The effect of carried loads on the walking patterns of men and women

Abstract

In order to determine the effect of loads worn or carried on walking mechanics, 11 men and 11 women were filmed using high speed cinematography as they performed overground walking at 1·78 m/s under five load conditions. The loads included a baseline condition in which subjects carried no added load, and additional loads of approximately 9, 17, 29 and 36 kg consisting of standard military items. The latter two loads were added in the form of a framed rucksack system. Values for several variables frequently used to described temporal and kinematic characteristics of walking were quantified from the film. These included stride length, stride rate, single leg support time, double-support time, swing time and the forward inclination of the trunk. The results of the study demonstrated that the males and females displayed significantly different gait patterns under all load conditions. Not unexpectedly, the females required a higher rate of stepping than the males because of their shorter stride lengths. The results also demonstrated that the walking patterns of both the male and female subjects were affected by the increases in carried load. In general, stride length and swing time decreased while stride rate and double-support time increased with increases in load. There was also an increased forward inclination of the trunk but only for the two heaviest loads which were carried in a rucksack. While the changes in gait characteristics were relatively small for the male subjects, the females were affected to a greater extent thereby demonstrating a greater sensitivity to load magnitude. It was concluded that careful consideration must be given to the absolute loads carried by males and females. Not only is it important for load requirements to be lower for females because of the physiological implications but also because of biomechanical implications and the associated mechanical stresses which must be endured during locomotion. While this study was directed primarily towards military applications, the results should also have implications for load carrying in a variety of situations and environments, including industrial and recreational applications.