Related Experiment Video
Updated: Mar 9, 2026
Quantifying Learning in Young Infants: Tracking Leg Actions During a Discovery-learning Task
Published on: June 1, 2015
Influence of Different Sitting Positions on Healthy Infants' Reaching Movements
Erika Shirley Moreira da Silva1, Gabriela Lopes Dos Santos2, Ana Luiza Righetto Greco1
1a Department of Physiotherapy , Federal University of São Carlos , São Carlos , Brazil.
Insights
Infant reaching performance is affected by sitting position at 6 months but not 7 months. Greater trunk control consistently improves reaching skills in infants.
Area of Science:
- Developmental psychology
- Motor control in infants
- Infant biomechanics
Background:
- Infant reaching is a fundamental motor skill crucial for development.
- Trunk control significantly impacts upper limb movements.
- Understanding how posture affects reaching informs developmental assessments.
Purpose of the Study:
- To investigate the effect of sitting positions (ring and flexion) on reaching performance in 6- and 7-month-old infants.
- To correlate trunk control levels with reaching performance.
- To identify age-specific influences of posture on infant reaching.
Main Methods:
- Spatiotemporal variables of reaching were analyzed in full-term infants aged 6 and 7 months.
- Infants were assessed in two sitting positions: ring and flexion.
- Trunk control was measured using the Segmental Assessment of Trunk Control (SATC).
Main Results:
- Sitting position influenced reaching in 6-month-olds, with the ring position yielding better performance in trunk displacement, deceleration time, movement units, straightness index, and mean velocity.
- No significant influence of sitting position on reaching performance was observed in 7-month-old infants.
- A positive correlation was found between higher levels of trunk control and improved reaching performance across all conditions.
Conclusions:
- Sitting posture plays a role in early reaching development, particularly at 6 months.
- Mature trunk control is a key factor for effective reaching, independent of age and posture.
- These findings highlight the importance of trunk stability for developing reaching skills in infants.
Abstract:
The authors analyze the influence of different sitting positions (ring and flexion) on the reaching performance (spatiotemporal variables) of full-term infants 6 and 7 months old. In addition, they correlated level of trunk control, measured by the Segmental Assessment of Trunk Control, with performance during reaching. The different sitting positions only influenced the reaching movements of 6-month-old infants, who showed the best performance in the ring position. However, this influence was observed only for the trunk displacement, deceleration time, movement units, straightness index and mean velocity. In contrast, there was no influence of positions on 7-month-old infants' reaching performance. Regarding the correlations, it was observed that infants with more level of trunk control showed a better performance when reaching, regardless of position and the age assessed.
