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There is a positive relationship between children's movement competence and physical activity, with a further relationship established between physical activity and childhood obesity. The Movement Oriented Games Based Assessment (MOGBA) is a delivery and assessment intervention designed to improve children's complex movement skills, based on principles of motor development and assessment theories. MOGBA aims to improve children's movement competence, physical fitness and self-perceptions (physical and game) and increase children's moderate-to-vigorous physical activity (MVPA). MOGBA is to be used in the 'Made to Play' initiative, involving 105 sports and activity programs across 21 countries, involving over 25 million children. A multi-site cluster randomized controlled trial will take place across three global sites (UK, Ireland and Australia). Each site will recruit eight primary schools (four experiment, four control) with each school providing two separate classes of children from age ranges 8-12 years (Site n = ~300, total n = 904). After baseline assessments, schools will be randomly allocated to an experimental or wait-list control group. Following two half-day workshops, trained facilitators will deliver the MOGBA intervention for 9 weeks. The main intervention components include delivery of 14 games-based activities with associated assessments of children's movement and differentiation to meet children's needs by manipulating space, effort and relationships. The primary outcome of the trial is to improve children's' movement competence (The Dragon Challenge), with secondary outcomes of improving children's' in-activity and leisure-time MVPA (5-day accelerometer), physical fitness (standing long jump and push ups) and self-perceptions (physical and game). Data will be analysed using multilevel modelling approaches. The MOGBA intervention has been designed to improve children's movement competence and scalable interventions based on MOGBA could be applied across programs within the Made to Play initiative, globally. The trial is registered at the Australia New Zealand Clinical Trial Registry (ACTRN12619001320145p, 27 Sep 2019).

How are eyes and head adapted to meet the demands of visual exploration in different tasks and environments? In two studies, we measured the horizontal movements of the eyes (using mobile eye tracking in Studies 1 and 2) and the head (using inertial sensors in Study 2) while participants completed a walking task and a search and retrieval task in a large, outdoor environment. We found that the spread of visual exploration was greater while searching compared with walking, and this was primarily driven by increased movement of the head as opposed to the eyes. The contributions of the head to gaze shifts of different eccentricities was greater when searching compared to when walking. Findings are discussed with respect to understanding visual exploration as a motor action with multiple degrees of freedom.

Spatial intermittent motion mechanisms encompass non-continuously operating mechanisms in spacecraft, such as rotary tables, Solar Array Drive Assemblies (SADA), and spaceborne camera focusing mechanisms. Among these, failure assessment proves most complex for long-duration intermittent motion mechanisms due to their nonlinear polymorphic degradation characteristics. This paper proposes a probability-based time-dependent reliability analysis model to quantify the reliability of spaceborne optical detector focusing mechanisms, thereby establishin an analytical methodology for intermittent motion mechanisms subjected to long-term cyclic operations. Through profound deconstruction of reliability dependency chains and influence domain intersections among multiple kinematic pairs, the critical weak links contributing most significantly to system failure and their associated failure modes are identified. A dynamically equivalent approach is introduced, which transforms stochastic loading into equivalent constant-amplitude cyclic fatigue loading. This addresses the challenge in space mechanism reliability analysis where characterizing generalized loading is difficult due to complex operational profiles and the impracticality of acquiring sufficient sample data through extensive ground testing. Accounting for space system non-repairability and operational intervals/durations uncertainties, the model treats strength degradation as cumulative damage from multiple stochastically independent operational cycles. The analysis precision and efficiency are enhanced by implementing double-truncated probability distributions. The paper demonstrates the model’s application through case studies and validates its accuracy, providing benchmark references for engineering applications and revealing underlying mechanisms governing failure evolution.

