Applying an ecosystem approach to explore modifiable factors related to the risk for low motor competence in young children.

OBJECTIVES: Early childhood is a crucial phase for motor development in which differences between children can manifest. These differences might be related to factors in ecosystems in which children are raised, of which little is currently known. The current study's purpose was to explore which modifiable factors in children's ecosystems are associated with the odds for low versus higher motor competence (MC) in 4- to 6-year-old children. DESIGN: A cross-sectional study design was conducted to investigate which modifiable social and physical factors in the home environment and direct living environment were associated with differences in MC. METHODS: Children's MC was measured through the Athletic Skills Track in 612 4- to 6-year-olds, from 10 primary schools in Eindhoven, the Netherlands. Parenting practices, characteristics of the home environment, and perceptions of the direct living environment were assessed through parental questionnaires. Hierarchical logistic regression analyses were conducted to evaluate factors associated with low MC in children. RESULTS: The presence of a garden at home and higher perceived sports facilities in the direct living environment decreased the likelihood of children being classified as low MC. Moreover, stronger parental active transportation routines and more discouraging physical activity parenting practices resulted in lower odds of low MC. In addition, girls were more at risk for low MC. CONCLUSIONS: Characteristics of the social and physical home environment and direct living environment were associated with MC disparities during early childhood. Both parenting practices and parental physical activity-involved behaviours are relevant modifiable factors related to differences in children's MC.

"What needs to be seen": An exploration into the visual anticipation behaviour of different skill-level football referees while observing long passes on-field.

It is well established that elite football referees possess superior anticipatory skills in specific game scenarios such as when assessing foul situations. Referees might also have better anticipatory skills in other important scenarios such as when observing a long pass. In these often-occurring situations, a referee has to use visual information to anticipate the outcome of the pass, in particular to foresee any potential infringements that might occur when players battle for ball possession. However, little is known about if and how football referees might anticipate outcomes in these scenarios. The aim of the current study was therefore to analyse the visual anticipatory behaviour of football referees when long passes occur during actual football matches. Elite (N = 4) and sub-elite referees (N = 12) officiated an actual football match while wearing a mobile eye-tracker to analyse their gaze behaviour when long passes occurred (N = 196). The results revealed differences in the way that the elite and sub-elite referees tracked the ball and anticipated the outcome of the ball trajectories. The elite referees used a lower search rate (1.3 vs 1.8 fix/s; p < .05) and were more likely to direct their gaze towards the ball during the moment of kick (77 vs 52%; p < .05) and the early flight-phase of the pass (68 vs 45%; p < .05), and subsequently produced earlier anticipatory eye movements to the player(s) receiving the ball (at 50% vs 60% of the ball flight; p < .05). This earlier anticipation may help the elite referees to better pick-up relevant information about the receivers that could be vital in making adjudications about any potential infringement when the ball does arrive. Referee education programs can use the current study to highlight the importance of visual search behaviour and help referees to adapt a strategy that is beneficial for long-pass situations.

The validity of the 4-Skills Scan A double-validation study.

Adequate gross motor skills are an essential aspect of a child's healthy development. Where physical education (PE) is part of the primary school curriculum, a strong curriculum-based emphasis on evaluation and support of motor skill development in PE is apparent. Monitoring motor development is then a task for the PE teacher. To fulfill this task, teachers need adequate tools. The 4-Skills Scan is a quick and easily manageable gross motor skill instrument; however, its validity has never been assessed. Therefore, the purpose of this study was to assess the construct and concurrent validity of both 4-Skills Scans (version 2007 and version 2015). A total of 212 primary school children (6-12 years old) was requested to participate in both versions of the 4-Skills Scan. For assessing construct validity, children covered an obstacle course with video recordings for observation by an expert panel. For concurrent validity, a comparison was made with the M-ABC-2, by calculating Pearson correlations. Multivariable linear regression analyses were performed to determine the contribution of each subscale to the construct of gross motor skills, according to the M-ABC-2 and the expert panel. Correlations between the 4-Skills Scans and expert valuations were moderate, with coefficients of .47 (version 2007) and .46 (version 2015). Correlations between the 4-Skills Scans and the M-ABC-2 (gross) were moderate (.56) for version 2007 and high (.64) for version 2015. It is concluded that both versions of the 4-Skills Scans are satisfactory valid instruments for assessing gross motor skills during PE lessons.

The Athletic Skills Track: Age- and gender-related normative values of a motor skills test for 4- to 12-year-old children.

