Kinematic variability and relationships characterizing the development of walking

Area of Science:

• Developmental biomechanics
• Motor control
• Human locomotion

Background:

• Understanding the developmental trajectory of walking is crucial for identifying typical and atypical motor patterns.
• Early walking involves significant variability in joint kinematics, but the underlying coordination strategies are not fully understood.

Purpose of the Study:

• To investigate the variability and inter-joint relationships in hip, knee, and ankle kinematics during the development of walking.
• To examine if providing postural support to new walkers reduces kinematic variability.

Main Methods:

• Measured joint kinematics (hip, knee, ankle) over 10 gait cycles in new walkers, supported new walkers, 2-year-olds, and 7-year-olds.
• Utilized Fourier series analysis to characterize joint motions and compared standard deviations across age groups.
• Assessed correlations between joint rotations (hip-knee, knee-ankle, hip-knee).

Main Results:

• Observed an age-related decrease in kinematic variability in specific phases of the gait cycle.
• Found significant correlations between stance/swing phase duration and overall cycle duration across all age groups.
• Postural support did not significantly reduce joint rotation variability in new walkers.
• Demonstrated strong cross-correlations between hip-knee, knee-ankle, and hip-knee rotations in all participants.

Conclusions:

• A fundamental coordinative structure for walking emerges early in development, characterized by strong intralimb coupling.
• Despite observable variability in certain joint movements during early walking, the basic pattern of inter-joint coordination is established.
• Postural support does not appear to alter the intrinsic variability of joint kinematics during initial walking development.