Tuning of Muscle Synergies During Walking Along Rectilinear and Curvilinear Trajectories in Humans

Abstract

The aim of this study was to develop a methodology based on muscle synergies to investigate whether rectilinear and curvilinear walking shared the same neuro-motor organization, and how this organization was fine-tuned by the walking condition. Thirteen healthy subjects walked on rectilinear and curvilinear paths. Electromyographic data from thirteen back and lower-limb muscles were acquired, together with kinematic data using inertial sensors. Four macroscopically invariant muscle synergies, extracted through non-negative matrix factorization, proved a shared modular organization across conditions. The fine-tuning of muscle synergies was studied through non-negative matrix reconstruction, applied by fixing muscle weights or activation profiles to those of the rectilinear condition. The activation profiles tended to be recruited for a longer period and with a larger amplitude during curvilinear walking. The muscles of the posterior side of the lower limb were those mainly influenced by the fine-tuning, with the muscles inside the rotation path being more active than the outer muscles. This study shows that rectilinear and curvilinear walking share a unique motor command. However, a fine-tuning in muscle synergies is introduced during curvilinear conditions, adapting the kinematic strategy to the new biomechanical needs.

Neuromuscular control during gait in people with haemophilic arthropathy

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“…In the control group (CG), the dominant limb was assessed, which was determined by asking the subjects which leg they would use to kick a ball. 22 After shaving and cleaning the skin with alcohol, surface electrodes (Ag-AgCl, Kendall H124SG) were placed (interelectrode spacing 2 cm) on the following muscles according to SENIAM guidelines 23…”

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“…A muscle synergy is a functional group of muscles simultaneously contracting during a motor task [13]. Muscle synergy analysis has been applied both in healthy controls and neurological patients for different motor tasks, especially for walking [6,15,16].…”

Investigation of the Intra- and Inter-Limb Muscle Coordination of Hands-and-Knees Crawling in Human Adults by Means of Muscle Synergy Analysis

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“…Tang et al compared the gait muscle synergies of cerebral palsy (CP) children, and typically developed children and adults, and found that the abnormalities of muscle synergy in CP children could reflect their motor dysfunction and even the physiological change in their nervous system [18]. Chia et al found that rectilinear walking and curvilinear walking shared the same muscle synergies, but a fine-tuning in muscle synergies was introduced during curvilinear conditions, adapting the kinematic strategy to the new biomechanical needs [19].…”