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Single-molecule experiments offer a unique means to probe molecular properties of individual molecules-yet they rest upon the successful control of background noise and irrelevant signals. In single-molecule transport studies, large amounts of data that probe a wide range of physical and chemical behaviors are often generated. However, due to the stochasticity of these experiments, a substantial fraction of the data may consist of blank traces where no molecular signal is evident. One-class (OC) classification is a machine learning technique to identify a specific class in a data set that potentially consists of a wide variety of classes. Here, we examine the utility of two different types of OC classification models on four diverse data sets from three different laboratories. Two of these data sets were measured at cryogenic temperatures and two at room temperature. By training the models solely on traces from a blank experiment, we demonstrate the efficacy of OC classification as a powerful and reliable method for filtering out blank traces from a molecular experiment in all four data sets. On a labeled 4,4'-bipyridine data set measured at 4.2 K, we achieve an accuracy of 96.9 ± 0.3 and an area under the receiver operating characteristic curve of 99.5 ± 0.3 as validated over a fivefold cross-validation. Given the wide range of physical and chemical properties that can be probed in single-molecule experiments, the successful application of OC classification to filter out blank traces is a major step forward in our ability to understand and manipulate molecular properties.
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BACKGROUND: Minimalistic footwear provides adequate toe space, tripod function, improving foot function, muscle activation and stability during walking similarly to barefoot walking. Due to the increasing popularity of this specific footwear, there is a lack of research focusing on general users of minimalistic footwear. RESEARCH QUESTION: Does annual walking in minimalistic footwear affect gait biomechanics? METHODS: Cross-sectional study involving twenty participants in a minimalistic footwear group with both experience (MFE) and no experience (NMFE). Participants walked in three different conditions (barefoot, minimalistic, and neutral footwear) in the laboratory at normal human walking speed. RESULTS: A significant main effect of groups regardless of footwear conditions show significantly greater values during walking in minimalistic footwear and barefoot in the stride length (p=0.035, p=0.003, respectively), and stride width (p=0.047, p=0.028, respectively) in the NMFE group compared to MFE group. The significant differences in the main effects of footwear regardless of experience were found in stance time (p<0.001), steps per minute (p<0.001), stride length (<0.001), foot adduction in TO (p<0.001), foot eversion angle in IC and TO (p<0.001, p<0.001, respectively), foot progression angle (p<0.001), ankle dorsiflexion angle in IC and TO (p<0.001, p<0.001, respectively), in ankle eversion angle in IC and TO (p<0.001, p<0.001, respectively), knee flexion angle in IC and TO (p<0.001; p<0.001, respectively), and in knee flexion range of motion (p<0.001). SIGNIFICANCE: Based on our findings, barefoot walking should be used primarily during daily activities if the environment is conducive. Only one year of experience with minimalistic footwear seems insufficient and an intervention should be incorporated to change the gait pattern when transitioning to full minimalistic footwear walking.
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The aim of this study was to examine the effect of attentional focus instructions on the biomechanical variables associated with the risk of anterior cruciate ligament injury of the knee joint during a drop landing task using a time series analysis. Ten female volleyball players (age: 20.4 ± 0.8 years, height: 169.7 ± 7.1 cm, mass: 57.6 ± 3.1 kg, experience: 6.3 ± 0.8 years) performed landings from a 50 cm height under three different attentional focus conditions: (1) external focus (focus on landing as soft as possible), (2) internal focus (focus on bending your knees when you land), and (3) control (no-focus instruction). Statistical parameter mapping in the sagittal plane during the crucial first 30% of landing time showed a significant effect of attentional focus instructions. Despite the similarity in landing performance across foci instructions, adopting an external focus instruction promoted reduced vertical ground reaction force and lower sagittal flexion moment during the first 30% of execution time compared to internal focus, suggesting reduced knee loading. Therefore, adopting an external focus of attention was suggested to reduce most biomechanical risk variables in the sagittal plane associated with anterior cruciate ligament injuries, compared to internal focus and control condition. No significant differences were found in the frontal and horizontal planes between the conditions during this crucial interval.
