Visual planning for locomotion includes judgment of:
- Obstacles distance, size and height relative to body size as well as skill level
- Gap size
- Slope
- Surface properties – slippery, soft, firm. stable
- Involves determining the the height and distance to the obstacle
- Planning appropriate foot placement and limb elevation for successful clearance.
Bibliography Adolph, K. E., et al (2010). How Do You Learn to Walk ? Thousands of Steps and Dozens of Falls Per Day.
Buckley, J. G., Timmis, M. a, Scally, A. J., & Elliott, D. B. (2011). When is visual information used to control locomotion when descending a kerb? PloS one, 6(4), e19079.
Descending kerbs during locomotion involves the regulation of appropriate foot placement before the kerb-edge and foot clearance over it. It also involves the modulation of gait output to ensure the body-mass is safely and smoothly lowered to the new level. Previous research has shown that vision is used in such adaptive gait tasks for feedforward planning, with vision from the lower visual field (lvf) used for online updating. The present study determined when lvf information is used to control/update locomotion when stepping from a kerb.
Cisek, P., & Kalaska, J. F. (2010). Neural Mechanisms for Interacting with a World Full of Action Choices. Annual Review of Neuroscience, (March), 269–298.
Wilmut, K., & Barnett, A. L. (2011). Locomotor behaviour of children while navigating through apertures. Experimental brain research. 210(2), 185–94.
During everyday locomotion, we encounter a range of obstacles requiring specific motor responses; a narrow aperture which forces us to rotate our shoulders in order to pass through is one example. In adults, the decision to rotate their shoulders is body scaled (Warren and Whang in J Exp Psychol Hum Percept Perform 13:371-383, 1987), and the movement through is temporally and spatially tailored to the aperture size (Higuchi et al. in Exp Brain Res 175:50-59, 2006; Wilmut and Barnett in Hum Mov Sci 29:289-298, 2010). The aim of the current study was to determine how 8-to 10-year-old children make action judgements and movement adaptations while passing through a series of five aperture sizes which were scaled to body size (0.9, 1.1, 1.3, 1.5 and 1.7 times shoulder width). Spatial and temporal characteristics of movement speed and shoulder rotation were collected over the initial approach phase and while crossing the doorway threshold. In terms of making action judgements, results suggest that the decision to rotate the shoulders is not scaled in the same way as adults, with children showing a critical ratio of 1.61. Shoulder angle at the door could be predicted, for larger aperture ratios, by both shoulder angle variability and lateral trunk variability. This finding supports the dynamical scaling model (Snapp-Childs and Bingham in Exp Brain Res 198:527-533, 2009). In terms of movement adaptations, we have shown that children, like adults, spatially and temporally tailor their movements to aperture size.
Deconinck, F. J. a, Savelsbergh, G. J. P., De Clercq, D., & Lenoir, M. (2010). Balance problems during obstacle crossing in children with evelopmental Coordination Disorder. Gait & posture, 32(3), 327–31.
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 DCD group have a reduced ability to control the momentum of the COM when crossing obstacles that impose increased balance demands.
Hayhoe, M., & Ballard, D. (2005). Eye movements in natural behavior. Trends in cognitive sciences, 9(4), 188–94. doi:10.1016/j.tics.2005.02.009
Ingram, J. N., & Wolpert, D. M. (2011). Naturalistic approaches to sensorimotor control. Progress in brain research, 191, 3–29.
Michel, J., Grobet, C., Dietz, V., & Van Hedel, H. J. a. (2010). Obstacle stepping in children: task acquisition and performance. Gait & posture, 31(3), 341–6.
The aim of this study was to investigate the locomotor capacity of children during the performance of different lower extremity tasks with increasing difficulty. Two subject groups of children (aged 6-8 and 9-12 years) and adult controls performed several motor tasks from the Zürich Neuromotor Assessment (ZNA) test, as well as a unilateral and bilateral obstacle stepping test during treadmill walking. Performance of ZNA items, changes in foot clearance, and obstacle hits were assessed. Correlations between children's age, ZNA and obstacle measures were calculated. Performance of all motor tasks improved with increasing age. All three groups improved foot clearance during unilateral obstacle stepping, while the younger children achieved a poorer performance level. During bilateral obstacle stepping, only the adult controls and the 9-12 years old children's group further improved foot clearance, while no further improvement occurred in the 6-8 years old children's group. A relationship between items of ZNA and bilateral obstacle stepping was found. It is concluded that children in the mid-childhood range are able to significantly improve performance of a high-precision locomotor task. However, children below 9 years of age have a poorer motor performance compared to older children and adults that becomes more pronounced with increasing complexity of the task. Finally, ZNA tests can improve the prediction of complex adaptive locomotor behaviour compared to calendar age alone.
M Nardini & D Cowie (2012). The development of multisensory balance, locomotion, orientation and navigation. In Multisensory Development, A Bremner, D Lewkowicz & C Spence (Eds), Oxford University Press. PDF
See also Marko Nardini's lab page
Rhea, C. K., Rietdyk, S., & Haddad, J. M. (2010). Locomotor adaptation versus perceptual adaptation when stepping over an obstacle with a height illusion. PloS one, 5(7), e11544. PDF
During locomotion, vision is used to perceive environmental obstacles that could potentially threaten stability; locomotor action is then modified to avoid these obstacles. Various factors such as lighting and texture can make these environmental obstacles appear larger or smaller than their actual size. It is unclear if gait is adapted based on the actual or perceived height of these environmental obstacles. The purposes of this study were to determine if visually guided action is scaled to visual perception, and to determine if task experience influenced how action is scaled to perception.
Wilmut, K., & Barnett, A. L. (2011). Locomotor behaviour of children while navigating through apertures. Experimental brain research. 210(2), 185–94. k.wilmut@brookes.ac.uk
During everyday locomotion, we encounter a range of obstacles requiring specific motor responses; a narrow aperture which forces us to rotate our shoulders in order to pass through is one example. In adults, the decision to rotate their shoulders is body scaled (Warren and Whang in J Exp Psychol Hum Percept Perform 13:371-383, 1987), and the movement through is temporally and spatially tailored to the aperture size (Higuchi et al. in Exp Brain Res 175:50-59, 2006; Wilmut and Barnett in Hum Mov Sci 29:289-298, 2010). The aim of the current study was to determine how 8-to 10-year-old children make action judgements and movement adaptations while passing through a series of five aperture sizes which were scaled to body size (0.9, 1.1, 1.3, 1.5 and 1.7 times shoulder width). Spatial and temporal characteristics of movement speed and shoulder rotation were collected over the initial approach phase and while crossing the doorway threshold. In terms of making action judgements, results suggest that the decision to rotate the shoulders is not scaled in the same way as adults, with children showing a critical ratio of 1.61. Shoulder angle at the door could be predicted, for larger aperture ratios, by both shoulder angle variability and lateral trunk variability. This finding supports the dynamical scaling model (Snapp-Childs and Bingham in Exp Brain Res 198:527-533, 2009). In terms of movement adaptations, we have shown that children, like adults, spatially and temporally tailor their movements to aperture size.