Myoelectric Activation Pattern Changes in the Involved Limb of Individuals With Transtibial Amputation During Locomotor State Transitions.

OBJECTIVE

To 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 is hypothesized that all transitions elicit activation differences between strides as the subjects move toward the transition event.

DESIGN

Single-sample, observational study.

SETTING

University research center.

PARTICIPANTS

Volunteer sample of persons with unilateral transtibial amputation (N=9; mean age, 48.8±12.1y; mean height, 1.74±0.09m; mean weight, 86.1±24.7kg) were recruited by posting flyers in local prosthetics clinics.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Surface electromyography was used to measure muscle activation from 7 muscles of the involved limb. Subjects walked across 8 different terrain conditions transitioning from level-ground to ramp/stair locomotion and vice versa. Statistical Parametric Mapping analysis of variance (α<.05) was used to assess muscle activation differences in the 3 pretransition gait cycles as subjects moved toward the terrain change.

RESULTS

No muscle activation changes were observed in ramp transitions. All stair transitions elicited a myoelectric difference in at least 2 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.

CONCLUSIONS

Muscle 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 pretransition using electromyography.