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Atenção , Articulação do Joelho , Voleibol , Humanos , Feminino , Voleibol/fisiologia , Fenômenos Biomecânicos/fisiologia , Articulação do Joelho/fisiologia , Adulto Jovem , Atenção/fisiologia , Lesões do Ligamento Cruzado Anterior/fisiopatologiaRESUMO
This study investigates the influence of the quality of the "deep squat" movement, adapted from the Functional Movement Screen (FMS) system, on the lower extremity movement pattern during baseball throwing, and its potential impact on throwing performance and propulsion efficiency. Twenty-two baseball players were recruited and categorized into two groups: 13 in the high-score squat group (HSS) and 9 in the low-score squat group (LSS), based on their deep squat screening results. This research explored disparities in ball velocity, propulsion efficiency, propulsion ground reaction force (GRF) characteristics, and throwing kinematics between these two groups. The findings revealed no significant difference in ball velocity between the groups. However, the LSS group demonstrated a lower propulsion GRF efficiency (p < 0.030, ES = 0.46), along with a higher vertical peak GRF (p < 0.002, ES = 0.66). In the pivot leg, the HSS group exhibited significantly lower impulse forces in the Impulse Fresultant (p < 0.035, ES = 0.45), throwing direction (p < 0.049, ES = 0.42), and vertical direction (p < 0.048, ES = 0.42). Additionally, the contribution to the ball velocity of the pivot leg was significantly greater in the HSS group, along with significantly better efficiency in Impulse Fresultant (p < 0.035, ES = 0.45), throwing direction (p < 0.053, ES = 0.41), and vertical direction (p < 0.032, ES = 0.46). In the leading leg, the HSS group demonstrated significantly lower impulse forces in the Impulse Fresultant (p < 0.001, ES = 0.69), throwing direction (p < 0.007, ES = 0.58), and vertical direction (p < 0.001, ES = 0.70). Moreover, the contribution to the ball velocity of the leading leg was significantly greater in the HSS group, accompanied by significantly better efficiency in Impulse Fresultant (p < 0.003, ES = 0.63), throwing direction (p < 0.005, ES = 0.60), and vertical direction (p < 0.021, ES = 0.49). In conclusion, this study suggests that squat screening is a valuable tool for assessing propulsion efficiency. Coaches and trainers should be mindful of players with low squat quality but high throwing performance, as they may face increased impact and injury risks in the future.
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Chemistry of the Au-S interface at the nanoscale is one of the most complex systems to study, as the nature and strength of the Au-S bond change under different experimental conditions. In this study, using mechanically controlled break junction technique, we probed the conductance and analyzed Flicker noise for several aliphatic and aromatic thiol derivatives and thioethers. We demonstrate that Flicker noise can be used to unambiguously differentiate between stronger chemisorption (Au-SR) and weaker physisorption (Au-SRR') type interactions. The Flicker noise measurements indicate that the gold rearrangement in chemisorbed Au-SR junctions resembles that of the Au rearrangement in pure Au-Au metal contact breaking, which is independent of the molecular backbone structure and the resulting conductance. In contrast, thioethers showed the formation of a weaker physisorbed Au-SRR' type bond, and the Flicker noise measurement indicates the changes in the Au-anchoring group interface but not the Au-Au rearrangement like that in the Au-SR case. Additionally, by employing single-molecular conductance and Flicker noise analysis, we have probed the interfacial electric field-catalyzed ring-opening reaction of cyclic thioether under mild environmental conditions, which otherwise requires harsh chemical conditions for cleavage of the C-S bond. All of our conductance measurements are complemented by NEGF transport calculations. This study illustrates that the single-molecule conductance, together with the Flicker noise measurements can be used to tune and monitor chemical reactions at the single-molecule level.
