Reactive Postural Responses to Continuous Yaw Perturbations in Healthy Humans: The Effect of Aging

Abstract

Maintaining balance stability while turning in a quasi-static stance and/or in dynamic motion requires proper recovery mechanisms to manage sudden center-of-mass displacement. Furthermore, falls during turning are among the main concerns of community-dwelling elderly population. This study investigates the effect of aging on reactive postural responses to continuous yaw perturbations on a cohort of 10 young adults (mean age 28 ± 3 years old) and 10 older adults (mean age 61 ± 4 years old). Subjects underwent external continuous yaw perturbations provided by the RotoBit 1D platform. Different conditions of visual feedback (eyes opened and eyes closed) and perturbation intensity, i.e., sinusoidal rotations on the horizontal plane at different frequencies (0.2 Hz and 0.3 Hz), were applied. Kinematics of axial body segments was gathered using three inertial measurement units. In order to measure reactive postural responses, we measured body-absolute and joint absolute rotations, center-of-mass displacement, body sway, and inter-joint coordination. Older adults showed significant reduction in horizontal rotations of body segments and joints, as well as in center-of-mass displacement. Furthermore, older adults manifested a greater variability in reactive postural responses than younger adults. The abnormal reactive postural responses observed in older adults might contribute to the well-known age-related difficulty in dealing with balance control during turning.

Estimation of Human Center of Mass Position through the Inertial Sensors-Based Methods in Postural Tasks: An Accuracy Evaluation

“…In addition, the kinematics parameters commonly used in postural evaluations [ 10 ], such as (a) the range of motion of CoM displacement in the AP (AP Sway) and ML (ML Sway) directions, (b) the total path length in the AP and the ML plane, divided by the task duration (Mean Sway Velocity), and (c) the 95% confidence ellipse area (95% Sway Area) were computed for all methods. For the kinematic parameters, the accuracy of the methods was estimated by considering the following error: where x i is the kinematic parameter obtained with BM or SDI and x OS is the corresponding reference value obtained with OS.…”

“…The assessment of the motion of human Center of Mass (CoM) is of uttermost importance in ergonomics [ 1 , 2 , 3 ], sporting [ 4 , 5 , 6 ], and clinical practice [ 7 , 8 , 9 , 10 ], since it contributes to the quantitative measurements of risky imbalance and postural impairments of humans.…”

Assessing the Effects of Kata and Kumite Techniques on Physical Performance in Elite Karatekas

“…The evaluated point can be assumed as the center of pressure (COP); then, the antero-posterior (AP) and the medio-lateral components (ML) of the COP were computed. Finally, as stability indices we computed parameters that are typical considered in posturographic analysis [40][41][42]. Specifically, the path length (PL), the ellipse area (EA) and the mean frequency (FREQ) were evaluated by following the equations reported in Reference [41].…”

On the OCRA Measurement: Automatic Computation of the Dynamic Technical Action Frequency Factor

“…Linear accelerations and angular velocities were gathered from 17 wearable inertial sensors (MVN Biomech Awinda, Xsens Technologies, The Netherlands) positioned on the following body segments: head, neck, 8th and 10th thoracic vertebra, 3rd and 5th lumbar vertebra, right and left shoulder, right and left arm, right and left forearm, right and left hand, pelvis, right and left thigh, right and left shank, right and left foot, and, right and left forefoot. Inertial sensors were selected among other wearable sensors due to their widespread use in applications for human motion recognition [30][31][32][33][34]. Figure 1 shows the placement of inertial sensor on a worker in an industrial scenario.…”