A refined view of the determinants of gait.

We evaluated the effect of reducing the vertical displacement of the centre of mass (COM) on the six determinants of gait proposed by Saunders, Inman and Eberhart in 30 healthy adults. We compared the estimated reduction in COM vertical displacement due to the determinants in their compass model with the actual reduction of vertical displacement. The maximum height of the COM for the compass gait model occurred earlier than the actual COM maximum height. Different gait functions were determinant in reducing COM vertical displacement. In both cases heel rise was the main determinant (up to 2/3 of total reduction). Pelvic obliquity and single stance knee flexion contributions were more important when compass gait COM maximum was used while they were barely detectable at the actual COM maximum. Ipsi- and contra-lateral knee flexion were detrimental to the reduction of COM vertical displacements, while pelvic rotation contribution was beneficial and accounted for up to 10% of the overall COM vertical displacement reduction. Although a reduction of COM vertical displacement may have important energy implications, determining the specific gait parameters associated with this function is fundamental in understanding gait disability.

Women's shoes and knee osteoarthritis.

We assessed whether wearing wide-heeled shoes has a similar effect on knee torque to narrow-heeled shoes by measuring the joint torques of 20 healthy women during walking. Wearing wide-heeled shoes had a 30% greater effect on peak external knee flexor torque than walking barefoot. Walking with wide-heeled and narrow-heeled shoes increased peak knee varus torque by 26% and 22%, respectively. Our findings imply that wide-heeled shoes cause abnormal forces across the patellofemoral and medial compartments of the knee, which are the typical anatomical sites for degenerative joint changes.

Quantification of pelvic rotation as a determinant of gait.

OBJECTIVE: To evaluate the effect of pelvic rotation, originally described as the first determinant of gait, on reducing the vertical displacement of the center of mass (COM) during comfortable speed walking. DESIGN: Pelvic and lower extremity kinematic data during walking were collected. A modified compass gait model incorporating measured inputs was used to estimate the effect of pelvic rotation on reducing the vertical displacement of the COM. The actual reduction in vertical displacement was also calculated. SETTING: A gait laboratory. PARTICIPANTS: Thirty able-bodied subjects. MAIN OUTCOME MEASURE: The estimated reduction in COM vertical displacement caused by pelvic rotation was compared with the actual reduction in COM displacement. RESULTS: The estimated effect of pelvic rotation in reducing COM displacement was 2.5 +/- 1.1mm, accounting for only 12% of the actual reduction. CONCLUSION: During normal comfortable speed walking by able-bodied subjects, pelvic rotation contributes only a small portion of the actual reduction in the vertical displacement of the COM compared with a compass gait model. Other primary gait factors or determinants are needed to explain the actual reduction in vertical displacement of the COM.