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PURPOSE: The purpose of this study was to determine whether regular running distance and biomechanics are related to medial central femur cartilage (MCFC) structure. METHODS: The cross-sectional study sample consisted of 1164 runners and nonrunners aged 18-65 yr. Participants completed questionnaires on physical activity and their running history. We performed quantitative magnetic resonance imaging of knee cartilage-T2 relaxation time (T2) mapping (high T2 indicates cartilage degeneration)-and a running biomechanical analysis using a three-dimensional motion capture system. A 14-d monitoring of the physical activity was conducted. RESULTS: Those aged 35-49 yr were at 84% higher odds of having MCFC T2 in the highest level (85th percentile, P < 0.05) compared with youngest adults indicating that MCFC structures may be altered with aging. Being male was associated with 34% lower odds of having T2 at the highest level ( P < 0.05) compared with females. Nonrunners and runners with the highest weekly running distance were more likely to have a high T2 compared with runners with running distance of 6-20 km·wk -1 ( P < 0.05). In addition, the maximal knee internal adduction moment was associated with a 19% lower odds of having T2 at the highest level ( P < 0.05). CONCLUSIONS: Females compared with males and a middle-aged cohort compared with the younger cohort seemed to be associated with the degeneration of MCFC structures. Runners who ran 6-20 km·wk -1 were associated with a higher quality of their MCFC compared with highly active individuals and nonrunners. Knee frontal plane biomechanics was related to MCFC structure indicating a possibility of modifying the medial knee collagen fibril network through regular running.
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Cartilagem Articular , Articulação do Joelho , Imageamento por Ressonância Magnética , Corrida , Humanos , Corrida/fisiologia , Masculino , Feminino , Estudos Transversais , Adulto , Articulação do Joelho/fisiologia , Articulação do Joelho/diagnóstico por imagem , Pessoa de Meia-Idade , Cartilagem Articular/fisiologia , Cartilagem Articular/anatomia & histologia , Cartilagem Articular/diagnóstico por imagem , Fenômenos Biomecânicos , Adulto Jovem , Adolescente , Idoso , Fatores Etários , Fatores Sexuais , Fêmur/fisiologia , Fêmur/anatomia & histologia , Fêmur/diagnóstico por imagemRESUMO
Injury prevention is essential in running due to the risk of overuse injury development. Tailoring running shoes to individual needs may be a promising strategy to reduce this risk. Novel manufacturing processes allow the production of individualised running shoes that incorporate features that meet individual biomechanical and experiential needs. However, specific ways to individualise footwear to reduce injury risk are poorly understood. Therefore, this scoping review provides an overview of (1) footwear design features that have the potential for individualisation; and (2) the literature on the differential responses to footwear design features between selected groups of individuals. These purposes focus exclusively on reducing the risk of overuse injuries. We included studies in the English language on adults that analysed: (1) potential interaction effects between footwear design features and subgroups of runners or covariates (e.g., age, sex) for running-related biomechanical risk factors or injury incidences; (2) footwear comfort perception for a systematically modified footwear design feature. Most of the included articles (n = 107) analysed male runners. Female runners may be more susceptible to footwear-induced changes and overuse injury development; future research should target more heterogonous sampling. Several footwear design features (e.g., midsole characteristics, upper, outsole profile) show potential for individualisation. However, the literature addressing individualised footwear solutions and the potential to reduce biomechanical risk factors is limited. Future studies should leverage more extensive data collections considering relevant covariates and subgroups while systematically modifying isolated footwear design features to inform footwear individualisation.
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The main purpose of this study was to investigate the relationship among Achilles tendon (AT) dimensions, ankle joint stiffness, and footfall patterns in recreational rearfoot and non-rearfoot runners. Based on the foot strike index, a total of 107 runners were divided into rearfoot (47 females/40 males) and non-rearfoot runners (14 females/6 males). All participants had theirs AT dimensions (AT length, AT thickness, and AT moment arm) measured using a combination of ultrasound and motion capture systems. In addition, all performed running trials measured at self-selected speed in laboratory-neutral shoes. A partial correlation coefficient was used for correlations between the selected variables. The results revealed a significant relationship between ankle joint stiffness and level of footfall pattern in rearfoot (r = 0.232, p = 0.032) and non-rearfoot runners (r = -0.811, p < 0.001). The results also suggest a relationship between AT thickness and foot strike index (r = -0.486) in non-rearfoot runners. Runners whose footfall pattern is closer to the heel have greater ankle joint stiffness. Non-rearfoot runners whose footfall pattern is closer to the toe have a thinner AT. Non-rearfoot runners with thicker AT had greater ankle joint stiffness.
