Kinematics in newly walking toddlers does not depend upon postural stability

Area of Science:

• Developmental biology
• Biomechanics
• Motor control

Background:

• Toddler gait exhibits distinct kinematic and electromyographic (EMG) patterns compared to older children, characterized by body oscillations due to poor equilibrium.
• While postural instability impacts adult motor patterns, its specific role in explaining unique toddler gait remains unclear.

Purpose of the Study:

• To investigate whether postural instability explains the distinct gait patterns observed in toddlers during their first independent steps.
• To compare gait kinematics and EMG activity in toddlers with and without hand or trunk support.

Main Methods:

• Comparison of gait kinematics and electromyography (EMG) in toddlers taking their first unsupported steps.
• Inclusion of conditions with and without hand or trunk support to assess the impact on stability and gait parameters.

Main Results:

• Hand support improved postural stability and some gait parameters (reduced falls, step width, hip deviations, trunk oscillations).
• Key kinematic and EMG patterns (lower limb segment motion, hip coordination, foot path variability, EMG bursts) remained unchanged despite improved stability.
• Toddler gait shares features with adult 'stepping in place,' suggesting a mixed locomotor strategy.

Conclusions:

• The idiosyncratic features of toddler gait are not solely due to underdeveloped balance control.
• These features may represent an innate kinematic template for stepping, which matures rapidly after the first unsupported steps.