The Development of Walking Skill: Effects of Contextual Factors, Skill Onset Ages, and Locomotor Practice

• In Event: Novel Findings and New Methods in Motor Skill Development, Perception, & Learning

Abstract

Infant walking skill improves with practice: Over weeks of walking, infants take faster, longer, narrower steps compared to their short, staccato steps as novice walkers. But despite the robustness of the relation between practice and skill, behavior is also constrained and facilitated by contextual factors, such as social and cultural influences, the physical environment in which infants are raised, and the current status of infants’ bodies. Accordingly, motor pathways are tremendously diverse, in terms of the timing of walk onset, the practice accrued, and the trajectory of improvement. So, what affects the development of walking skill?

We examined the role of contextual factors, onset ages, and walking practice (days of walking and real-time spontaneous walking) on the development of walking skill in two samples of 13-, 15-, and 19-month-old infants, with sample-specific differences in demographic and environmental factors (Figure 1). The “Bellevue hospital” sample (n=38) was largely Hispanic infants with less formally educated caregivers. The “Langone hospital” sample (n=44) was largely non-Hispanic, White infants with formally educated caregivers. We determined infants’ crawl and walk onset ages from parent report and laboratory observations. We recorded infants’ locomotor activity during 20 minutes of free play with their caregiver in a laboratory playroom and calculated the percent of the session infants spent walking, step rate (steps per walking minute), and percent of short bouts (1-3 steps). We measured infants’ step length and step width with a pressure-sensitive gait carpet (Figure 2A).

As expected, infants with more days of walking took longer and narrower steps (rs = .67 and -.56, ps < .001; Figure 2B). We conducted a path analysis predicting step length and step width, adjusting for contextual factors (sample membership; people/room and accessible park land; infant height percentile and weight-for-height percentile), crawl and walk onset ages, days of walking, and locomotor activity (percent time walking, step rate, percent short bouts; Figure 2C). As in previous work, days of walking was the strongest predictor of walking skill, with rapid improvements in the first 3.9 months for step length and 2.5 months for step width, and slower improvements past those knots. However, even after adjusting for days of walking, infants from homes with fewer people/room displayed better walking skill, as did infants with a smaller percent of short walking bouts. Despite sample differences in crawl and walk onset ages (Figure 1A)—Bellevue infants (Ms = 9.5 and 13.6 months) crawled and walked later than did Langone infants (Ms = 8.1 and 12.4 months; ts> 3.14, ps < .002)—onset ages did not affect the development of walking skill. Neither did sample membership, park space, body factors, percent of time spent walking, or step rate. In sum, days of walking best predicted how well infants walked, but less crowded homes and a smaller percent of short walking bouts also predicted more mature walking skill. These findings suggest that although the developmental processes associated with the development of walking skill are robust, they are nonetheless affected by contextual factors and real-time activity.

Authors

• Christina Hospodar, New York University
  Presenting Author

• Justine Hoch, New York University
  Non-Presenting Author

• Do Kyeong Lee, New York University
  Non-Presenting Author

• Patrick Shrout, New York University
  Non-Presenting Author

• Karen E Adolph, New York University
  Non-Presenting Author