Lower limb muscle activity underlying temporal gait asymmetry post-stroke

Area of Science:

• Neuroscience
• Biomechanics
• Rehabilitation Medicine

Background:

• Asymmetric walking (temporal gait asymmetry or TGA) is a frequent and debilitating consequence of stroke.
• Limited understanding of the underlying physiological mechanisms hinders effective treatment of TGA.

Purpose of the Study:

• To investigate the electromyographic (EMG) features associated with temporal gait asymmetry (TGA) after stroke.
• To characterize the neuromuscular underpinnings of spatiotemporal gait deviations in stroke survivors.

Main Methods:

• Collected electromyography (EMG), force plate, and motion capture data during self-paced overground walking.
• Compared lower limb muscle activity patterns across three groups: stroke survivors with TGA, stroke survivors without TGA, and neurologically healthy controls.
• Analyzed muscle activation timing and patterns relative to gait phases and limb affectedness.

Main Results:

• Stroke survivors with TGA showed significantly earlier termination of plantarflexor activity in the more affected limb during stance.
• Delayed onset and offset of dorsiflexor activity were observed in the less affected limb of individuals with TGA.
• The TGA group exhibited a reduced number of dorsiflexor bursts during the swing phase compared to controls.

Conclusions:

• Specific temporal patterns of muscle activation around the ankle, particularly during the stance-to-swing transition, are associated with TGA post-stroke.
• These findings suggest distinct neuromuscular impairments or compensatory strategies contributing to locomotor dysfunction and asymmetry.
• This research provides novel insights that could inform the development of targeted therapies to enhance gait quality and coordination after stroke.