Citation

Rabin E, Shi P, Werner WG. J. Neurophysiol. 2016; 115(6): 2880-2892.

Affiliation

New York Institute of Technology.

Copyright

(Copyright © 2016, American Physiological Society)

DOI

10.1152/jn.00670.2015

PMID

26936979

Abstract

We investigated the timing of gait parameter changes(stride length, peak toe velocity, and double-, single-support and complete step duration) to control gait speed. Eleven healthy participants adjusted their gait speed on a treadmill to maintain a constant distance between them and a fore-aft oscillating cue (a place on a conveyor belt surface). The experimental design balanced conditions of: cue modality (vision: eyes-open, manual contact: eyes-closed while touching the cue); treadmill speed (0.2, 0.4, 0.85, 1.3m/s); and cue motion (none, ±10cm at 0.09Hz, 0.11Hz and 0.18 Hz). Correlation analyses revealed different gait parameters were controlled with various temporal relationships to the cue speed: step length anticipated its most-correlated cue velocity during the subsequent double-support; peak toe velocity nearly coincided with its most-correlated cue velocity during single-support; and the toe-off concluding step- and double-support durations followed cue velocity. Cue-tracking accuracy and cue velocity correlations with timing parameters were higher with the manual contact cue than visual cue. The cue/ gait timing relationships generalized across cue modalities, albeit with greater delays of step-cycle events relative to manual contact cue velocity. We conclude: Individual kinematic parameters of gait are controlled to achieve a desired velocity at different specific times during the gait cycle. The overall timing pattern of instantaneous cue velocities associated with different gait parameters is conserved across cues. This timing pattern may be temporally shifted to optimize control. Different cue/ gait parameter latencies in our non-adaptation paradigm provides general-case evidence of the independent control of gait parameters previously demonstrated in gait adaptation paradigms.

Language: en