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Tendão do Calcâneo , Masculino , Feminino , Humanos , Tendão do Calcâneo/diagnóstico por imagem , Tornozelo , Fenômenos Biomecânicos , Pé , Extremidade InferiorRESUMO
There are relatively few running studies that have attempted to prospectively identify biomechanical risk factors associated with Achilles tendon (AT) injuries. Therefore, the aim was to prospectively determine potential running biomechanical risk factors associated with the development of AT injuries in recreational, healthy runners. At study entry, 108 participants completed a set of questionnaires. They underwent an analysis of their running biomechanics at self-selected running speed. The incidence of AT running-related injuries (RRI) was assessed after 1-year using a weekly questionnaire standardized for RRI. Potential biomechanical risk factors for the development of AT RRI injury were identified using multivariable logistic regression. Of the 103 participants, 25% of the sample (15 males and 11 females) reported an AT RRI on the right lower limb during the 1-year evaluation period. A more flexed knee at initial contact (odds ratio = 1.146, P = .034) and at the midstance phase (odds ratio = 1.143, P = .037) were significant predictors for developing AT RRI. The results suggested that a 1-degree increase in knee flexion at initial contact and midstance was associated with a 15% increase in the risk of an AT RRI, thus causing a limitation of training or a stoppage of running in runners.
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Tendão do Calcâneo , Traumatismos do Tornozelo , Corrida , Masculino , Feminino , Humanos , Estudos Prospectivos , Extremidade Inferior , Joelho , Corrida/lesões , Fenômenos BiomecânicosRESUMO
This study investigated the short-term responses of step characteristics in sprinters and team-sports players under different bend conditions. Eight participants from each group completed 80 m sprints in four conditions: banked and flat, in lanes two and four (L2B, L4B, L2F, L4F). Groups showed similar changes in step velocity (SV) across conditions and limbs. However, sprinters produced significantly shorter ground contact times (GCT) than team sports players in L2B and L4B for both left (0.123 s vs 0.145 s and 0.123 s vs 0.140 s) and right steps (0.115 s vs 0.136 s and 0.120 s vs 0.141 s) (p > 0.001-0.029; ES = 1.15-1.37). Across both groups, SV was generally lower in flat conditions compared to banked (Left: 7.21 m/s vs 6.82 m/s and Right: 7.31 m/s vs 7.09 m/s in lane two), occurring due to reduced step length (SL) rather than step frequency (SF), suggesting that banking improves SV via increased SL. Sprinters produced significantly shorter GCT in banked conditions that led to non-significant increases in SF and SV, highlighting the importance of bend sprinting specific conditioning and training environments representative of indoor competition for sprint athletes.
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Desempenho Atlético , Corrida , Humanos , Corrida/fisiologia , Esportes de Equipe , Rádio (Anatomia) , Fenômenos Biomecânicos , Extremidade Superior , Desempenho Atlético/fisiologiaRESUMO
Although prevention is better than treatment, after a knee injury occurs, the adjustment of the movement technique back to the posture before the injury and the restoration of accuracy is very important for professional and amateur players. This study aimed to compare the differences in lower limb mechanics during the golf downswing between those with and without a history of knee joint injury. A total of 20 professional golfers with single-digit handicaps were recruited for this study, 10 of whom had a knee injury history (KIH+), while another 10 players were without a knee injury history (KIH-). From the 3D analysis, selected kinematic and kinetic parameters during the downswing were analyzed using an independent samples t-test with a significance level of α = 0.05. During the downswing, individuals with KIH+ exhibited a smaller hip flexion angle, smaller ankle abduction angle, and larger ankle adduction/abduction range of motion (ROM). Moreover, there was no significant difference found in the knee joint moment. Athletes with a history of knee injury can adjust the motion angles of their hip and ankle joints (e.g., by avoiding excessive forward leaning of the trunk and maintaining stable foot posture without inward or outward rotation) to minimize the impact of changes in their movement patterns resulting from the injury.
