Search Results (25)

With ongoing technological advancements, artificial tactile systems have become a prominent area of research, aiming to replicate human tactile capabilities and enabling machines and devices to interact with their environments. Achieving effective artificial tactile sensing relies on the integration of high-performance pressure sensors, precise signal acquisition, robust transmission, and rapid data processing. In this study, we developed a sensor array system based on flexible pressure sensors designed to recognize objects of varying shapes and sizes. The system comprises a multi-channel acquisition circuit and a signal transmission circuit and employs a convolutional neural network (CNN) to classify distinct signal patterns. In a test on an individual, the test results demonstrate that the system achieves a high recognition accuracy of 99.60% across two sphere sizes, three cylinder sizes, a cone, and a rectangular prism. In a group of eight people, it can achieve a recognition accuracy of 93.75%. Furthermore, we applied this sensor array system in an experimental setting involving a ball-throwing action, and it effectively recognized four distinct stages: empty hand, holding the ball, throwing, and catching. In repeated tests by other individuals, it was also able to clearly distinguish each stage. The development of artificial tactile systems allows robots to engage with their environments in a more nuanced and precise manner, enabling complex tasks such as surgical procedures, enhancing the interactive experience of wearable devices, and increasing immersion in virtual reality (VR) and augmented reality (AR). When integrated with deep learning, artificial tactile sensing shows significant potential for creating more intelligent and efficient applications. Full article

The motion control of the virtual avatar enhances a sense of embodiment in a virtual reality (VR). Yet, the detailed relationship between motion control, assigned tasks, and the sense of embodiment remains unclear. We aim to investigate the relationships between degrees of control on a full-body avatar and three elements of the sense of embodiment: the sense of self-location, agency, and ownership in standalone and interaction tasks. To do this, we conducted a user study with three conditions of control over a full-body avatar. The types of control are (1) Low—control of an upper-body avatar, (2) Mid—control of a full-body avatar from three sensors, and (3) High—control of a full-body avatar from six sensors. These three control methods, which were used to animate the avatars and imitate the users’ pose, differ in accuracy and stability. Participants embodied three kinds of control and performed a single-user task (obstacle avoidance) and a multi-user task (catch-ball). Our results indicate that the degree of control impacts participants’ embodiment. However, there was no significant difference between high- and mid-control in the multi-user task, which was a different result from the single-user task. This suggests for virtual bodies that the participants capacity to control and see are the same or different, which may affect embodiment. Our result also shows that the multi-user task enhanced the sense of embodiment compared to the single-user task in the low- and mid-control avatars. Yet, the multi-user task decreased the sense of agency of the high-control avatar. This suggests that a failure of the assigned task may affect the sense of agency, especially when it is close to success, yielding revulsion. We further elucidate the insights into the relationship between the degree of control, the assigned tasks, and the elements of a sense of embodiment. Full article

Background/Objectives: Eye–foot coordination is essential in sports and daily life, enabling the synchronization of vision and movement for tasks like ball control or crossing obstacles. This study aimed to examine both the validity and reliability of an innovative eye–foot coordination (EFC) test in a dual-task paradigm in children aged 6–11 years and the capacity of this test to discriminate between sex and age. Methods: A total of 440 schoolchildren aged 6–11 years participated in this cross-sectional study. A ball control test, involving kicking and catching, was used to assess EFC. The assessment included three conditions: without interference (WI), with auditory interference (AI), and with visual interference (VI). Results: The ICCs per the EFC test scores were 0.975 for foot successes (95% CI = 0.961–0.983; p < 0.001) and 0.747 for foot mistakes (95% CI = 0.611–0.835; p < 0.001). The SEM for the standing successes was 3.082 (10.81%), and the MDC was 4.860 (17.05%). For the standing mistakes, the SEM was 1.551 (19.33%) and the MDC was 3.452 (43.04%). Moreover, boys had a significantly higher number of successes in the WI, AI, and VI conditions (p < 0.001, respectively) than girls, although girls had more mistakes than boys only in the VI condition (p = 0.025). Conclusions: The EFC test showed adequate reliability and validity. Also, the EFC test showed that performance worsened with interference regardless of sex and age, especially in girls in the VI condition. Full article

