If you and a taller friend walk the same distance at the same speed, who will use more energy? According to a just-published study in the Journal of Experimental Biology, you will, at least on a per pound basis. Shorter people expend more calories on a per weight basis than their more gangly walking companions.
The study took 48 individuals ranging between 5 - 32 years old, 15.9 - 88.7 kg, and 1.07 m (3'6") to 1.83 m (6'0") and measured their metabolic rates and gait mechanics at six different speeds. What they discovered was that the metabolic cost of each stride was identical, regardless of height. Therefore, taller people walk more economically because they take fewer strides than shorter people to cover the same ground.
Note, however, that energy expenditure is measured on a per kilogram basis—not on a total calories required basis. So shorter people don't necessarily use more total calories than tall people when walking, they just require more calories per unit weight than their taller brethren. Additionally, the efficiency increase was directly proportional to the change in stature (e.g., a 2-meter tall person walks twice as economically as a 1-meter person). Now you know why young children tire so easily on a hike!
Interestingly, another finding of the study was that shorter and taller people have the identical gait mechanics, regardless of height. If you transformed a 3-foot tall child into a 7-foot tall mega-kid, the stride mechanics would still be the same.
Here's a short summary of the study, or you can read the full article here.
“Equipped” is an AMC Outdoors blog, written by Matt Heid.