Restriction of pelvic lateral and rotational motions alters lower limb kinematics and muscle activation pattern during over-ground walking.

Restriction of pelvic lateral and rotational motions caused by robotic gait assistive devices can hinder satisfactory functional outcomes as it alters normal gait patterns. However, the effect of pelvic motion restriction caused by assistive devices on human locomotion is still unclear; thus, we empirically evaluated the influences of pelvic lateral and rotational motions on gait during over-ground walking by inhibiting the respective pelvic motions. The pelvic motions were restricted through a newly developed over-ground walking device. Variations in gait descriptive parameters as well as joint kinematics and muscle activation patterns were measured to indicate gait difference caused by pelvic restrictions. The results showed that pelvic lateral and rotational restriction significantly reduced the stride and step length as well as gait velocity and increased ratio of stance phase. It was also observed that the restriction caused a significant reduction in the range of motion of the ankle, knee, and hip joints. In addition, significantly higher muscle activations and prolonged patterns were observed in the tibialis anterior, gastrocnemius, and biceps femoris muscles, as compared to the normal patterns when the pelvis was restricted. We concluded that the pelvic restriction significantly altered normal gait dynamics, thus inhibiting the efficacy of gait rehabilitation.