Approximately how many centimeters is side-to-side COM displacement during normal gait?

Approximately how many centimeters is side-to-side COM displacement during normal gait?

• A. 4 cm
• B. 10 cm
• C. 1 cm
• D. 15 cm

Answer: (A)

When we walk, the body shifts its weight from one leg to the other, so the center of mass moves side to side. In healthy adults, this lateral movement is modest, only a few centimeters, so the COM stays safely over the stance foot during each step. The typical peak side-to-side displacement is about 4 cm. This amount of sway allows balance and forward progress without wasting energy or losing stability. If the shift were as small as 1 cm, the body wouldn’t adjust enough to maintain stability through the step; if it were much larger—around 10 cm or 15 cm—the balance would be harder to control and gait would appear unstable. So, approximately 4 cm best matches normal gait.

When we walk, the body shifts its weight from one leg to the other, so the center of mass moves side to side. In healthy adults, this lateral movement is modest, only a few centimeters, so the COM stays safely over the stance foot during each step. The typical peak side-to-side displacement is about 4 cm. This amount of sway allows balance and forward progress without wasting energy or losing stability. If the shift were as small as 1 cm, the body wouldn’t adjust enough to maintain stability through the step; if it were much larger—around 10 cm or 15 cm—the balance would be harder to control and gait would appear unstable. So, approximately 4 cm best matches normal gait.