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This study aims to explore the variation of lower extremity kinematic characteristics when elite taekwondo athletes perform the side-kick on protective gear placed at various heights. Twenty distinguished male national athletes were recruited and were asked to kick targets at three different heights adjusted according to their body height. A three-dimensional (3D) motion capture system was used to collect kinematic data. Kinematic parameters differences in the side-kick at three different heights were analyzed by using a one-way ANOVA (p < .05). The results revealed significant differences in the peak linear velocities of the pelvis, hip, knee, ankle, and centre of gravity of the foot during the leg-lifting phase (p < .05). Significant differences between heights were noted in the maximum angle of pelvis left tilting and hip abduction in both phases. In addition, the maximum angular velocities of pelvis left tilting and hip internal rotation were only different in the leg-lifting phase. This study found that, to kick at a higher target, athletes increase the linear velocities of their pelvis and all lower extremity joints of attacking leg in the leg-lifting phase; however, they only increase rotational variables on the proximal segment at the peak angle of the pelvis (left tilting) and hip (abduction and internal rotation) in the same phase. As an application in actual competitions, according to the opponent's body height, athletes can adjust both linear and rotational velocities of their proximal segements (pelvis and hip) and deliver into distal segements (knee, ankle, foot) linear velocity to perform accurate and rapid kicks.
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Perna (Membro) , Extremidade Inferior , Masculino , Humanos , Fenômenos Biomecânicos , Joelho , PéRESUMO
Achilles tendinopathy was reported to have the highest incidence proportion of all running-related injuries. The purpose of this study was to analyse the association between the Achilles tendon structure and running activity status. 350 healthy participants (runners and inactive controls, 30-50 years) participated in this research. Each participant completed questionnaires: socioeconomic, psychological, physical activity habits, running status and history and VISA-A. Magnetic resonance imaging, anthropological, running biomechanics and 14 days of physical activity monitoring assessments were performed. There was a higher odd of being in the upper quartile of the Achilles tendon T2* relaxation time with higher maximal knee extension moment independent of age and sex. Compared with runners who ran 21-40 km per week, non-runners and those who ran more than 40 km per week had increased odds of having longest the Achilles tendon T2* relaxation time. Regular running of 21 to 40 km per week is related to the Achilles tendon T2* relaxation time indicating possibly better water content and collagen orientation in these runners with compare to inactive non-runners or highly active individuals. In addition, Achilles tendon T2* relaxation time as indirect indicator of the Achilles tendon structure was positively related to the maximal knee extension moment during running.
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Tendão do Calcâneo , Corrida , Tendinopatia , Humanos , Tendão do Calcâneo/diagnóstico por imagem , Tendão do Calcâneo/lesões , Fenômenos Biomecânicos , Corrida/lesões , Articulação do JoelhoRESUMO
We report on the single-molecule electronic and thermoelectric properties of strategically chosen anthracene-based molecules with anchor groups capable of binding to noble metal substrates, such as gold and platinum. Specifically, we study the effect of different anchor groups, as well as quantum interference, on the electric conductance and the thermopower of gold/single-molecule/gold junctions and generally find good agreement between theory and experiments. All molecular junctions display transport characteristics consistent with coherent transport and a Fermi alignment approximately in the middle of the highest occupied molecular orbital/lowest unoccupied molecular orbital gap. Single-molecule results are in agreement with previously reported thin-film data, further supporting the notion that molecular design considerations may be translated from the single- to many-molecule devices. For combinations of anchor groups where one binds significantly more strongly to the electrodes than the other, the stronger anchor group appears to dominate the thermoelectric behavior of the molecular junction. For other combinations, the choice of electrode material can determine the sign and magnitude of the thermopower. This finding has important implications for the design of thermoelectric generator devices, where both n- and p-type conductors are required for thermoelectric current generation.
