The development of gait and mobility: Form and function in infant locomotion

Abstract

The development of locomotion can be described by its form (i.e., gait) and its function (i.e., mobility). Both aspects of locomotion improve with experience. Traditional treatises on infant locomotion focus on form by describing an orderly progression of postural and locomotor milestones en route to characteristic patterns of crawling and walking gait. We provide a traditional treatment of gait by describing developmental antecedents of and improvements in characteristic gait patterns, but we highlight important misconceptions inherent in the notion of "milestones". Most critically, we argue that the prevailing focus on gait and milestones fails to capture the true essence of locomotion-functional mobility to engage with the world. Thus, we also describe the development of mobility, including the use of mobility aids for support and propulsion. We illustrate how infants find individual solutions for mobility and how the ability to move cascades into other domains of development. Finally, we show how an integration of gait and mobility provides insights into the psychological processes that make locomotion functional. This article is categorized under: Psychology > Motor Skill and Performance Psychology > Development and Aging.

Keywords: development; gait; locomotion; mobility; walking.

Figure 1.

Gait versus mobility. (A) Typical “straight-path” task to measure gait patterns: Infants walk on a pressure-sensitive gait mat that records the timing and placement of each step (footprints on large rectangle from one trial). Caregivers at the end of the path encourage infants to walk toward them. Inset shows characteristic gait patterns from novice and experienced infant walkers. (B) Free-play task to measure mobility: Infants spontaneously move throughout the room, occasionally walking on the gait mat. Infants generate walking bouts of all lengths and path shapes (footprints on large rectangle, dotted lines elsewhere; filled black circles show stops between bouts from a few minutes of spontaneous walking). Steps on the mat in bouts of sufficient length allow opportunistic measures of gait patterns. Steps everywhere in the room in bouts of any length allow measures of mobility.

Figure 2.

Gait modifications required for functional mobility. (A) Infant walking on an adjustable slope apparatus to measure perception of affordances. Flat starting and landing platforms flank an adjustable sloping middle section (0–90° in 1° increments). Infants begin each trial standing on the starting platform and must decide whether and how to descend. An experimenter follows alongside infants to ensure their safety. Caregivers at the far end encourage infants to walk using toys and snacks as enticements. (B) Gait modifications: Footprints show characteristic gait patterns of an experienced walking infant while approaching (first rectangle) and descending (second rectangle) a shallow slope (top panel) and steep slope (bottom panel). On the shallow slope, long, regularly spaced steps show no gait modifications. On the steep slope, decrease in step length and cluster of footprints at the brink show gait modifications during approach, and small, overlapping steps on the slope show gait modifications during descent.