Dussault-Picard, C. | Search bioRxiv

bioRxiv2026

Impact of age and surface irregularities on intersegmental and inter-joint coordination during gait

Uneven walking surfaces require adjustments in motor strategies and can thus provide insights into the neuromuscular changes underlying maturation. Also, coordination metrics and variability offer a richer description of motor control mechanisms than standard spatiotemporal parameters, constituting a more sensitive approach to characterize developmental changes. This study aimed to investigate the effects of uneven surfaces on intersegmental coordination, as well as inter-joint coordination and its variability, and to assess the differences in adaptation between age groups when walking on uneven surfaces. Seventy participants (2-29 years), divided into four age groups, completed gait trials on an even and two levels of uneven surfaces while equipped with reflective markers. Mean absolute relative phase and deviation phase of the knee-hip and ankle-knee joint pairs were computed to characterize lower limb inter-joint coordination and variability. In addition, the organization and density of whole-body intersegmental coordination were assessed using correlation networks built from marker acceleration data. Uneven surfaces induced more in-phase inter-joint coupling, reduced network density and increased variability across all age groups. While the organization of intersegmental coordination remained stable, older participants exhibited denser networks, reflecting refined segmental interactions. In contrast, younger participants showed more in-phase joint coordination and higher variability suggesting less mature motor control. The age-related inter-joint coordination differences were emphasized on uneven surfaces, likely reflecting the maturation-related ability to modulate spinal locomotor patterns via supraspinal control, thereby increasing adaptation to environmental perturbations. Highlights- Uneven surfaces induce more in-phase inter-joint coordination. - Uneven surfaces accentuate differences in locomotor strategies across development. - Kinectome density may be a promising indicator of locomotor maturation. - Coordinative variability decreased with neuromotor development.

physiology↗

bioRxiv2024

Harmonization of Margin of Stability Calculations and Investigation of the Impact of Foot Length, Foot Width, Gait Speed, and Body Mass

The margin of stability (MoS), the minimum distance between the extrapolated center of mass and the edges of the base of support (BoS), is one of the most widely used metric to describe the mechanical stability during gait. In the current literature, the markers used to define the edges of the BoS are variable and the MoS model neglects the influence of anthropometric factors, such as foot length, foot width, and body mass. This study aimed to evaluate differences between anteroposterior (AP) and mediolateral (ML) MoS measures using various BoS edge definitions (AP: n = 3 methods, ML: n = 4 methods) and to investigate the impact of foot length, foot width, gait speed, and body mass on the MoS measures. Results show that the BoS edges definition affects the resulting MoS across the entire stance phase (AP: p<0.001 between the 3 methods; ML: p<0.001 between the 4 methods). Moreover, the AP MoS is influenced by foot length (p<0.029), as well as gait speed and body mass on both the AP (gait speed: p<0.001; body mass: p<0.038) and ML (gait speed: p<0.032; body mass: p<0.001) MoS. This study proposes a new approach based on optimal foot markers for defining the edges of the BoS, which may contribute to better assess mechanical stability during gait. Finally, the results suggest that normalizing the MoS (i.e., the AP MoS by foot length, gait speed, and body mass, and the ML MoS by gait speed and body mass) can facilitate comparisons between populations.

bioengineering↗