한차례의 변화가 없었던 점, 매년 고정적으로 정부지원이 이루어진 점, KAAF이라는 공인 스포츠기구가 직접 유소년 스포츠를 운영한다는 점, 뉴스포츠임에 따라 전문성을 크게 요구하지 않다는 점이다. 둘째, 키즈런 프로그램의 약점은 수업권이 전혀 없는 육상 전임지도자에게 의존도가 지나치게 높은 점, KAAF을 포함한 시도육상연맹의 관료주의, 정부 예산항목에 보급에 대한 지원이 제한된 점, 핵심 대상인 초등교사에 대한 홍보 및 연수 부족 등이다. 셋째, 키즈런 프로그램의 기회는 스포츠 인성교육의 관심이 증가한 점, 초등학생의 건강체력 관심 증가한 점, 지자체 관련 행사 추진 가능한 점, IAAF 주도로 국제 네트워크를 형성할 수 있다는 점, 여교사 교직문화에 프로그램이 최적한 되었다는 점 등이 있다. 넷째, 학교스포츠클럽 운영 종목으로 채택되지 않다는 점, 다양한 뉴스포츠들이 초등 체육 교과서에 소개되었다는 점, 초등 체육교사들의 육상 종목에 대한 부정 여론이 존재한다는 점 등이 있다. 따라서 KAAF이 관료주의 행정에서 벗어나 초등교사의 입장에서 사업을 다각화한다면, 엘리트 스포츠의 또 다른 혁신으로 기억될 수 있을 것이다.

Neural changes in the ankle stabilizing muscles following ankle sprains are thought to be one contributing factor to persistent ankle dysfunction. However, empirical evidence is limited. Therefore, we aimed to examine spinal reflex excitability of lower leg muscles following acute ankle sprains (AAS). We performed a case-control study with 2 groups consisting of 30 young adults with AAS and 30 aged-matched uninjured controls. Hoffmann reflex (H-reflex) testing was performed to estimate spinal reflex excitability of lower leg muscles: soleus, fibularis longus (FL), tibialis anterior (TA). Maximal H-reflex (Hmax) and motor responses (Mmax) were determined by delivering a series of electrical stimuli at the sciatic nerve. Hmax/Mmax ratios were calculated to represent normalized spinal reflex excitability. Separate group-by-limb analyses of variance (ANOVA) with repeated measures found there were no significant interactions for any of the muscles (SL: F1,56 = 0.95, p = 0.33, FL: F1,51 = 0.65, p = 0.42, TA: F1,51 = 1.87, p = 0.18), but there was a significant main effect of group in the soleus (F1,56 = 6.56, p = 0.013), indicating the Hmax/Mmax ratio of soleus in the AAS group was significantly lower bilaterally (AAS = 0.56 ± 0.19, control = 0.68 ± 0.17, p = 0.013), with no significant group differences in the other muscles (FL: F1,51 = 0.26, p = 0.61, TA: F1,51 = 0.93, p = 0.34). The bilateral inhibition of the soleus spinal reflex excitability following AAS may be significant in that it may explain bilateral sensorimotor deficits (postural control deficits) following unilateral injury, and provide insights into additional therapies aimed at the neural change.

The primary purpose of the present study was to re-visit HRmax prediction by two commonly used equations (i.e., Fox′s and Tanaka′s equation) compared to the direct measured HRmax using the large sample size of Asians. The second aim of the study was to focus on suggesting new equations for the Asian population by separating gender and specific age groups. A total of 672 participants aged from 7 to 55 years were recruited for the study (male: 280 and female: 392), and the maximal graded exercise test with Bruce protocol was used to measure HRmax. All data obtained from the study were analyzed by SPSS 25.0. Additionally, three statistical analysis methods (i.e., Mean Absolute Percent Errors (MAPE), Bland–Altman plots, and equivalence testing) were utilized to confirm the consistency between the measured HRmax and the two prediction equations. The main finding was that two equations showed significant differences in predicting the HRmax of Korean aged from 7 to 55 years. The outcome of children aged from 7 to 14 was a different fit in the agreement compared to other age groups. Fox′s equation had the best fit in the average of the difference closer to zero and completely included within the equivalence zone, but females over 15 years old revealed higher errors than males in the values calculated by the two equations compared to the direct measured HRmax. Consequently, the study demonstrated that both equations tended to overestimate the HRmax for males and females over 15 years old, and the two universal equations were not suitable to predict the HRmax of Koreans except for children aged from 7 to 14 years. The new HRmax prediction equations suggested in this study will more accurately predict the HRmax of Asians, and additional analyses should be examined the cross-validity of the developed HRmax equation by age and gender in the future study.

