Horizontal plane pelvic rotation reduces downward COM displacement by advancing which part of the body?

Horizontal plane pelvic rotation reduces downward COM displacement by advancing which part of the body?

• A. The entire swing limb forward
• B. The stance arm
• C. The heel backward
• D. The opposite shoulder backward only

Answer: (A)

Advancing the entire swing limb forward lets the body stay more balanced over the stance leg as you transfer weight. When the pelvis rotates in the horizontal plane and the swing leg moves forward, the mass of the body shifts in the direction of progression, smoothing the center of mass path and reducing how much it has to move up and down. The forward swing of the leg effectively keeps the body from dipping downward as you step, which lowers downward COM displacement. Movement of the stance arm, the heel being pushed backward, or rotating only the opposite shoulder backward doesn’t produce the same effect on the vertical movement of the center of mass during this rotation, so they’re not as effective in reducing downward COM displacement.

Advancing the entire swing limb forward lets the body stay more balanced over the stance leg as you transfer weight. When the pelvis rotates in the horizontal plane and the swing leg moves forward, the mass of the body shifts in the direction of progression, smoothing the center of mass path and reducing how much it has to move up and down. The forward swing of the leg effectively keeps the body from dipping downward as you step, which lowers downward COM displacement.

Movement of the stance arm, the heel being pushed backward, or rotating only the opposite shoulder backward doesn’t produce the same effect on the vertical movement of the center of mass during this rotation, so they’re not as effective in reducing downward COM displacement.