Influence of Additional Ankle Weights on Kinematic Variables of Late Preterm Infants Aged 3-4 Months

Area of Science:

• Developmental Pediatrics
• Motor Control
• Infant Biomechanics

Background:

• Understanding infant motor development is crucial for identifying potential developmental differences.
• Spatiotemporal parameters of movement provide objective measures of motor control.
• The impact of external loads on infant kicking mechanics is not well-understood.

Purpose of the Study:

• To compare the effects of added weight on kicking spatiotemporal parameters in late preterm and full-term infants.
• To investigate motor adaptations in response to external loads during infant kicking.
• To assess recovery of kicking patterns after load removal.

Main Methods:

• Infants (late preterm and full-term) performed kicking movements under four conditions: training, baseline, added weight, and post-weight.
• A weight equivalent to one-third of the lower limb mass was applied to the ankle during the weight condition.
• Spatiotemporal parameters, including the straightness index and joint correlations, were analyzed.

Main Results:

• No significant differences in spatiotemporal variables were observed between late preterm and full-term infants at 3 and 4 months in baseline conditions.
• Added weight significantly decreased the straightness index and hip-ankle/knee-ankle correlations in preterm infants.
• The straightness index improved in the post-weight condition compared to baseline for both infant groups.

Conclusions:

• Late preterm and full-term infants exhibit similar baseline kicking kinematics.
• External loads impact the motor control of kicking in preterm infants more significantly than in full-term infants.
• Infants demonstrate adaptive motor responses following the removal of external loads, suggesting motor plasticity.