Holtgeerts, RN, Gann, J, Jung, HC, and Hey, W. The impact of recovery time on performance in Division I collegiate beach volleyball players. J Strength Cond Res 36(3): 667-673, 2022-The sport of beach volleyball has recently grown significantly at the collegiate level, and collegiate beach volleyball players often practice and compete 5 or 6 days per week during the competitive season. This study examined the effects of the amount of recovery time on performance in Division 1 Collegiate beach volleyball players. Ten female NCAA Division 1 beach volleyball players, aged 20.2 ± 1.23 years, participated in the study. Subjects completed 2 trials consisting of 4 sessions of volleyball play (with a 24-hour recovery trial and 48-hour recovery trial). Trials were randomized and counter balanced. Each trial measured counter-movement jump, 5-10-5 agility time, 3 beach volleyball drills, and scores of a beach volleyball match. Perceived recovery, sleep quality, and rating of perceived exertion were also recorded. The significance level set for the study was p ≤ 0.05. Counter-movement jump showed small but significant increases following the 24-hour recovery period (p ≤ 0.05). 5-10-5 agility test showed significant improvement with the 48-hour recovery period (p ≤ 0.05). Perceived Recovery scores demonstrated significant increases in both recovery periods (p ≤ 0.05). Beach volleyball drill and match performance were not affected by the change in recovery time. These results indicate that, although some physical skills are affected by recovery time, beach volleyball performance as a whole is relatively stable over several days. It is normal for NCAA athletes to play back-to-back days and with little recovery time, and these results indicate that this practice does not negatively affect sport performance.

The combat sports athletes developed great gains in both muscular function and fatigue resistance by utilizing high-intensity interval training (HIIT). However, it has not fully investigated whether the different work-to-rest ratios of HIIT show the effectiveness on muscle function in adolescent athletes. The purpose of the study was to compare different work-to-rest ratios by applying different rest times in response to the identical work time during HIIT on muscle function in adolescent Taekwondo athletes. Forty-seven adolescent male Taekwondo athletes (age: 16.7±0.8 years) were randomly assigned to the control group (n=11) vs. three HIIT groups by work-to-rest ratios; 1) 1:2 [30s:60s] (n=12), 2) 1:4 [30s:120s] (n=12), and 3) 1:8 [30s:240s] (n=12). All groups completed 10 experimental sessions over four weeks, while the control group maintained their regular Taekwondo training. Muscular functions were measured by assessing isokinetic muscle strength and endurance of the knee extensor and flexor. The participants performed three sets of twenty maximal extension and flexion contractions at 120°s-1 with a 1-min interval between the sets for fatigue resistance. Blood samples were collected to measure free-testosterone, cortisol, creatine kinase, and urea as stress-to-recovery indicators. A positive effect on improving muscle fatigue resistance was observed at the first set of assessments in the HIIT with 1:4 (Δ10.2%, p

