Do gait and muscle activation patterns change at middle-age during split-belt adaptation?

Area of Science:

• Biomechanics
• Neuroscience
• Human Movement Science

Background:

• Advancing age impacts gait adaptability, but its effect on middle-aged individuals during split-belt walking is not fully understood.
• Neuromuscular control changes potentially begin in middle age, influencing gait adaptation.
• Investigating middle-aged adults is crucial for understanding the trajectory of age-related gait changes.

Purpose of the Study:

• To examine the effects of age on gait and muscle activation pattern adaptations during split-belt walking.
• To compare gait adaptability in healthy young and middle-aged adults.
• To determine if neuromuscular control changes in middle age affect gait adaptation to split-belt perturbations.

Main Methods:

• Healthy young (23.3 ± 3.13 years) and middle-aged (55.3 ± 2.91 years) adults walked on an instrumented split-belt treadmill.
• Surface electromyography (EMG) was recorded from eight leg muscles bilaterally.
• Principal Component Analysis (PCA) and Statistical Parametric Mapping (SPM) were used to analyze muscle activation patterns.

Main Results:

• Both young and middle-aged adults demonstrated similar adaptations in reducing gait asymmetry (step length, double support time).
• Functional muscle groups, identified via PCA, showed similar increases and decreases in activation over time during adaptation in both age groups.
• Extra activation peaks in plantar- and dorsiflexors were observed, suggesting a role in gait modulation.

Conclusions:

• Split-belt gait adaptation, including gait symmetry and muscle activation patterns, is preserved in middle-aged adults.
• The adaptation of muscle activation patterns parallels gait symmetry adaptation, indicating muscle activity underlies gait adjustments.
• Age-related differences in split-belt gait adaptation likely manifest later in the lifespan.