Background: Malnutrition has extensive consequences, affecting multiple levels of functioning, including motor skill impairments. However, current interventions have mainly focused on dietary treatment, often neglecting motor impairments and relying solely on clinical and anthropometric indicators to assess treatment response. This study aims to bridge this gap by examining the combined effect of ready-to-use supplementary food (RUSF) and high-intensity motor learning (HiML) on motor skill-related physical fitness in children with moderate thinness (MT). Methods: A cluster randomized controlled trial was conducted among children 5–7 years old with MT in Jimma Town. Three schools were randomized to three intervention arms, including a total of 69 children: RUSF (n = 23), RUSF + HiML (n = 25), and no intervention (n = 21). The HiML training was applied for 12 weeks, and RUSF was distributed daily for 12 weeks. HiML was given daily (1 h/day, 5 days/week). The primary outcome was motor skill-related physical fitness assessed at baseline and endline using the performance and fitness test battery (PERF-FIT). The changes from baseline to endline measurements were calculated as differences, and the mean difference in these changes/differences (DID) was then computed as the outcome measure. AN(C)OVA was used to directly investigate differences between groups. Statistical significance was declared at p-value ≤ 0.05. Results: There was a significantly greater and comparable improvement in both the RUSF and RUSF + HiML groups compared to the control group for the ‘stepping’ item (p < 0.001), the ‘side jump’ item (p < 0.001), the ‘standing long jump’ (p < 0.001) and the ‘jumping and hopping’ total (p = 0.005). The RUSF + HiML group showed significantly greater improvements in the ‘bounce and catch’ (p = 0.001) and ‘throw and catch’ (p < 0.001) items compared to the RUSF group, which, in turn, demonstrated greater improvement than the control group in both items (p < 0.01). Conclusions: A 12-week combination of RUSF + HiML was proven to be safe in children with MT and caused clear improvements in motor skill-related physical fitness. When the children received RUSF with HiML training, similar gains in stepping, side jump, standing long jump, and jumping and hopping were observed, except for the ball skills where the HiML training group performed better. Full article

This paper addresses the challenge of assessing relatedness and functional interdependence through connecting passes within invasion games, which may offer valuable pedagogical insights into gameplay for accessibility and inclusiveness. Hence, the purpose of this paper is twofold. Firstly, it presents preliminary work on the methodology for computing open passing lanes and derived metrics, integrating spatiotemporal data analysis with event data. Secondly, using a within-subject design, it investigates how modified handball games influence game play opportunities. Data were collected during handball matches in a pre-teens Physical Education (PE) class with mixed-skill-level teams. Game actions (e.g., passes, receptions, and shots) were manually recorded through systematic observation of video footage, while players’ positional data were captured with ultra-wideband technology. Findings provide evidence that employing a numerical advantage (one player up) enhances overall opportunities for individual attacking actions (i.e., more passing, catching actions, and goal-scoring opportunities) and relational actions (i.e., more open passing lanes) compared to equal numbers. Conversely, equal numbers with individual marking appeared more challenging, as fewer secure passing lanes were observed, and the ball possessor spent more time with the ball before releasing it. The developed approach holds promise for studying designed games to enhance inclusion and learning opportunities for all. Full article

The present study aimed to examine precision and variability in dart throwing performance and the relationships between these outcomes and bouncing, throwing and catching tasks in children with and without DCD. Children between the ages of 8 and 10 years (n = 165) were classified according to results obtained on the Movement Assessment Battery for Children (MABC-2) and divided into three groups: 65 children with severe DCD (s-DCD), 45 with moderate DCD (m-DCD) and 55 typically developing children (TD). All children performed the dart throwing test and the ball skill items of the Performance and Fitness Test (PERF-FIT). The accuracy and variability of dart throwing tasks were significantly different between TD and s-DCD (p < 0.01), and also between m-DCD and s-DCD (p < 0.01). Participants with s-DCD were also found to perform significantly worse on all PERF-FIT ball skill items than m-DCD (p < 0.001), and m-DCD were significantly poorer than TD (p < 0.001). The dart score and coefficient of variation of the long-distance task appear to be significant predictors for the ball skills and explain between 24 to 29% of their variance. In conclusion, poor results in aiming tasks using darts in children with DCD corroborate with the explanation of deficits in predictive control since the tasks require ballistic movements. Full article