This study examined the effects of a non-caffeinated energy drink (ED) that contained calamansi juice, glucose, and taurine on 3-km running performance and recovery. Eleven NCAA Division I middle-distance runners (20.8 ± 1.5 years old) were randomly assigned to consume either the ED or a placebo drink 60 min before 3-km running on a 400-m official track. Performance time and speed were recorded every 500-m interval. Recovery blood lactate concentration (BLC), systolic (SBP), diastolic blood pressure (DBP), and heart rate (HR) were measured at baseline, 60-min after ingesting the drinks, and post-running measurements were performed at 1-min, 5-min, and 10-min. Repeated analysis of variance and paired t-test were applied to examine the effects of time, trials, and their interaction on performance and recovery. Statistical significance was set a priori at p &lt, 0.05. No significant difference was observed in performance time and speed between trials (p &lt, 0.05). No interaction effect was found on performance time, speed, recovery BLC, DBP, and HR (p &lt, 0.05). However, an interaction effect for trial by time was observed on SBP (p = 0.01). Recovery SBP continues to decrease from 5-min to 10-min in the ED trial (∆ = −13.9·mmHg) and slightly increased in the placebo trial (∆ = 1.1·mmHg). This study suggests that acute consumption of a calamansi-containing ED can positively impact the SBP recovery but not running performance. Further studies are needed to examine the acute and chronic effects of this ED on exercise performance and recovery among different populations.

Hydroplaning phenomenon is one of the major factors that must be considered to ensure safe driving on wet road surfaces. In this paper, the approach to numerical simulation of the physical hydroplaning characteristics using patterned tire is described. A detailed 3-D patterned tire model is constructed by in-house modeling program and the water flow is considered as incompressible. The complex tire material compositions are effectively modeled using composites, and rubber properties generalize the Mooney-Rivlin model. The finite element method (FEM) and the advanced finite volume method (FVM) are used for structural and for fluid-tire interaction analysis, respectively. Performance prediction of hydroplaning via coupling of computational fluid dynamics (CFD) and FEM has delivered a detailed insight into the local mechanisms and root causes of hydroplaning. Numerical examples were verified by comparing the experimental test results and it is confirmed to indicate similar correlation tendency and high reliability. The effect of driving velocity, pattern groove size, and pattern direction on hydroplaning phenomenon of tire is discussed and logical results were obtained.

This study examined the effects of resistance training on muscle quality, muscle growth factors, and functional fitness in older adult women with sarcopenia. Twenty-two older adult women aged over 65 with sarcopenia were randomly assigned to either resistance training (RT, n = 12) or non-exercise control group (CG, n = 10). The body weight-based and elastic band RT were performed three times a week, 60 min per session, for 16 weeks. Body composition and thigh muscle quality were estimated by dual-energy X-ray absorptiometry (DEXA) and computed tomography (CT), respectively. The muscle growth factors, including growth differentiation factor-8 (GDF-8), growth differentiation factor-15 (GDF-15), activin A, and follistatin, were analyzed via blood samples. Statistical analyses were performed using repeated measures multivariate analysis of variance (MANOVA), analysis of variance (ANOVA), and effect size (i.e., cohen’s d, partial eta square), and the significance level was set at 0.05. The RT group improved their functional fitness, grip strength, gait speed, and isometric muscle strength (p &lt, 0.01, d &gt, 0.99, large), while these variables did not change in the CG. An increase in intramuscular fat was only observed in the CG (p &lt, 0.01, 1.06, large). Muscle growth factors such as follistatin were significantly increased in the RT (p &lt, 0.05, 0.81, large), but other variables did not change following resistance training. Sixteen weeks of resistance training improved functional fitness and prevented age-related increases in intramuscular fat in the thigh area. However, there were only some changes in muscle growth factors, such as follistatin, suggesting that the effectiveness of resistance training on muscle growth factors is limited. Body weight-based and elastic band resistance training is an alternative training method for sarcopenia to minimize the age-related adverse effects on muscle function and quality.