In our prior studies, human participants were required to generate long sequences of targeted hand movement when task difficulty varied between conditions, and where full vision of the hand and target was always available. The movement amplitude—that is, the actual distance travelled—for each movement was measured; consecutive movement amplitude values were formed into time series; then, the time series were submitted to spectral analysis. As task difficulty increased, there was a pink-to-white-noise shift in movement amplitude time-series structure. Those changes could be attributed to a difficulty-induced increase in the need to engage visual feedback processes, which maintain accurate guidance of the hand to the target. The current study was designed to provide a more direct test of the hypothesis that difficulty-induced increases in visual feedback processing modulate movement amplitude time-series structure. To that end, we examined cyclical aiming performance under four unique conditions created from the crossing of two index of difficulty (2 and 5 bits) and two visual feedback (visual feedback and no-visual feedback) conditions. That allowed us to examine how variations in visual feedback quality might influence difficulty-induced changes in time-series structure. In the visual feedback condition, we predicted that the increase in difficulty should result in a pink-to-white-noise shift in time-series structure. If that expected shift resulted from increased engagement of visual feedback processing, then in the no-visual feedback condition—where visual feedback processing was disabled—we should observe a strengthened pink-noise time-series structure that does not change with the increase in difficulty. The current results confirmed those predictions. That provides further support for the hypothesis that engagement of closed-loop visual feedback processing modulates movement amplitude time-series structure.

People rely upon sensory information in the environment to guide their actions. Ongoing goal-directed arm movements are constantly adjusted to the latest estimate of both the target and hand’s positions. Does the continuous guidance of ongoing arm movements also consider the latest visual information of the position of obstacles in the surrounding? To find out, we asked participants to slide their finger across a screen to intercept a laterally moving virtual target while moving through a gap that was created by two virtual circular obstacles. At a fixed time during each trial, the target suddenly jumped slightly laterally while still continuing to move. In half the trials, the size of the gap changed at the same moment as the target jumped. As expected, participants adjusted their movements in response to the target jump. Importantly, the magnitude of this response depended on the new size of the gap. If participants were told that the circles were irrelevant, changing the gap between them had no effect on the responses. This shows that obstacles’ instantaneous positions can be considered when visually guiding goal-directed movements.

We develop a physics-based kinematic model of martial arts movements incorporating rotation and angular momentum, extending prior analyses. Here, our approach is designed for a classroom environment; we begin with a warm-up exercise introducing counter-intuitive aspects of rotational motion before proceeding to a set of model collision problems that are applied to martial arts movements. Finally, we develop a deformable solid-body mechanics model of a martial arts practitioner suitable for an intermediate mechanics course. We provide evidence for our improved model based on calculations from biomechanical data obtained from prior reports as well as time-lapse images of several different kicks. In addition to incorporating angular motion, our model explicitly makes reference to friction between foot and ground as an action-reaction pair, showing that this interaction provides the motive force/torque for nearly all martial arts movements. Moment-of-inertia tensors are developed to describe kicking movements and show that kicks aimed high, towards the head, transfer more momentum to the target than kicks aimed lower, e.g. towards the body.

There is a positive relationship between children’s movement competence and physical activity, with a further relationship established between physical activity and childhood obesity. The Movement Oriented Games Based Assessment (MOGBA) is a delivery and assessment intervention designed to improve children’s complex movement skills, based on principles of motor development and assessment theories. MOGBA aims to improve children’s movement competence, physical fitness and self-perceptions (physical and game) and increase children’s moderate-to-vigorous physical activity (MVPA). MOGBA is to be used in the ‘Made to Play’ initiative, involving 105 sports and activity programs across 21 countries, involving over 25 million children. A multi-site cluster randomized controlled trial will take place across three global sites (UK, Ireland and Australia). Each site will recruit eight primary schools (four experiment, four control) with each school providing two separate classes of children from age ranges 8–12 years (Site n = ~300, total n = 904). After baseline assessments, schools will be randomly allocated to an experimental or wait-list control group. Following two half-day workshops, trained facilitators will deliver the MOGBA intervention for 9 weeks. The main intervention components include delivery of 14 games-based activities with associated assessments of children’s movement and differentiation to meet children’s needs by manipulating space, effort and relationships. The primary outcome of the trial is to improve children’s’ movement competence (The Dragon Challenge), with secondary outcomes of improving children’s’ in-activity and leisure-time MVPA (5-day accelerometer), physical fitness (standing long jump and push ups) and self-perceptions (physical and game). Data will be analysed using multilevel modelling approaches. The MOGBA intervention has been designed to improve children’s movement competence and scalable interventions based on MOGBA could be applied across programs within the Made to Play initiative, globally. The trial is registered at the Australia New Zealand Clinical Trial Registry (ACTRN12619001320145p, 27 Sep 2019).