Visual motion information plays an important role in the control of movements in sports. Skilled ball players are thought to acquire accurate visual information by using an effective visual search strategy with eye and head movements. However, differences in catching ability and gaze movements due to sports experience and expertise have not been clarified. Therefore, the purpose of this study was to determine the characteristics of gaze strategies based on eye and head movements during a ball-catching task in athlete and novice groups. Participants were softball and tennis players and college students who were not experienced in ball sports (novice). They performed a one-handed catching task using a tennis ball-shooting machine, which was placed at 9 m in front of the participants, and two conditions were set depending on the height of the ball trajectory (high and low conditions). Their head and eye velocities were detected using a gyroscope and electrooculography (EOG) during the task. Our results showed that the upward head velocity and the downward eye velocity were lower in the softball group than in the tennis and novice groups. When the head was pitched upward, the downward eye velocity was induced from the vestibulo-ocular reflex (VOR) during ball catching. Therefore, it is suggested that skilled ball players have relatively stable head and eye movements, which may lead to an effective gaze strategy. An advantage of the stationary gaze in the softball group could be to acquire visual information about the surroundings other than the ball. Full article

The aim of this study was to assess and compare performance and movement variability (MV) in both bilateral and unilateral vertical drop jumps (DVJs) under conditions involving the incorporation or exclusion of ball catching. Twelve amateur basketball players were recruited for participation in the study (seven females and five males). Participants performed three jumps in each of the six conditions analyzed in randomized order: bilateral DVJ without (BNB) and with ball (BB); unilateral DVJ right leg without (RNB) and with ball (RB); and unilateral DVJ left leg without (LNB) and with ball (LB). MV and DVJ performance parameters were analyzed with an accelerometer and a force platform. MV was quantified using the sample entropy (sample entropy; SampEn) derived from the acceleration of the lower back. Differences between the different DVJ conditions were determined with the Wilcoxon test, with a significance level set at p < 0.05. The comparisons were also assessed via standardized mean differences (Cohen’s d). No significant differences were observed in jump height, contact time and reactive strength index between conditions. However, the RB condition reported higher MV compared to RNB (effect size = 0.79; p = 0.016). Similarly, LNB showed greater MV compared to RNB (effect size = −0.62; p = 0.042). The inclusion of the ball in the DVJ increased the MV in the bilateral condition and in the right leg, but not in the unilateral condition with the left leg. The asymmetry between legs (right vs. left) in MV values in NOBALL conditions was higher (≈15%) compared to the BALL condition (≈5%). Full article

This study characterizes the effects of a postural training program on balance and muscle control strategies in a virtual reality (VR) environment. The Robotic Upright Stand Trainer (RobUST), which applies perturbative forces on the trunk and assistive forces on the pelvis, was used to deliver perturbation-based balance training (PBT) in a sample of 10 healthy participants. The VR task consisted of catching, aiming, and throwing a ball at a target. All participants received trunk perturbations during the VR task with forces tailored to the participant’s maximum tolerance. A subgroup of these participants additionally received assistive forces at the pelvis during training. Postural kinematics were calculated before and after RobUST training, including (i) maximum perturbation force tolerated, (ii) center of pressure (COP) and pelvic excursions, (iii) postural muscle activations (EMG), and (iv) postural control strategies (the ankle and hip strategies). We observed an improvement in the maximum perturbation force and postural stability area in both groups and decreases in muscle activity. The behavior of the two groups differed for perturbations in the posterior direction where the unassisted group moved towards greater use of the hip strategy. In addition, the assisted group changed towards a lower margin of stability and higher pelvic excursion. We show that training with force assistance leads to a reactive balance strategy that permits pelvic excursion but that is efficient at restoring balance from displaced positions while training without assistance leads to reactive balance strategies that restrain pelvic excursion. Patient populations can benefit from a platform that encourages greater use of their range of motion. Full article