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The aim of this study was to assess acute effects of footwear conditions (barefoot, minimalist and standard running shoes) on running impact loading in the preschool years. Fourty-eight habitually shod preschool children (26 males and 22 females) were divided into four age groups (3-, 4-, 5- and 6-year-old). Children performed a simple running game in three different conditions. Three-dimensional biomechanical analysis was carried out during overground running. Statistical parametric mapping was performed on the vertical ground reaction force profiles during the stance phase and one-way repeated measures ANOVA on the vertical instantaneous loading rate. Three-year-old children displayed significantly lower vertical ground reaction force values in the barefoot condition compared to minimalist (3-7% stance) and standard running shoes (7-11% stance). There were also differences in vertical instantaneous loading rate, where 3-year-olds had lower loading when barefoot than in minimalist (p = 0.010, d = 1.19) or running shoes (p = 0.045, d = 0.98), despite no differences in the footstrike pattern (mostly rearfoot-midfoot strike). No differences were found for the older children. Running in minimalist shoes did not imitate barefoot running in 3-year-old children. On the contrary, increased loading was observed in minimalist shoes in early running developmental stages.
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Marcha , Corrida , Masculino , Feminino , Humanos , Pré-Escolar , Criança , Adolescente , Fenômenos Biomecânicos , Pé , SapatosRESUMO
Patellofemoral pain (PFP) is a common musculoskeletal pain disorder experienced by runners. While biomechanics of those with PFP have been extensively studied, methodological considerations may omit important adaptations exhibited by those experiencing and recovered from pain. Instead of a priori selection of discrete biomechanical variables, a data mining approach was leveraged to account for the high dimensionality of running gait data. Biomechanical data of runners symptomatic for, recovered from, and who had never experienced PFP were collected at the 1st (M1) and 21st (M21) minutes of a treadmill run. Principal component analysis and a logistic regression model were used to classify healthy and symptomatic runners, and a feature ranking process determined the important features. The M1 model achieved an accuracy of 82.76% with features related to knee flexion angle, hip abduction moment and gluteus maximus activation, while the M21 model required an additional nine features to achieve an accuracy of 79.31%. Data for recovered runners were projected onto the models, resulting in five and seven out of twelve symptomatic classifications at M1 and M21, respectively. Following the onset of pain, a greater number of features were required to classify runners with PFP, suggesting they may experience individual pain adaptation strategies.
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Síndrome da Dor Patelofemoral , Corrida , Humanos , Fenômenos Biomecânicos , Corrida/fisiologia , Marcha/fisiologia , Dor , Articulação do Joelho/fisiologiaRESUMO
The purpose of this study was to determine how the intrinsic head-trunk coordination dynamics that exist during forward running are modified during a dynamic sidestepping task. Fourteen athletes performed both forward running and sidestepping tasks. Head-trunk coordination and range of motion were assessed during the flight and stance phases in the transverse and sagittal planes. The sidestepping task resulted in greater in-phase head-trunk coordination during stance in the transverse plane (p < .001, ES = -1.71) and in reduced anti-phase coordination between head and trunk in the sagittal plane (p < .001, ES = 1.52). Statistical non-parametric mapping revealed that during sidestepping the sagittal plane coupling angle shifted away from anti-phase earlier during midstance. The sidestepping task resulted in greater transverse and sagittal plane head and trunk range of motion and greater vertical trunk centre of mass displacement. Sidestepping modified the intrinsic coordination dynamics that are present during forward running, with greater transverse plane head contributions and reductions in compensatory sagittal plane head motion, which may occur during the transition from weight acceptance to propulsion during the stance phase. These changes in the intrinsic coordination dynamics of the upper body during sidestepping tasks may impact visual perception and readiness compared to forward running during complex sports tasks.
