'Institute of Electrical and Electronics Engineers (IEEE)'
Doi
Abstract
Motor control strategies can be described by
muscle synergies, a model of functional muscle recruitment to
perform a movement. However, stability of muscle synergies
during locomotion has not yet been investigated. The objective of
this work was the evaluation of the stability of muscle synergies
while walking at normal (NS) and fast (FS) speed. Each walking
condition was tested during a prolonged session lasting 5 minutes
on five healthy subjects. After data processing with statistical gait
analysis, 168±29 valid strides in NS and 181±48 in FS were
obtained. They were aggregated in subgroups, with 10 strides
each. Muscle synergies were extracted for all subgroups with
non-negative matrix factorization. On the average, 6 synergies
were suitable to reconstruct the original electromyographic
signal. They were functionally correlated to the activities of
propulsion, trunk stability, limb deceleration at the end of swing,
forefoot control, and limb stiffening for initial contact stability.
To compare muscle synergy stability over time, a similarity
measurement was carried out. This showed that from 1 to 3
synergies were unstable in NS. As for the FS condition, only one
subject showed unstable synergies, corresponding to the hip
stabilizing synergy