Novel 3D Force Sensors for a Cost-Effective 3D Force Plate for Biomechanical Analysis.

Three-dimensional force plates are important tools for biomechanics discovery and sports performance practice. However, currently, available 3D force plates lack portability and are often cost-prohibitive. To address this, a recently discovered 3D force sensor technology was used in the fabrication of a prototype force plate. Thirteen participants performed bodyweight and weighted lunges and squats on the prototype force plate and a standard 3D force plate positioned in series to compare forces measured by both force plates and validate the technology. For the lunges, there was excellent agreement between the experimental force plate and the standard force plate in the X-, Y-, and Z-axes (r = 0.950-0.999, p < 0.001). For the squats, there was excellent agreement between the force plates in the Z-axis (r = 0.996, p < 0.001). Across axes and movements, root mean square error (RMSE) ranged from 1.17% to 5.36% between force plates. Although the current prototype force plate is limited in sampling rate, the low RMSEs and extremely high agreement in peak forces provide confidence the novel force sensors have utility in constructing cost-effective and versatile use-case 3D force plates.

Community-based postural control assessment in autistic individuals indicates a similar but delayed trajectory compared to neurotypical individuals.

Autistic individuals exhibit significant sensorimotor differences. Postural stability and control are foundational motor skills for successfully performing many activities of daily living. In neurotypical development, postural stability and control develop throughout childhood and adolescence. In autistic development, previous studies have focused primarily on individual age groups (e.g., childhood, adolescence, adulthood) or only controlled for age using age-matching. Here, we examined the age trajectories of postural stability and control in autism from childhood through adolescents using standardized clinical assessments. In study 1, we tested the postural stability of autistic (n = 27) and neurotypical (n = 41) children, adolescents, and young adults aged 7-20 years during quiet standing on a force plate in three visual conditions: eyes open (EO), eyes closed (EC), and eyes open with the head in a translucent dome (Dome). Postural sway variability decreased as age increased for both groups, but autistic participants showed greater variability than neurotypical participants across age. In study 2, we tested autistic (n = 21) and neurotypical (n = 32) children and adolescents aged 7-16 years during a dynamic postural control task with nine targets. Postural control efficiency increased as age increased for both groups, but autistic participants were less efficient compared to neurotypical participants across age. Together, these results indicate that autistic individuals have a similar age trajectory for postural stability and control compared to neurotypical individuals, but have lower postural stability and control overall.

Movement smoothness during dynamic postural control to a static target differs between autistic and neurotypical children.

BACKGROUND: Autistic children and adults have known differences in motor performance, including postural instability and atypical gross motor control. Few studies have specifically tested dynamic postural control. This is the first study to quantify movement smoothness and its relationship to task performance during lateral dynamic postural control tasks in autism. RESEARCH QUESTION: We sought to test the hypothesis that autistic children would have less smooth movements to lateral static targets compared to neurotypical children, and that this difference would relate to specific movement strategies. METHODS: We used camera-based motion-capture to measure spatiotemporal characteristics of lateral movement of a marker placed on the C7 vertebrae, and of markers comprising trunk and pelvis segments during a dynamic postural movements to near and far targets administered in an immersive virtual environment. We tested a sample of 15 autistic children and 11 age-matched neurotypical children. We quantified movement smoothness using log dimensionless jerk. RESULTS: Autistic children exhibited more medial-lateral pelvic position range of motion compared to neurotypical children, and used a stepping strategy more often compared to neurotypical children. Autistic children also had higher log dimensionless jerk than neurotypical children for motion of the C7 marker. All participants had higher log dimensionless jerk for far targets than for near targets. Autistic children had longer trial durations than neurotypical children, and younger children had longer trial durations than older children across diagnostic groups. SIGNIFICANCE: The stepping strategy observed more often in the autistic group likely contributed to log dimensionless jerk and reduced movement smoothness. This strategy is indicative of either an attempt to prevent an impending loss of balance, or an attempt to compensate for and recover from a loss of balance once it is detected.

Autistic Children Use Less Efficient Goal-Directed Whole Body Movements Compared to Neurotypical Development.

Autistic children have differences in their movements which impact their functional performance. Virtual-reality enables researchers to study movement in safe, engaging environments. We used motion-capture to measure how 7-13-year-old autistic and neurotypical children make whole-body movements in a virtual-reality task. Although children in both groups were successful, we observed differences in their movements. Autistic children were less efficient moving to the target. Autistic children did not appear to use a movement strategy. While neurotypical children were more likely to overshoot near targets and undershoot far targets, autistic children did not modulate their strategy. Using kinematic data from tasks in virtual-reality, we can begin to understand the pattern of movement challenges experienced by autistic children.