Does posture matter?

There is extensive scientific literature which shows that the way in which a load is carried on the body—for example, the way it is distributed across the trunk and the magnitude of its weight—can have a significant impact on a person’s ability to maintain proper postural balance. Carrying an improperly placed, poorly balanced load or carrying one that is too heavy, can increase a person’s risk of musculoskeletal injury of the lower back by making it more likely they will slip or fall. Such mishaps are especially concerning for individuals working in tactical occupations such as firefighters, police officers, and members of the military who must carry heavy loads and equipment on the job.

Researchers at George Mason University’s School of Kinesiology recently authored a paper on the effects of load carriage on postural stability during quiet standing in young, healthy adults. The paper was based on a meta-analysis of data extracted from a group of previously published studies that examined how load carriage impacts postural stability and balance. The paper authored by the Mason researchers marked the first time a meta-analysis of the effects of load carriage on center of pressure measurements of postural stability had ever been conducted.

The meta-analysis confirmed what Mason researchers had expected to find—namely, that load carriage affects postural stability. The Mason researchers cited previous studies showing that unbalanced loads require the central nervous system to take corrective actions to maintain postural stability and that this is often the reason that individuals will lean forward or backward in trying to retain their balance. The review of the data showed that load magnitude and load placement are factors that can significantly affect postural sway and stability. Mason researchers determined that “the least impactful form of load carriage seems to be conditions where the load mass is minimized and is dispersed evenly across the trunk in a counterbalanced fashion.”

The authors of the study conclude that with the loss of balance being a common mechanism of injury for individuals who are frequently exposed to load carriage, preventative measures should be taken to lessen the likelihood of injury. Given the strong evidence that load magnitude and load placement influence the effect of load carriage on postural stability, Mason researchers suggested that it would be advisable for individuals to train with load magnitudes and placements resembling what would be encountered in their real-life occupational activities. The authors of the paper also recommended that future research should examine additional factors contributing to differences in individual postural stability responses to load carriage such as changes in muscle activation and prior load carriage experience.

To learn more about how load carriage can impact postural stability, read this article by Joel Martin, associate professor at George Mason University’s School of Kinesiology, and Megan Sax van der Weyden, Kinesiology PhD student. Mason’s Kinesiology program offers degree options that focus on the scientific study of human movement and its application in a variety of occupational, recreational, and clinical settings. Please visit our website for more information.