This study aimed to evaluate the reliability of a manipulative eye–segmental (hand and foot) coordination task, namely the Wall Drop Punt Kick and Catch test (WDPK&C), over two weeks. Forty-one children and adolescents (18 boys, 23 girls) with a mean age of 10.2 (SD = 1.62) years old were recruited for assessment. Subjects had 30 s to perform as many ball impacts as possible on a wall two meters away, following a drop punt kick, rebound on the wall, and catch sequence. The Intraclass Correlation Coefficient (ICC = 0.896) for unique measures, Cronbach Alpha (α = 0.945), and Lin’s Concordance Correlation Coefficient (CCC = 0.896) provide evidence of reliability considering two consecutive measurements. These results further support the reliability of the WDPK&C test in a sample of Portuguese children and adolescents. Thus, the WDPK&C test can be applied to Portuguese boy and girl children and adolescents. Forthcoming studies should test the reliability of this test across different age groups since it is intended to be a test with a wide lifespan coverage. Full article

Codends are the posterior components of trawl nets that collect the catch and play a crucial role in the selectivity process. Due to the accumulation of catch and the variety of catch types, the quality of catch and trawl selectivity can be negatively impacted. Therefore, this study aims to investigate the effects of various catch configurations on the hydrodynamic characteristics, geometrical profile, and fluttering motions of the codend in a flume tank. A codend structure was designed and tested using various catch configurations, including grooved-type configurations (canvas, green canvas, basketballs) and spherical configurations (table tennis balls filled with water, balloons filled with water, and balls made of twine) in the flume tank. The sea trial data were compared with the flume tank data. The results indicate that there were no significant differences in the codend profiles between the different catch configurations. The drag of the codend with a grooved-type configuration was 13.63% greater than that obtained using a spherical configuration as the catch. The wavelet coefficient obtained from the codend drag revealed that the oscillations of the codend with a grooved-type catch configuration began at a periodicity of 0.07 s and were more intense than that of the codend with the spherical catch configuration. Moreover, these amplitudes increased as the codend flow velocity increased. The wavelet analysis results showed that the dominant frequency of the periodic high-energy coherent structures for the codend drag and codend displacements was detected at a low-frequency. In terms of displacement oscillation characteristics, the table tennis ball filled with water was an approximate substitute for real catch during the sea trial because the difference in wavelet coefficients for the codend displacements in amplitude and the period between the model codend with the table tennis ball filled with water and the full-scale codend was 91% and 89%, respectively. The findings of this study confirm the feasibility of replacing real catch with simulated catch configurations with similar shapes in model testing. They can provide basic scientific data for improving the hydrodynamic characteristics and selectivity of the codend structure. Full article

Physical performance is an essential factor for becoming a top elite team handball player; however, the relationship between specific and general physical performance is not well known. Consequently, the aim of the study was (1) to analyze the relationship between specific game-based and general physical performance in young elite male team handball players, and (2) to reduce the number of tests for a more practical implementation of physical performance diagnostics in team handball. Twenty young adult elite male team handball field players (18.6 ± 2.1 years) performed the team handball game-based performance test (GBPT), including specific movements in offense and defense such as catching, passing and throwing a ball, sprinting, stops, changes in direction, jumping, checking and screening, as well as general tests, including a 20 m sprinting test, a repeated sprint ability test (RSA), a modified t-test, countermovement (CMJ), squat (SJ) and drop jump test (DJ), a standing long jump test, a single-leg lateral three jumps test, a standing throw test, and the determination of the one repetition maximum (1RM) in the bench press, bench pull, front squat, and deadlift. Significant correlations were mostly found between different sprinting and jumping tests as well as between different strength tests. The principal component factor analysis revealed four components (power and speed, strength, jump shot performance, and endurance) including 21 variables of high loads (>0.60 or <−0.60). Due to the correlations between the different tests, we suggest a more practicable testing procedure including the 20 m sprinting test, CMJ test, 1RM in the bench press and front squat, as well as the GBPT for elite teams, or the t-test and the YoYo intermittent recovery test for youth and non-elite teams. Despite some correlations between specific and general tests, we suggest using the GBPT to measure specific performance in team handball. Full article