OBJECTIVES: The aim of the presented study is to provide age- and gender-related normative values and MQ values for a motor skills test, the Athletic Skills Track, among 4- to 12-year-old children. DESIGN: Cross-sectional. METHODS: In 2016, a total of 7977 Dutch children, 4036 boys (mean age 8.6 years, SD 2.1) and 3941 girls (mean age 8.6 years, SD 2.1), performed an age-related version of the Athletic Skills Track (AST). The AST is a track consisting of 5-7 fundamental movement skill tasks that should be completed as fast as possible. The children performed the test during a regular physical education (PE) lesson under the supervision of their own PE teacher. For each version of the AST (AST-1: n=917; AST-2: n=3947; AST-3: n=3213) age- and gender-related reference centiles were derived from the gathered data using the Lambda, Mu, Sigma (LMS) method. RESULTS: All children completed the AST within 60s (mean 29.6s, SD 7.7). An independent samples t-test showed that boys were significantly faster in completing the track than girls, except for the 4-year-old boys. Therefore, age- and gender-related reference centiles were derived. The reference curves demonstrate an almost linear decrease in time to complete AST-1 and AST-2 with increasing age. CONCLUSIONS: The present study provides age- and gender-related normative values and MQ values for the AST among 4- to 12-year-old Dutch children. With these normative values PE teachers can interpret children's performance on the AST.

Gaze behaviour during interception in children with spastic unilateral cerebral palsy.

Anticipatory gaze behaviour during interceptive movements was investigated in children with Spastic Unilateral Cerebral Palsy (SUCP), and related to the side of the intracerebral lesion. Five children with lesions of the right hemisphere (RHL) and five children with lesions of the left hemisphere (LHL) had to walk towards and intercept a ball that moved perpendicular to the walking path. Interception accuracy and gaze patterns were measured in a no-occlusion and occlusion condition, in which the ball was occluded from view for half of its trajectory. There was a clear support for a relationship between gaze behaviour and success in interception performance, with some evidence for the presence of anticipatory gaze behaviour. There were also differences in gaze behaviour between children with RHL and children with LHL that might be related to planning, but these did not affect interception accuracy. It is concluded that gaze behaviour during interceptive movements is anticipatory, and at least partly dependent on the lesional side.

The relative timing between eye and hand in rapid sequential pointing is affected by time pressure, but not by advance knowledge.

The present study examined the effect of timing constraints and advance knowledge on eye-hand coordination strategy in a sequential pointing task. Participants were required to point at two successively appearing targets on a screen while the inter-stimulus interval (ISI) and the trial order were manipulated, such that timing constraints were high (ISI = 300 ms) or low (ISI = 450 ms) and advance knowledge of the target location was present (fixed order) or absent (random order). Analysis of eye and finger onset and completion times per segment of the sequence indicated that oculo-manual behaviour was in general characterized by eye movements preceding the finger, as well as 'gaze anchoring' (i.e. eye fixation of the first target until completion of the finger movement towards that target). Advance knowledge of future target locations lead to shorter latency times of eye and hand, and smaller eye-hand lead times, which in combination resulted in shorter total movement times. There was, however, no effect of advance knowledge on the duration of gaze anchoring. In contrast, gaze anchoring did change as a function of the interval between successive stimuli and was shorter with a 300 ms ISI versus 450 ms ISI. Further correlation analysis provided some indication that shorter residual latency is associated with shorter pointing duration, without affecting accuracy. These results are consistent with a neural mechanism governing the coupling of eye and arm movements, which has been suggested to reside in the superior colliculus. The temporal coordination resulting from this coupling is a function of the time pressure on the visuo-manual system resulting from the appearance of external stimuli.

Perception and action in golf putting: skill differences reflect calibration.

We assessed how golfers cope with the commonly observed systematic overshoot errors in the perception of the direction between the ball and the hole. Experiments 1 and 2, in which participants were required to rotate a pointer such that it pointed to the center of the hole, showed that errors in perceived direction (in degrees of deviation from the perfect aiming line) are destroyed when the head is constrained to move within a plane perpendicular to the green. Experiment 3 compared the errors in perceived direction and putting errors of novice and skilled players. Unlike the perceived direction, putting accuracy (in degrees of deviation from the perfect aiming line) was not affected by head position. Novices did show a rightward putting error, while skilled players did not. We argue that the skill-related differences in putting accuracy reflect a process of recalibration. Implications for aiming in golf are discussed.

Visual guidance of interceptive actions in children with spastic unilateral cerebral palsy is influenced by the side of the lesion.