The kinematic synthesis of compliant mechanisms based on flexure hinges is not an easy task. A commonly used method is the equivalent rigid model, which involves replacing the flexure hinges with rigid bars connected with lumped hinges using the already known methods of synthesis. This way, albeit simpler, hides some interesting issues. This paper addresses the elasto-kinematics and instantaneous invariants of flexure hinges with a direct approach, making use of a nonlinear model to predict their behaviour. The differential equations that govern the nonlinear geometric response are given in a comprehensive form and are solved for flexure hinges with constant sections. The solution to the nonlinear model is then used to obtain an analytical description of two instantaneous invariants: the centre of instantaneous rotation (c.i.r.) and the inflection circle. The main result is that the c.i.r. evolution, namely the fixed polode, is not conservative but is loading-path dependent. Consequently, all other instantaneous invariants are loading-path dependent, and the property of instantaneous geometric invariants (independent of the motion time law) can no longer be used. This result is analytically and numerically evidenced. In other words, it is shown that a careful kinematic synthesis of compliant mechanisms cannot be addressed by only considering the kinematics as rigid mechanisms, and it is essential to take into consideration the applied loads and their histories.

During precise gaze shifts, eye, head, and body movements exhibit synergic relations. In the present study, we tested the existence of behavioural synergic relations between eye and postural movements in a goal-directed, precise, visual search task (locate target objects in large images). More precisely, we tested if postural control could be adjusted specifically to facilitate precise gaze shifts. Participants also performed a free-viewing task (gaze images with no goal) and a fixation task. In both search and free-viewing tasks, young participants (n = 20; mean age = 22 years) were free to move their eyes, head, and body segments as they pleased to self-explore the images with no external perturbation. We measured eye and postural kinematic movements. The results showed significant negative correlations between eye and postural (head and upper back) movements in the precise task, but not in the free-viewing task. The negative correlations were considered to be stabilizing and synergic. Indeed, the further the eyes moved, the more postural variables were adjusted to reduce postural sway. These results suggest that postural control was adjusted to succeed in subtle and active self-induced precise gaze shifts. Furthermore, partial correlations showed significant relations between (1) task performance to find target objects and (2) synergic relations between eye and postural movements. These later results tend to show that synergic eye-postural relations were performed to improve the task performance in the precise visual task.

Essential tremor (ET) is a movement disorder characterized primarily by action tremor which affects the regulation of movements. Disruptions in cerebello-thalamocortical networks could interfere with cognitive control over actions in ET, for example, the ability to suppress a strong automatic impulse over a more appropriate action (conflict control). The current study investigated whether ET impacts conflict control proficiency. Forty-one ET patients and 29 age-matched healthy controls (HCs) performed a conflict control task (Simon task). Participants were instructed to give a left or right response to a spatially lateralized arrow (direction of the arrow). When the action signaled by the spatial location and direction of the arrow were non-corresponding (induced conflict), the inappropriate action impulse required suppression. Overall, ET patients responded slower and less accurately compared to HCs. ET patients were especially less accurate on non-corresponding conflict (Nc) versus corresponding (Cs) trials. A focused analysis on fast impulsive response rates (based on the accuracy rate at the fastest reaction times on Nc trials) showed that ET patients made more fast errors compared to HCs. Results suggest impaired conflict control in ET compared to HCs. The increased impulsive errors seen in the ET population may be a symptom of deficiencies in the cerebello-thalamocortical networks, or, be caused by indirect effects on the cortico-striatal pathways. Future studies into the functional networks impacted by ET (cortico-striatal and cerebello-thalamocortical pathways) could advance our understanding of inhibitory control in general and the cognitive deficits in ET.