Perceptual-motor regulation in locomotor pointing while approaching a curb

Abstract

Locomotor pointing is a task that has been the focus of research in the context of sport (e.g. long jumping and cricket) as well as normal walking. Collectively, these studies have produced a broad understanding of locomotor pointing, but generalizability has been limited to laboratory type tasks and/or tasks with high spatial demands. The current study aimed to generalize previous findings in locomotor pointing to the common daily task of approaching and stepping on to a curb. Sixteen people completed 33 repetitions of a task that required them to walk up to and step onto a curb. Information about their foot placement was collected using a combination of measures derived from a pressure-sensitive walkway and video data. Variables related to perceptual-motor regulation were analyzed on an inter-trial, intra-step and inter-step level. Similar to previous studies, analysis of the foot placements showed that, variability in foot placement decreased as the participants drew closer to the curb. Regulation seemed to be initiated earlier in this study compared to previous studies, as shown by a decreasing variability in foot placement as early as eight steps before reaching the curb. Furthermore, it was shown that when walking up to the curb, most people regulated their walk in a way so as to achieve minimal variability in the foot placement on top of the curb, rather than a placement in front of the curb. Combined, these results showed a strong perceptual-motor coupling in the task of approaching and stepping up a curb, rendering this task a suitable test for perceptual-motor regulation in walking.

Regulation of locomotor pointing across the lifespan: Investigating age-related influences on perceptual-motor coupling

“…To facilitate comparison of the current study with previous research and to prevent the participants from producing the same stereotypical walk each time, they were required to place one of their early steps onto a target on the ground (a blue anti-slip mat, dimensions: 30 cm long and 150 cm wide), which was placed in 10 different positions ranging from 1 to 2.5 times the a-priori measured step lengths from the start of the walkway [ 7 ]. In addition, a final condition was added in which no early stepping target was presented and the participants completed the task unconstrained.…”

“…Research has shown that this type of locomotor pointing is made possible through an intimate coupling of perception and action [ 1 – 6 ]. The regulation required for such a task is not limited to athlete populations, but rather, is also used by members of the general population on a daily basis when performing locomotor pointing tasks, such as approaching and stepping onto a curb [ 7 ]. Whilst these studies would suggest that locomotor pointing is a skill that can be comfortably performed by all humans, research concerning age-related changes in locomotor pointing in otherwise healthy populations is limited.…”

“…In subsequent research, it was shown that people exhibit the same perceptual-motor coupling strategy as shown in the long-jump in other locomotor pointing tasks, such as walking to a target [ 7 – 12 ]. In these studies, the relationship between the gait adjustments required and gait adjustments produced was measured for each step in the approach to a target as the degree to which deviations from the average step length were related to the adjustment required.…”

“…Similarly, adjustment produced was measured as the difference between a certain step’s length and the average step length [ 1 , 5 , 9 , 12 ]. A recent study described the strength of this relationship between adjustment required and adjustment produced as representing the ‘strength of perceptual-motor coupling’ [ 7 ]. In this interpretation, a stronger coupling recorded for a specific step would indicate that more of the required adjustment is being made in that specific step.…”

“…That is, similarities in the regulation of foot placement exist between tasks performed in high-performance settings (e.g. long jump), as well as in everyday activities, such as walking to and stepping onto targets [ 8 ] and approaching and stepping onto a curb [ 7 ]. This is helpful in broadening the understanding of perceptual-motor coupling in locomotor settings.…”