How do you learn to walk? Thousands of steps and dozens of falls per day

Abstract

A century of research on the development of walking has examined periodic gait over a straight, uniform path. The current study provides the first corpus of natural infant locomotion derived from spontaneous activity during free play. Locomotor experience was immense: Twelve- to 19-month-olds averaged 2,368 steps and 17 falls per hour. Novice walkers traveled farther faster than expert crawlers, but had comparable fall rates, which suggests that increased efficiency without increased cost motivates expert crawlers to transition to walking. After walking onset, natural locomotion improved dramatically: Infants took more steps, traveled farther distances, and fell less. Walking was distributed in short bouts with variable paths--frequently too short or irregular to qualify as periodic gait. Nonetheless, measures of periodic gait and of natural locomotion were correlated, which indicates that better walkers spontaneously walk more and fall less. Immense amounts of time-distributed, variable practice constitute the natural practice regimen for learning to walk.

Figure 1

(A) Frequency histogram of walking age across the entire sample. Striped bars denote girls. Gray bars denote home observations. (B) Table on the left of the figure shows mean test age, N, and length of observations. Bars to the right of the figure show distribution of crawling/walking age for each test age. Each vertical line represents one infant. Gray bar denotes home observations.

Figure 2

(A) Layout of the laboratory playroom. Large rectangle on the left shows the gait carpet and one representative walking path. Dimensions are drawn to scale. The playroom also contained a couch, padded square pedestal, slide and small stairs, narrow catwalk behind a wooden barrier, large steps at ends of the catwalk, set of carpeted stairs, set of wooden stairs, a standing activity table, and a wall lined with shelves of toys. (B) Line superimposed over diagram shows the natural walking path of one typical 13-month-old during the first 10 minutes of spontaneous play. Overlapping lines indicate revisits to the same location. Filled circles represent the location of rest periods longer than 5 sec; open circles denote falls.

Figure 3

Comparisons between 12-month-old expert crawlers and novice walkers: (A) falls/hour, (B) proportion of time in motion, (C) steps/hour, (D) distance/hour, (E) time in motion before each fall, (F) steps before each fall, (G) distance traveled before each fall. Solid lines on box plots denote medians and dashed lines denote means; circles denote outliers beyond the 5^th and 95^th percentiles.