Myoelectric activation pattern changes in the involved limb of individuals with transtibial amputation during locomotor state transitions

Publication date: Available online 3 January 2017
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Bryson H. Nakamura, Michael E. Hahn
ObjectiveTo investigate whether lower extremity muscle activation patterns differ in the strides leading to locomotive state transitions in the involved limb of individuals with transtibial amputation. It was hypothesized that all transitions would elicit activation differences between strides as the subjects moved toward the transition event.DesignA single sample, observational study.SettingThe study was conducted in the hallways, ramps and stairs of a university building.ParticipantsA volunteer sample of nine persons with unilateral transtibial amputation (48.8±12.1years; 1.74±0.09m; 86.1±24.7kg) were recruited by posting flyers in local prosthetics clinics.InterventionsNot applicable.Main Outcome MeasuresSurface electromyography was used to measure muscle activation from seven muscles of the involved limb. Subjects walked across eight different terrain conditions transitioning from level-ground to ramp/stair locomotion and vice versa. Statistical Parametric Mapping Analysis of Variance (α<0.05) was used to assess muscle activation differences in the three pre-transition gait cycles as subjects moved toward the terrain change.ResultsNo muscle activation changes were observed in ramp transitions. All stair transitions elicited a myoelectric difference in at least two muscles. The transition from stair descent to level ground elicited change in the greatest number of muscles. Tibialis anterior activation was unchanged in all transitions.ConclusionsMuscle activation differences were observed in the involved limb of individuals with transtibial amputation during stair transitions, suggesting that those patterns may be successfully used in transition detection algorithms. It remains unknown whether ramp transitions can be successfully identified pre-transition using electromyography.



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