Which combination reduces downward displacement of the center of mass during gait?

Which combination reduces downward displacement of the center of mass during gait?

• A. Frontal plane hip rotation and stance knee flexion
• B. Frontal plane pelvic rotation and stance knee flexion
• C. Hip abduction and knee extension
• D. Horizontal plane pelvic rotation and sagittal plane ankle rotation

Answer: (D)

The amount the center of mass drops during gait is controlled by smooth, coordinated multi-planar movements that damp vertical motion as weight shifts from one leg to the other. Rotating the pelvis in the horizontal (transverse) plane helps keep the trunk oriented with the advancing limb, so the body doesn’t have to drop as much to transfer weight. At the same time, rotating the ankle in the sagittal plane—through controlled dorsiflexion after heel strike and subsequent plantarflexion during push-off—creates an ankle rocker. This mechanism allows the tibia to advance over the foot smoothly, reducing abrupt vertical lowering of the body. Together, these two actions manage how the limb moves in the sagittal and transverse planes to maintain a steadier vertical position of the body, more effectively than strategies focusing primarily on frontal-plane motions or just knee alignment.

The amount the center of mass drops during gait is controlled by smooth, coordinated multi-planar movements that damp vertical motion as weight shifts from one leg to the other. Rotating the pelvis in the horizontal (transverse) plane helps keep the trunk oriented with the advancing limb, so the body doesn’t have to drop as much to transfer weight. At the same time, rotating the ankle in the sagittal plane—through controlled dorsiflexion after heel strike and subsequent plantarflexion during push-off—creates an ankle rocker. This mechanism allows the tibia to advance over the foot smoothly, reducing abrupt vertical lowering of the body.

Together, these two actions manage how the limb moves in the sagittal and transverse planes to maintain a steadier vertical position of the body, more effectively than strategies focusing primarily on frontal-plane motions or just knee alignment.