PURPOSE: To determine the type of visual information used by children with spastic unilateral cerebral palsy (SUCP) in order to intercept a ball and to verify whether this information was dependent on the side of the lesion. More specifically, it was examined whether the interception was controlled on the basis of a time or a distance strategy, initiating the catch when the ball is at a fixed time interval or at a fixed distance from the point of interception. METHODS: Three groups of children were included. Children with either a left sided (LHL) or a right sided lesion (RHL) and children without a lesion [typically developing (TD)] intercepted a ball from a conveyor belt. In order to intercept the ball successfully they had to walk and to reach for the ball at the interception point 4 m away. RESULTS: Children with LHL had a longer decision time and started their reach movement earlier. In 56% of the children with LHL a distance strategy was observed, while in the TD and the children with RHL predominantly a time strategy was found. CONCLUSIONS: The side of the lesion influences the visual information used to initiate interceptive actions.

Balance problems during obstacle crossing in children with Developmental Coordination Disorder.

The present study investigated the visuomotor and balance limitations during obstacle crossing in typically developing (TD) children and those with Developmental Coordination Disorder (DCD) (7-9 years old; N=12 per group). Spatiotemporal gait parameters as well as range and velocity of the centre of mass (COM) were determined in three conditions: overground walking at a self-selected speed, crossing a low obstacle and crossing a high obstacle (5% or 30% of the leg length, respectively). Both groups walked more slowly during obstacle crossing than walking over level ground. In addition, both groups exhibited a significant decrease in the spatial variability of their foot placements as they approached the obstacle, which was then negotiated with a similar strategy. There were no differences in approach distance, length of lead and trail step, or lead and trail foot elevation. Compared to walking over level ground, obstacle crossing led to a longer swing phase of the lead and trail foot and increased maximal medio-lateral COM velocity. In children with DCD, however, medio-lateral COM velocity was higher and accompanied by significantly greater medio-lateral COM amplitude. In conclusion, the results indicate that while TD-children and those with DCD exhibit satisfactory anticipatory control and adequate visual guidance, the latter group have a reduced ability to control the momentum of the COM when crossing obstacles that impose increased balance demands.

On a multistable dynamic model of behavioral and perceptual infant development.

In this theoretical work, we treat behavioral and perceptual issues on an equal footing and examine the emergence of mutually exclusive behavioral patterns and perceptual variables during infant development from the perspective of multistable competitive dynamic systems. Accordingly, behavioral modes and modes of perception compete with each other for activation. One and only one mode survives the mode-mode competition, which accounts for the incompatibility of modes being considered. However, the winning behavioral or perceptual state is not predefined. Rather, we argue that during particular stages of maturation multiple modes coexist for the same set of developmental, body-scaled, and environmental parameters or constraints. The winning behavioral or perceptual state depends on these parameters as well as on initial conditions as operationalized in terms of previously performed behaviors or utilized perceptual stimuli. We give explicit examples of our approach and address the emergence of two-handed grasping and catching movements and the emergence of monocular and binocular vision during infant development. In particular, we propose that the emergence of midline crossing movements in 3- to 6-month-old infants involves two independent but interaction control parameters: a body-scaled and a developmental one. Likewise, we argue that the onset of binocularity in infants involves two independent but interaction control parameters: a developmental and an environmental one.

Visual guidance during an interception task in children with Spastic Hemiparetic Cerebral Palsy.

The aims of the study are to determine the presence of adjustments in walking behaviour of children with Spastic Hemiparetic Cerebral Palsy (SHCP) during the interception of a moving ball and, whether the angle between the ball and the participant is kept constant. This would support the use of the so-called bearing angle (BA) strategy in interception of the object. Children with left hemisphere damage intercepted a ball from a conveyor belt at three different velocities, from a frontal or lateral orientation and with their impaired or less-impaired hand. The participants walked from a distance of 4m perpendicularly to the belt. Children seemed to have less successful trials when grasping with the impaired hand. The results showed that the walking velocity was adjusted to the ball velocity. When they grasped with the impaired hand, children initially moved faster to the interception point, while closer to the belt significant slower. The BA showed less variation over the trajectory when the children grasped with their less-impaired hand or when the ball velocity increased. It was concluded that children with SHCP were able to take their impairment into account as indicated by adjustments in walking behaviour. However, these adjustments in walking velocity were not sufficient to compensate totally for the limited reaching ability in the impaired hand. As a result of these adjustments, the amount of variation from the constant BA seemed to deviate more from typically developing children when grasping with impaired hand than when grasping with less-impaired hand.

