The effect of walking speed on center of mass displacement

Abstract

The movement of the center of mass (COM) during human walking has been hypothesized to follow a sinusoidal pattern in the vertical and mediolateral directions. The vertical COM displacement has been shown to increase with velocity, but little is known about the mediolateral movement of the COM. In our evaluation of the mediolateral COM displacement at several walking speeds, 10 normal subjects walked at their self-selected speed and then at 0.7, 1.0, 1.2, and 1.6 m/s in random order. We calculated COM location from a 15segment, full-body kinematic model using segmental analysis. Mediolateral COM displacement was 6.99 +/-1.34 cm at the slowest walking speed and decreased to 3.85 +/-1.41 cm at the fastest speed (p < 0.05). Vertical COM excursion increased from 2.74 +/-0.52 at the slowest speed to 4.83 +/-0.92 at the fastest speed (p < 0.05). The data suggest that the relationship between the vertical and mediolateral COM excursions changes substantially with walking speed. Clinicians who use observational gait analysis to assess walking problems should be aware that even normal individuals show significant mediolateral COM displacement at slow speeds. Excessive vertical COM displacement that is obvious at moderate walking speeds may be masked at slow walking speeds.Abbreviations: ANOVA = analysis of variance, COM = center of mass, fps = frames per second, SS = self-selected.

ZeroG: Overground gait and balance training system

“…That is, gait speeds typical of patients using ZeroG will be under those of community ambulators or 0.7 m/s [19]. For walking speeds <0.7 m/s, COM movement in the Z-direction is typically <3 cm [20] with frequencies between 0.5 and 1.0 Hz. In our Table 3 for performance results of large excursion movements.…”

“…We programmed the linear slide to move through three piecewise linear-velocity profiles (20,40, and 60 in./s, or 0.5, 1.0, and 1.5 m/s), repeated 10 times, while BWS was set to 50 lb. These tests allowed us to evaluate the system's performance under controlled movements at various speeds.…”

Center of mass motion and the effects of ankle bracing on metabolic cost during submaximal walking trials

“…This is consistent with the finding that excessive CoMz that is obvious at moderate and fast walking speeds may be masked at slow walking speeds. 10 Also, not much variation occurred in net O 2 cost at slower velocities, indicating that this condition may not have stressed the healthy subjects enough. At faster velocities and in equinus, variation is seen and thus, strong correlations were observed.…”

“…8 Researchers agree that walking in normal subjects is highly efficient because the CoMz is minimized. 10 In addition, equinus gait, also called toe walking, is commonly seen in children with CP and other conditions, and is felt to be an metabolic costly gait pattern. 6,[11][12][13][14] However, information on how much of this cost is due to the equinus foot contact with the floor relative to spasticity and other factors (i.e., reduced strength) has not been studied systematically.…”

Heads Up and Camera Down: A Vision-Based Tracking Modality for Mobile Mixed Reality

“…Vertical motion that occurs as a natural part of the user's walking gait will also introduce error to the motion estimate, as it introduces an offset to the measured height of the camera from the ground. During an average walking motion, the camera will undergo a vertical displacement of approximately 4.5 cm [35], [36]. From (1), we can see that for actual camera motion T , with the camera's height measured as H with vertical displacement d, the measured camera motion T 0 will be…”