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The roundhouse kick is one of the most widely applied techniques in a taekwondo competition. Because the scoring system of taekwondo has been changed, the skill of roundhouse kick has been affected. Therefore, coaches and athletes are attempting to better understand how to control the movement of the kick to gain points more effectively. The aim of this study was to investigate the differences in the biomechanical characteristics between the roundhouse kicks with higher and lower impact magnitude using an electronic body protector. Eighteen elite college Taekwondo athletes participated in this study. A motion capture system measured the kinematics data of the kicking leg. The results indicated that elite athletes can obtain a high-impact index of the electrical body protector through increasing the peak linear velocity of shank, even with the same foot velocity level. In regard to kinetic skills, the roundhouse kicks a high impact. The velocity of proximal kicking limb could predominantly contribute to the powerful roundhouse kicks to achieve the high-impact force for electrical body protector. Moreover, when the kick cannot be effectively scored during the game, coaches and masters should consider adjusting to increase the velocity of proximal kicking.
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Necessary for effective ambulation, head stability affords optimal conditions for the perception of visual information during dynamic tasks. This maintenance of head-in-space equilibrium is achieved, in part, by the attenuation of the high frequency impact shock resulting from ground contact. While a great deal of experimentation has been done on the matter during steady state locomotion, little is known about how locomotor asymmetry might affect head stability or dynamic visual acuity. In this study, fifteen participants walked on a split-belt treadmill while verbally reporting the orientation of a randomized Landolt-C optotype that was projected at heel strike. Participants were exposed to baseline, adaptation, and washout conditions, as characterized by belt speed ratios of 1:1, 1:3, and 1:1, respectively. Step length asymmetry, shock attenuation, high and low frequency head signal power, and dynamic visual acuity were averaged across the first and last fifty strides of each condition. Across the first fifty strides, step length asymmetry was significantly greater during adaptation than during baseline (p < 0.001; d = 2.442), and shock attenuation was significantly lower during adaptation than during baseline (p = 0.041; d = -0.679). High frequency head signal power was significantly greater during adaptation than during baseline (p < 0.001; d = -1.227), indicating a reduction in head stability. While dynamic visual acuity was not significantly lower during adaptation than during baseline (p = 0.052), a moderate effect size suggests a decrease in the measure between the two conditions (d = 0.653). Across the last fifty strides, many of the decrements observed between the baseline and adaptation conditions were greatly reduced. The results of this study indicate that the locomotor asymmetry imposed by the split-belt treadmill during early adaptation might lead to moderate decrements in shock attenuation, head stability, and dynamic visual acuity. Moreover, the relative reduction in magnitude of these decrements across the last fifty strides underscores the adaptive nature of the locomotor and visuomotor systems.
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Teste de Esforço , Caminhada , Adaptação Fisiológica , Marcha , Calcanhar , Humanos , LocomoçãoRESUMO
Dialkynylferrocenes exhibit attractive electronic and rotational features that make them ideal candidates for use in molecular electronic applications. However previous works have primarily focussed on single-molecule studies, with limited opportunities to translate these features into devices. In this report, we utilise a variety of techniques to examine both the geometric and electronic structure of a range of 1,1'-dialkynylferrocene molecules, as either single-molecules, or as self-assembled monolayers. Previous single molecule studies have shown that similar molecules can adopt an 'open' conformation. However, in this work, DFT calculations, STM-BJ experiments and AFM imaging reveal that these molecules prefer to occupy a 'hairpin' conformation, where both alkynes point towards the metal surface. Interestingly we find that only one of the terminal anchor groups binds to the surface, though both the presence and nature of the second alkyne affect the thermoelectric properties of these systems. First, the secondary alkyne acts to affect the position of the frontier molecular orbitals, leading to increases in the Seebeck coefficient. Secondly, theoretical calculations suggested that rotating the secondary alkyne away from the surface acts to modulate thermoelectric properties. This work represents the first of its kind to examine the assembly of dialkynylferrocenes, providing valuable information about both their structure and electronic properties, as well as unveiling new ways in which both of these properties can be controlled.