Early control of reaching: effects of experience and body orientation.

Although research suggests that experience may be a better indicator of the acquisition of certain abilities by infants than age, little work addresses this issue in the development of reaching movements in particular. This longitudinal study fills this gap by verifying the effect of practice time on more- and less-skilled reachers of the same age group in different body orientations. Less- (n=6) and more-skilled (n=4) reachers were evaluated at the acquisition of reaching and again after 1 month of spontaneous practice. Kinematic analyses examined 3D wrist motion during reaching trials in supine (0 degrees ), reclined (45 degrees ) and seated (70 degrees ) orientations. The results indicated that skill level was a relevant factor in dealing with gravitational constraints imposed by different body orientations. Time of practice affected the way less- and more-skilled reachers explored and adapted the kinematic parameters of reaching to constraints imposed by body orientations. These findings suggest that not only age, but also experience and body orientations are important constraints that should be taken into account when examining infant reaching development.

Interception of moving objects while walking in children with spastic hemiparetic cerebral palsy.

PURPOSE: The purpose of the study was to examine the coordination of reaching and walking behaviour when children with Spastic Hemiparetic Cerebral Palsy (SHCP) intercept an approaching and hence externally-timed object. METHOD: Using either the impaired or non-impaired arm, children intercepted a ball approaching from a fixed distance with one of three velocities. Each participant's initial starting position was scaled to their maximum walking velocity determined prior to testing; for the medium ball velocity, participants would arrive at the point of interception at the correct time if they walked with their maximum velocity. RESULTS: Children with SHCP adapted their reaching and walking behaviour to the different ball approach velocities. These adaptations were exhibited when using the impaired and non-impaired arm, and resulted in similar outcome performance irrespective of which arm was used. Still, children with SHCP found it necessary to increase trunk movement to compensate for the decreased elbow excursion and a decreased peak velocity of the impaired arm. CONCLUSION: Children with SHCP exhibited specific adaptations to their altered movement capabilities when performing a behaviourally-realistic task. The provision of an external timing constraint appeared to facilitate both reaching and walking movements and hence could represent a useful technique in rehabilitation.

Spatio-temporal parameters in infant's reaching movements are influenced by body orientation.

Many studies have demonstrated that the seated position is more effective in promoting reaching movements when compared with supine. The aim of this longitudinal study was to verify the effect of seated and supine positions on spatio-temporal parameters of reaching in 4-6-month-old infants. Four infants were observed during reaching trials in both positions. A total of 235 reaches were analyzed by using the 3D movement reconstruction. Our results showed that frequency of reaching and straightness index increased over age. Significant differences between the positions were observed at 4 months, when the frequency increased and the duration and deceleration time decreased in the seated position. There were no significant differences at 5 and 6 months. These findings suggest that young infants are able to change kinematical parameters of reaching to adapt themselves to intrinsic and extrinsic constraints (i.e. age and position).

External timing constraints facilitate performance of everyday interceptive actions in children with Spastic Hemiparetic Cerebral Palsy.

We examined how children with Spastic Hemiparetic Cerebral Palsy (SHCP) perform interceptive actions they experience in daily life. Children were required to walk towards and intercept a stationary ball or a moving ball, with either their impaired or non-impaired arm. In the stationary ball condition the child was free to determine the speed of their response (internal timing), whereas in the moving ball condition there was a restricted time available (external timing). It was found that the reach movements of the non-impaired arm were different to the impaired arm, and were characterized by some of the typical movement limitations imposed by SHCP. However, there was no evidence of increased contribution from trunk motion or a lengthening of reach movement time or deceleration time. Instead, there was a coordinated change with the walking kinematics, whereby the children spent proportionately more time slowing down as they approached the point of interception when reaching with the impaired arm. There were also several differences in the response when intercepting a moving ball compared to a stationary ball. When the timing constraints were imposed externally (moving ball) rather than internally (stationary ball), children reached with a reduced movement time and deceleration time, and an increased peak wrist velocity and elbow excursion. These adaptations to behaviour were necessary to deal with the restricted time available to make the interception in the moving ball condition compared to when the ball was stationary, and reveal how children with SHCP coordinate walking and reaching when performing natural interceptive actions.

Visual contribution to walking in children with Developmental Coordination Disorder.