The current study examined the differences in health-related physical fitness (HRPF), physical activity (PA), and sedentary behavior (SB) between adolescents with and without ongoing respiratory diseases (RD). This study’s participants were from 12 to 15 years old (7th–10th grade) in South Korea. Adolescents with RD were selected through RD-related questions (i.e., asthma, rhinitis, sinusitis, and bronchitis) (n = 139), in contrast, adolescents without RD, randomly selected from the general group, responded to any health problem-related questions as “No” (n = 139). HRPF was measured based on the FITNESSGRAM and EURO FIT test batteries and the measurements of HRPF included cardiovascular endurance, muscular strength, muscular endurance, flexibility, and body composition. All statistical analyses were conducted by SPSS 25.0, and the independent t-test was used to compare the HRPF and PA between the two groups. Moreover, the measured HRPF was compared with a series of analyses of three-way ANOVAs (age × gender × group). Adolescents with RD had a positive association with less participation in PA (p &lt, 0.05, RD: 3081.81 ± 4793.37, general: 2073.64 ± 3123.47) and with more time spent on SB (above 12 h per week: RD group (38.85%) and general group (33.09%)). Furthermore, adolescents in the RD group showed significant effects on all components of HRPF (p &lt, 0.05). Our study confirmed that HRPF is an essential predictor of adolescents’ health outcomes, especially for those with RD. We suggest that increased HRPF can be an effective treatment for respiratory diseases in adolescents, and health practitioners should pay more attention to helping adolescents with RD to gain or maintain high HRPF.

The deep mesa process for pixel isolation with ICP-RIE (Inductively Coupled Plasma – Reactive Ion Etching) was studied to develop InAs/GaSb type-Ⅱ superlattice (T2SL) LWIR photodetector with nBn structure. To reduce the lateral diffusion current component of the dark current components, it is essential to accomplish a proper deep dry etching process that can completely isolate absorption layer. In this work, ICP-RIE dry etching was studied to implement the smooth, vertical and isolated pixels. By increasing substrate temperature and adjusting the ratio of Ar in BCl3/Ar gas, it was found that the etch rate was largely increased and mesa shpae has become perpendicular and smooth. It was also found that dark current density was increased as the surface roughness increased. For the best sufrgace roughness, the dark current density of 15 μm pitch device fabricated exhibited 4.92x10-6 A/cm2 at and applied bias of -0.1 V and a temperature of 80 K.

High operating temperature(HOT) is the key for low size, weight and power(SWaP) detector development and SWaP detector is the key for modern weapon system such as unmanned aerial vehicle(UAV) and man portable system. The low dark current that determines the operating temperature can be achieved by adopting InAs/InAsSb type-II superlattice(T2SL) absorber and nBn structure. In this work, HOT mid-wavelength infrared(MWIR) detector with InAs/InAsSb T2SL absorber and AlAsSb barrier was developed. The AlAsSb barrier shows excellent lattice match with GaSb substrate. Only the dry etch for pixel reticulation was applied to fabricate the device. At 80 K, dark current density is 2e-9 A/cm2 at the bias -0.2 V and, at 130 K, 2e-7 A/cm2 at the bias -0.1 V. The quantum efficiency was measured for both front side illumination and back side illumination. The back side illumination offers higher quantum efficiency than the front side illumination. The average quantum efficiency is about 50 % for front side illumination with 3 μm absorber. The 640 x 512 VGA format focal plane array(FPA) with 15 μm pitch was fabricated to study the temperature dependency of electro-optical characteristics. It was found that mean noise equivalent temperature difference(NETD) below 150 K is 15 mK, which is limited by the well capacitance. As the temperature increases NETD increases proportional to the dark current.