The purpose of this study was to develop a reactive agility test with soccer goalkeeper (GK)-specific movements (G-RAT) and to examine the reliability and validity of college-aged GKs. We designed a five-branch star-shaped course with diving and ball-catching movements under reactive conditions. In the setup, a start–goal line was set on the top of a branch and 3.5 m away from the center of the star-shaped setting. Content validity was assessed by six experts, and the item-content validity index (I-CVI) was calculated. Thirty-three male GKs performed the test trial twice. One test trial of G-RAT consists of three shuttles from the start–goal line to diving and ball-catching. For the reactive condition, GKs were instructed on which ball directions should dive when their body trunk reached 1.5 m away from the start–goal line. GKs were classified into regular (R) or non-regular (NR) groups. The intraclass correlation coefficient (ICC) and the receiver operating characteristic (ROC) curve analyses were used to assess the reliability and predictive power as convergent validity. The I-CVI was 0.83, which was greater than the acceptable level of 0.78. The ICC value was 0.94 (p < 0.01; 95% confidence interval (95%CI), 0.88–0.97). The GKs completed the test 14.3 ± 0.7 and 15.3 ± 1.0 s in the R and NR group (p < 0.01; Cohen’s d = 0.89), respectively. The area under the curves of G-RAT was 0.80 (95%CI, 0.64–0.96). These results show that a GK-specific agility test under reactive conditions would have sufficient reliability and both content and convergent validity in college-aged GKs. Full article

The assessment of motor proficiency is essential across childhood to identify children’s strengths and difficulties and to provide adequate instruction and opportunities; assessment is a powerful tool to promote children’s development. This study aimed to investigate the hierarchal order of the Test of Gross Motor Development-Third Edition (TGMD-3) items regarding difficulty levels and the differential item functioning across gender and age group (3 to 5, 6 to 8, and 9 to 10 years old). Participants are 989 children (3 to 10.9 years; girls n = 491) who were assessed using TGMD-3. For locomotor skills, appropriate results reliability (alpha = 1.0), infit (M = 0.99; SD = 0.17), outfit (M = 1.18; SD = 0.64), and point-biserial correlations (rpb values from 0.14 to 0.58) were found; the trend was similar for ball skills: reliability (alpha = 1.0), infit (M = 0.99; SD = 0.13), outfit (M = 1.08; SD = 0.52); point-biserial correlations (rpb values from 0.06 to 0.59) were obtained. Two motor criteria: gallop, item-1, and one-hand forehand strike, item-4, were the most difficult items; in contrast, run, item-2, and two-hand catch, item-2, were the easiest items. Differential item functioning for age was observed in nine locomotor and ten ball skills items. These items were easier for older children compared to younger ones. The TGMD-3 has items with different difficulty levels capable of differential functioning across age groups. Full article

The corannulene pincer (also known in the literature as the buckycatcher) is a fascinating system that may encapsulate, among other molecules, the $C_{60}$ and $C_{70}$ fullerenes. These complexes are held together by strong π-stacking interactions. Although these are quantum mechanical effects, their description by quantum chemical methods has proved very hard. We used three semi-empirical methods, PM6-D3H4X, PM6-D3H+ and GFN2-xTB, to model the interactions. Binding to fullerenes was extended to all open conformations of the buckycatcher, and with the proper choice of solvation model and partition functions, we obtained Gibbs free energies of binding that deviated by 1.0–1.5 kcal/mol from the experimental data. Adding three-body dispersion to PM6-D3H+ led to even better agreement. These results agree better with the experimental data than calculations using higher-level methods at a significantly lower fraction of the computational cost. Furthermore, the formation of adducts with $C_{60}$ was studied using dynamical simulations, which helped to build a more complete picture of the behavior of the corannulene pincer with fullerenes. We also investigated the use of exchange-binding models to recover more information on this system in solution. Though the final Gibbs free energies in solution were worsened, gas-phase enthalpies and entropies better mirrored the experimental data. Full article