BACKGROUND: The motor co-ordination problems of children with Developmental Coordination Disorder (DCD) have been frequently associated with poor visuospatial processing. In order to extend these findings mainly based on fine motor experiments, the present study investigates the contribution of vision to the control of walking in children with DCD. METHODS: Children with DCD (n = 12) walked at their preferred speed on a straight, firm and uncluttered walkway in a condition with normal lighting and in a dark condition. Spatiotemporal gait variables were assessed by means of a three-dimensional ProReflex camera system and compared with the gait pattern of matched, typically developing (TD) children (n = 12). RESULTS: In normal lighting, the gait pattern of both groups was similar, with the exception of subtle differences in the temporal phasing, showing a slightly longer support phase in the children with DCD. In the dark, step frequency and step length were decreased in the children with DCD, resulting in a significantly slower walking velocity. In addition, the medio-lateral excursion of the centre of mass tended to increase in this group. In the TD children, adaptations to the spatiotemporal pattern remained absent. CONCLUSIONS: These results suggest that children with DCD are more dependent on global visual flow information than TD children for the maintenance of balance and the control of velocity during walking. This increased dependency on visual control might be associated with a poorly developed internal sensorimotor model.

Catching optical information for the regulation of timing.

Recent research almost unambiguously refutes the hypothesis that the timing of interceptive actions is solely based on the relative rate of expansion [i.e. tau(psi)]. The aim of the present experiment was to evaluated the merits of eight alternative informational variables that recently have been proposed in the literature (i.e. psi, theta, delta, tau(psi), tau(theta), tau(delta), tau(psi, theta), zeta). Participants (n=7) were required to regulate the spatio-temporal characteristics of their reach and grasp to catch a ball approaching on a constant spatial trajectory. To identify the information used to regulate the timing of the catch we examined the qualitative effects of ball speed (0.5, 1.0, 1.5, 2.0, and 2.5 m/s) and viewing (monocular versus binocular) on the kinematics of the catch. Subsequently, we directly assessed the quantitative relationship between informational variables and the timing of reach onset and hand closure. The findings raised serious doubts against the use of variables that specified the time-to-contact between the ball and the point of observation (i.e. relative rate of expansion and disparity). Further, optical variables solely confined to the trajectory of the ball (i.e. the absolute rate of expansion) did yield positive results for the timing of reach onset but not for the timing of hand closure. Only variables that were related to the closure of the gap between hand and ball were found to contribute to the timing of hand closure. These results suggest that information related to the constriction of the optical gap between end-effector and ball becomes more important with approach, whereas the contribution of the absolute rate of expansion becomes less leading.

Safety in road crossing of children with cerebral palsy.

AIM: Children with cerebral palsy (CP) are regularly confronted with physical constraints during locomotion. Because abnormalities in motor control are often related to perceptual deficits, the aim of this study was to find out whether children with CP were able to walk across a road as safely as their non-handicapped peers. METHOD: Ten children with CP and 10 non-handicapped children aged 4-14 y were asked to cross a simulated road if they felt the situation was safe. RESULTS: With respect to safety and accuracy of crossings, the behaviour of children with CP was comparable with that of non-handicapped children. However, a closer examination of children's individual crossing behaviour showed considerable differences within the CP group. In contrast to children with damage to the left hemisphere, children with damage to the right hemisphere made unsafe decisions and did not compensate for them by increasing walking speed. CONCLUSION: The differences in unsafe behaviour and in the ability to compensate for it within the group of children with CP might be related to damage to specific regions of the brain that are involved in the processing of spatial or temporal information.

Foot-targeting in reaching and grasping.

Foot positioning was investigated when right-handed (Experiment One) and left handed adults (Experiment Two) stopped walking to grasp a stationary 70 mm ball at shoulder height. In both experiments centroid location formed by the toe and heel coordinates relative to the object was highly consistent within a target-location condition, demonstrating a foot-targeting phenomenon. Centroid location in the anterior-posterior direction was uninfluenced by grasping hand but the centroid shifted right for left hand grasps and left for right hand grasps. With the target either centrally located or on the same side as the dominant hand, foot positioning brought the grasping hand closer to the target in the medial-lateral direction. When the target object was aligned with the shoulder opposite the dominant hand both groups adopted foot positions to the left of the target. Thus, neither group adopted optimal foot position when the target was located opposite their dominant hand. Foot orientation angle relative to the target was also influenced by choice of grasping hand. Collectively, the findings demonstrate a close association between grasping hand and foot position when approaching to reach and grasp an object but also suggest that foot-dominance may influence medial-lateral centroid location.