This study examined the rate of injuries and chronic pain in collegiate water-ski athletes as a preliminary study. We also compared the mechanics and cause of injuries by the level of water-skiing experiences. A total number of 96 collegiate water-ski athletes, aged 21.4 ± 2.23 years, participated in the study. An off-line questionnaire was distributed at the collegiate tournaments in the United States. The questionnaire consisted of 20 questions, including demographic information, body region and type of injuries, mechanics and cause of injuries, chronic pain and pain management. A Chi-squared test was used to examine the differences in injury rates by sex and the level of experiences (beginner: &lt, 5 years, intermediate: 5–10 years, advanced: &lt, 10 years). The significance level was set at ≤0.05. A total of 336 water skiing-related injuries were observed from 96 participants. The ankle/feet, knee, and head/neck regions were the most common body regions injured, representing 26.5, 16.7, and 15.8%, respectively. Female athletes were more likely to have nerve injuries than male athletes (p = 0.039). The intermediate athletes were more likely to have trunk (p = 0.047) and upper extremity (p = 0.042) injuries than beginner athletes, and the beginner athletes had less joint/ligament (p = 0.001) and bone injury (p = 0.010) compared to the advanced athletes. Torsion/twisting (32.8%) and deceleration (26.9%) were the most common mechanism of injury. Beginner athletes experienced injuries more due to insufficient skill (p = 0.03), while the advanced athletes were likely to have more injuries by the loss of control (p = 0.01). Collegiate athletes had higher rates of chronic pain in the trunk (42.7%) and skeletal muscle (43.8%), and they participated in stretching/exercise (40.8%) and massage/form rolling (29.6%) to manage their chronic pain. The present study revealed that injury rates in males and females were 49.7% and 50.2%, respectively. Female athletes were more likely to have a nerve injury than male athletes. The mechanics and cause of injuries were different by the level of experiences where different training approaches may be required to minimize the injuries. Additionally, the strength and conditioning program that is systematically designed for core strength is needed to eliminate chronic trunk pain in collegiate water-skiing athletes.

Intraocular foreign bodies (IOFBs) are critical ophthalmic emergencies that require urgent diagnosis and treatment to prevent blindness or globe loss. This study aimed to examine the various clinical presentations of IOFBs, determine the prognostic factors for final visual outcomes, establish diagnostic protocols, and update treatment strategies for patients with IOFBs. We retrospectively reviewed patients with IOFBs between 2005 and 2019. The mean age of the patients was 46.7 years, and the most common mechanism of injury was hammering (32.7%). The most common location of IOFBs was the retina and choroid (57.7%), and the IOFBs were mainly metal (76.9%). Multivariate regression analysis showed that poor final visual outcomes (&lt, 20/200) were associated with posterior segment IOFBs (odds ratio (OR) = 11.556, p = 0.033) and retinal detachment (OR = 4.781, p = 0.034). Diagnosing a retained IOFB is essential for establishing the management of patients with ocular trauma. To identify IOFBs, ocular imaging modalities, including computed tomography or ultrasonography, should be considered. Different strategies should be employed during the surgical removal of IOFBs depending on the material, location, and size of the IOFB.

The purpose of the present cross-sectional study was to examine the impacts of allergic respiratory diseases on physical activity (PA), sedentary behaviors (SB), and body mass index (BMI) by matching age and gender with those adolescents without allergic respiratory diseases. This present study analyzed data from the 2019 Korea Youth Risk Behavior Web-based Survey (KYRBWS). Among 57,303 Korean adolescents who responded to the survey, the study divided adolescents into three different groups (i.e., general, asthma, and allergic rhinitis group). Asthma and allergic rhinitis groups included adolescents who checked on asthma- or allergic rhinitis-related questions as ‘yes’ (n = 259, n = 259), but the general group responded to any diseases-related question as ‘no’ (n = 259). The age and gender of participants among the three groups were matched. The results showed weight and BMI were significantly higher in asthma and allergic rhinitis groups compared to the general group (p &lt, 0.001, p &lt, 0.001). Furthermore, age, asthma, and allergic rhinitis were observed to be strong risk factors for predicting obesity in adolescents (BMI, &gt, 25.0 kg/m2). In addition, this study found allergic respiratory diseases strong impacts on BMI levels because adolescents with ongoing asthma, or allergic rhinitis symptoms were more likely to have the inevitability of further weight gain compared to the general adolescents. Therefore, not only national interest in adolescents with allergic respiratory disease is essential, but PA should be encouraged to prevent and alleviate these diseases due to obesity.