Foot Placement Characteristics and Plantar Pressure Distribution Patterns during Stepping on Ground in Neonates

Area of Science:

• Developmental neuroscience
• Biomechanics
• Motor control

Background:

• Neonatal stepping is irregular, lacking adult-like heel-to-toe patterns.
• Understanding early foot placement is crucial for insights into locomotion development.
• Detailed characteristics of infant foot placement and motor associations are not fully documented.

Purpose of the Study:

• To investigate the characteristics of foot placements in neonates.
• To analyze the association between foot placement and motor patterns during stepping.
• To explore the role of proprioceptive feedback in early locomotion.

Main Methods:

• Elicited stepping in 33 neonates supported on a table.
• Recorded unilateral limb kinematics, bilateral plantar pressure, and EMG from leg muscles.
• Analyzed foot placement variations, initial contact types, and associated kinematic/loading patterns.

Main Results:

• Neonatal foot placements varied widely, with ~25% of steps overlapping the contralateral foot.
• Stance phase initiation included forefoot (28%), midfoot (47%), or heel (25%) touchdowns.
• Initial foot contact correlated with specific center-of-pressure, ankle ROM, and extensor muscle activity patterns.

Conclusions:

• Neonatal stepping displays diverse footfall patterns linked to distinct motor responses.
• Findings suggest the involvement of load-related proprioceptive feedback in early human stepping.
• Variations in the locomotor program may be present even in the earliest stages of infant stepping.