Faculty Advisor
Marcella Myers
Department
Biology
Abstract
Despite the necessity of toddler-carrying by adults, little research has focused on the energetic and behavioral consequences of this activity.
PURPOSE: To determine whether women and men carrying a toddler-sized manikin on their hip or shoulders choose different stride frequencies at a given speed when asked to walk around the perimeter of a gym at moderate to brisk free walking speeds.
METHODS: We calculated the walking speed of 6 females and 6 males as they walked the perimeter of a gym while performing 6 randomly ordered tasks. Tasks consisted of all combinations of 3 loading conditions (10kg toddler manikin carried on shoulders or hip, or a 10kg waist belt) and 2 walking speed directives (“walk-all-day”, “brisk walk”). Stride frequency and walking speed were determined from videotape.
RESULTS: At a given speed directive, females walked faster than males (p=0.001); body mass could not explain sex difference in walking speed). At a given walking speed, females used higher stride frequencies than males (p<0.001) and stride frequency increased as load position changed from belt, to shoulder, to hip (p=0.006). Adding body mass to the model removed the sex effect.
CONCLUSIONS: Although the carrying task was a larger burden for the females due to their smaller body mass, females consistently chose faster walking speeds than males for a given speed directive, and higher stride frequencies for a given walking speed. Sex differences appeared to be the result of differences in the size of the toddler load relative to body mass.
Funding source, if applicable
3M Faculty/Student Collaborative Grant
Start Date
19-4-2012 11:00 AM
End Date
19-4-2012 1:00 PM
Sex Differences in the Stride Frequency of Walking while Carrying a Toddler Manikin
Despite the necessity of toddler-carrying by adults, little research has focused on the energetic and behavioral consequences of this activity.
PURPOSE: To determine whether women and men carrying a toddler-sized manikin on their hip or shoulders choose different stride frequencies at a given speed when asked to walk around the perimeter of a gym at moderate to brisk free walking speeds.
METHODS: We calculated the walking speed of 6 females and 6 males as they walked the perimeter of a gym while performing 6 randomly ordered tasks. Tasks consisted of all combinations of 3 loading conditions (10kg toddler manikin carried on shoulders or hip, or a 10kg waist belt) and 2 walking speed directives (“walk-all-day”, “brisk walk”). Stride frequency and walking speed were determined from videotape.
RESULTS: At a given speed directive, females walked faster than males (p=0.001); body mass could not explain sex difference in walking speed). At a given walking speed, females used higher stride frequencies than males (p<0.001) and stride frequency increased as load position changed from belt, to shoulder, to hip (p=0.006). Adding body mass to the model removed the sex effect.
CONCLUSIONS: Although the carrying task was a larger burden for the females due to their smaller body mass, females consistently chose faster walking speeds than males for a given speed directive, and higher stride frequencies for a given walking speed. Sex differences appeared to be the result of differences in the size of the toddler load relative to body mass.
Comments
Keywords:
stride frequency, metabolic cost, loads, carrying, gender differences, body size, position, stride length, walking speed choice, shoulder load, hip load, belt load, toddler