Asymmetrical motor behaviour as a window to early leg preference: a longitudinal study in infants 7–12 months of age

ABSTRACT

This longitudinal study explored leg preference in infancy during half-kneel pulling-to-stand (PTS) and asymmetrical four-point kneeling, which is part of the typical motor repertoire of infants. The special characteristics of the half-kneel PTS as a discrete task, performed in a bilateral context provide the opportunity to explore leg preference during an asymmetrical behaviour. Twenty-seven infants were observed in their homes, every 3 weeks between the ages of 7–12 months. Leg preference was determined by the “lead-out” limb used as the infants pulled to stand from the half-kneeling position (half-kneel PTS). As a complementary measure, the leading leg during asymmetrical four-point kneeling and crawling (“asymmetrical four-point patterns”) was used in the 10 infants who developed these patterns. The infants studied showed a general preference for using a leading leg during half-kneel PTS, which was mostly consistent over the study period. A strong correlation was found between leg preferences during half-kneel PTS and asymmetrical four-point patterns. The findings documented functional asymmetry in infant lower limbs during half-kneel PTS and asymmetrical four-point patterns, highlighting the importance of the tasks used to define leg preference.

KEYWORDS:

• Leg preference
• lateralization
• developmental trajectory
• pulling to stand
• infancy
• asymmetrical task

Acknowledgements

This article is based on data collected by Osnat Atun-Einy in partial fulfilment of a doctoral dissertation, supervised by Prof. Anat Scher, Department of Counseling and Human Development, University of Haifa. We gratefully acknowledge Moran Samuel for assistance with data collection and coding; Sandra Zuckerman for data management and analysis; and all the infants and their families for their enthusiasm for and commitment to participating in this research study.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

The research was supported by Israel Science Foundation [grant number 208/07] to Anat Scher.