Far from the walking pace. Ecological and evolutionary consequences of the suboptimal locomotion speeds in non-adult humans

Introduction

Locomotion activities are part of most human daily tasks and are the basis for subsistence activities, particularly for hunter–gatherers. Therefore, differences in speed walking-related variables may have an effect, not only on the mobility of the group, but also on its composition. Some anthropometric parameters related to body length could affect walking speed-related variables and contribute to different human behaviors. However, there is currently little information on the influence of these parameters in nonadult individuals.

Methods

Overall, 11 females and 17 male child/adolescents, 8–17 years of age, volunteered to participate in this cross-sectional study. Five different pace walking tests were performed on a treadmill to calculate the optimal locomotion speed (OLS) and U-shaped relationship between the walking energy expenditure and speed (χ² cost of transport [CoT]) (i.e., energetic walking flexibility).

Results

The mean OLS was 3.05 ± 0.13 miles per hour (mph), with no differences between sexes. Similarly, there were no sex differences in walking flexibility according to the χ² CoT. Body height (p < .0001) and femur length (p < .001) were positively correlated with χ² CoT; however, female child/adolescents mitigated the effect of height and femur length when walking at suboptimal speeds.

Conclusion

Consistent with prior observations in adults, our findings suggest that anthropometric parameters related to body stature are associated with reduced suboptimal walking flexibility in children and adolescents. Taken together, these results suggest that children and adolescents can adapt their pace to the one of taller individuals without a highly energetic penalty, but this flexibility decreases with increasing body size.