At their own pace: Optimal walking speed in children and adolescents

Abstract

Objectives: An important factor for human walking behavior is the speed at which an individual—adult or non-adult—is able to move at a minimum energetic cost. Our aim was to assess the extent to which juveniles walking with adults force the group to set a pace that is energetically too costly for adults by comparing the optimal walking speed of juveniles and adults. Materials and methods: An experimental study was carried out indoors in a sample of 74 children and adolescents of both sexes, between 7 and 14 years of age. Volunteers walked on a treadmill at six different speeds, and the gross cost of transport (CoT), minimum gross energy cost (minCoT), and optimal locomotion speed (OLS) were determined for each individual. These values were compared with the optimal values for adults, as reported in the literature. Results: Our results show that OLS is similar in boys and girls, and that there are no sex differences in minCoT. Older individuals, as a consequence of their larger size, spend more energy at their optimal speed than younger children. Discussion: Juveniles are not a real burden for the rest of the group in foraging societies, neither in energetic terms nor in locomotor efficiency, being able to achieve optimal walking speeds similar to adults. The so-called energetic dilemma for sex-mixed walking groups does not affect juveniles when moving together with adults or in sex-mixed parties.