This is the raw data for an article in the process of being published. The article's abstract is: There is evidence suggesting that during walking the whole body center-of-mass (COM) trajectory may be a control objective, a goal that the central nervous system chooses optimal solutions around to plan and regulate movement. However, the perspective that the nervous system acts to plan and control motion of the whole-body during walking is not the dominant viewpoint. We recently investigated how people adapt to a novel and consistent laterally-directed force field during repetitions of a discrete goal-directed walking task. This study found that participants counteracted the force field by adapting their COM trajectory by forming an internal model. This control strategy was accomplished in a uniform manner across participants all of whom took a wider first step with their right limb (1). Because we observed changes in two variables it is difficult to discern the control objective (was foot placement controlled and the COM trajectory a byproduct, or vise-versa). A stronger test of control objectives during walking would be to vary the force field direction and observe if either the COM trajectory or limb movements remain constant. The purpose of the current study was to investigate if the nervous system controls COM trajectory during a goal-directed walking task in a novel and consistent environment. We created this environment by applying a continuous, laterally-directed (to the left) force field to the COM that was proportional in magnitude to forward walking velocity. We hypothesized that, similar to previous studies of predictable changes in environment (2, 3), people would form an internal model of the COM trajectory, as shown by adaptation of COM signed deviation towards baseline in the force field and see after effects, deviation in the opposite direction of initial COM signed deviation, when the force field is unexpectedly removed. We found that participants did form an internal model, as evidence of adaptation of COM trajectory throughout the force field. However, we also found that participants utilized two separate foot placement strategies, half of the group taking three steps and the other half of the group taking two steps. The observation of a consistent COM trajectory and variable foot placement strategies between participants supports the idea that the COM trajectory may be a control objective of the nervous system during walking.

Last modified

• 08/26/2021

Creator

• Brown, Geoffrey
• Bucklin, Mary
• Gordon, Keith

DOI

• https://doi.org/10.21985/n2-pnrm-kj07

Publisher

• Northwestern University

Date created

• 2021-08-12

Resource type

• Dataset

License

• Open Data Commons Attribution License (ODC-By)

Total Size

• 215 MB