Printer-friendly versionSend by emailPDF version
TitleEarly changes in muscle activation patterns of toddlers during walking
Publication TypeJournal Article
Year of Publication2006
AuthorsChang, C. - L., Kubo M., Buzzi U., & Ulrich B. D.
JournalInfant Behavior & Development
Volume29
Issue2
Pagination175 - 188
Date Published2006/04//
ISBN Number1934-8800
KeywordsAnalysis of Variance, Body Size, Electromyography, Female, Functional Laterality, Humans, Infant, Longitudinal Studies, Male, Motor Activity, Multivariate Analysis, Muscle, Skeletal, Parents, Walking
Abstract

Early locomotor behavior has been the focus of considerable attention by developmentalists over several decades. Few studies have addressed explicitly patterns of muscle activity that underlie this coordination pattern. Our purposes were to illustrate a method to determine objectively the onset and offset of muscle firings during early walking and to investigate the emergence of patterns of activation of the core locomotor muscles. We tested eight toddlers as they walked overground at walking onset (max. of 3-6 independent steps) and after three months of walking experience. Surface electrodes monitored activity of the gastrocnemius, tibialis anterior, quadriceps, and hamstrings. We reduced EMG signals to a frame-by-frame designation of "on-off," followed by muscle state and co-contraction analyses, and probability distributions for each muscle's activity across multiple cycles. Our results clearly show that at walking onset muscle activity was highly variable with few, if any, muscles showing recurring patterns of behavior, within or among toddlers. Variability and co-activation decreased with walking experience but remained inconsistent, in contrast to the significant increase in stability shown for joint coordination and endpoint (foot placement) parameters. We propose this trend emerges because of the high number of options (muscle combinations) available. Toddlers learn first to marshal sufficient force to balance and make forward progress but slowly discover how to optimize these resources.

URLhttp://www.ncbi.nlm.nih.gov/pubmed/17138273

Your Kinesiology Connection

Return to top