Control of human locomotion under various task constraints

Abstract

The goal of this study was to identify the control mechanism used for locomotion pointing regulation under different external temporal constraints. Subjects ( n=8) had to walk on a treadmill through a number of virtual hallways and cross a pair of gliding doors that opened and closed at a constant preset frequency (0.5 Hz or 1 Hz). Crossing performance, step durations, and step lengths were used as dependent measures. The results revealed the regulation of locomotion occurred earlier and was more pronounced at 0.5 Hz than at 1 Hz, making performance better at 0.5 Hz. Nevertheless at the two frequencies the control mechanism appears similar; it is grounded on information movement coupling. This control mechanism allows for the production of specific behavior according to the task constraints.

Perception-Movement Coupling in the Regulation of Step Lengths When Approaching an Obstacle

“…The temporal constraints generated a specific functional behavior to control the regulation. Like those of Montagne et al (2002) and Buekers, Montagne, De Rugy, et al (1999), our results reveal the proportional relationship between the temporal constraints and the step at which regulation occurs. This relationship expresses the nature of perceptionmovement coupling.…”

“…It underlines the adaptation of the person-environment system and the systematic role played by temporal and spatial constraints. The task constraints play an important role: they define at a given step the initiation of regulation (e.g., Bradshaw & Sparrow, 2001;Montagne et al, 2002). In addition, they define the nature of regulation (Renshaw & Davids, 2004).…”

“…In the study by Montagne et al (2002), in a virtual environment coupled to a treadmill, participants had to walk through a number of virtual hallways and through a pair of doors that opened and closed at a frequency of 0.5 Hz or 1 Hz. The results showed that the increased duration of the opening-closing cycle (i.e., 1 Hz) allowed the person to initiate regulation sooner (i.e., S-2).…”

“…According to Lee et al (1982) in the long jumping task and Montagne, Buekers, De Rugy, Camachon and Laurent (2002) in the pointing task in a virtual environment, the standard deviation of step lengths increased during the last steps. These regulations of step lengths resulted in achieving an optimal foot positioning when aiming at the target (Lee et al, 1982).…”

Perceiving affordances for fitting through apertures.

“…Despite the costs associated with erroneous motor decisions, several studies indicated that even adults might fail to leave a sufficient safety margin and attempt to fit their bodies through impossibly small apertures. For example, participants slightly misjudged their ability to pass through doorways without becoming wedged while walking normally (Gordon & Rosenblum, 2004; Warren & Whang, 1987), walking while carrying a horizontal pole (Wagman & Taylor, 2005), rolling in a wheelchair (Flascher, Shaw, Kader, & Aromin, 1995; Higuchi, Takada, Matsuura, & Imanaka, 2004), and walking on a treadmill through a virtual oscillating aperture projected on a screen (Buekers, Montagne, de Rugy, & Laurent, 1999; Montagne, Buekers, de Rugy, Camachon, & Laurent, 2002). Similarly, observers slightly misjudged their ability to pass under an overhead barrier with sufficient clearance to walk without banging their heads (Gordon & Rosenblum, 2004).…”