scholarly journals Mechanical Effects of Canes on Postural Control: Beyond Perceptual Information

2021 ◽  
Author(s):  
Marta Russo ◽  
Jongwoo Lee ◽  
Neville Hogan ◽  
Dagmar Sternad
Keyword(s):  
Irrelevant Dimension ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Frontal Plane ◽  
Perceptual Information ◽  
Support Needs ◽  
Haptic Information ◽  
Shoulder Stiffness ◽  
Mechanical Effects ◽  
Task Irrelevant

Abstract BackgroundNumerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. MethodsSixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. ResultsResults showed that canes significantly reduced the variability of the center of pressure and center of mass to the same level as when standing on the ground. In the preferred condition, participants exploited the altered mechanics by resting their arms on the canes and, in the tripod configuration, allowing for larger CoP motions in the task-irrelevant dimension. Increasing the exerted force beyond the preferred level yielded no further benefits, in fact had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. ConclusionsDespite the challenge of a statically unstable system, these results show that, in addition to augmenting perceptual information, using canes can provide mechanical benefits and challenges. First, the controller minimizes effort channeling noise in the task-irrelevant dimensions and, second, resting the arms on the canes but avoiding large forces that would have destabilizing effects. However, if maximal force is applied to the canes, the instability of the support needs to be counteracted, possibly by arm and shoulder stiffness.

Strategies for maintaining dynamic balance in persons with neurological disorders during overground walking

2021 ◽  
pp. 095441192110236
Author(s):  
Tiziana Lencioni ◽  
Denise Anastasi ◽  
Ilaria Carpinella ◽  
Anna Castagna ◽  
Alessandro Crippa ◽  
...  
Keyword(s):  
Neurological Disorder ◽  
Center Of Pressure ◽  
Balance Control ◽  
Dynamic Balance ◽  
Objective Assessment ◽  
Center Of Mass ◽  
Frontal Plane ◽  
Rehabilitation Program ◽  
Lower Limbs ◽  
Lateral Direction

Maintaining a stable gait requires a dynamic balance control, that can be altered in persons with Multiple Sclerosis (MS), Stroke (ST), and Parkinson’s disease (PD). The understanding of the strategy for Center of Mass (CoM) positioning adopted by patients during walking is important to be able to program treatments aimed at improving gait control and preventing falls. Forty-four persons with a mild-to-moderate neurological disorder (20 with MS, 14 with ST, 10 with PD) underwent clinical examination and gait analysis. Ten Healthy Subjects (HS) walking at matched speed provided the normative data. Dynamic balance was assessed using the margin of stability (MoS). It was calculated as the distance between the extrapolated Center of Pressure and the extrapolated CoM at mid-stance. The MoS values for lower limbs were calculated in patients and compared with speed-matched values of HS. Persons with neurological disorder showed increased MoS in the medio-lateral direction with respect to HS. Within-group comparison analysis showed a symmetry between lower limbs in HS (Mean (95%CI) [mm], dominant vs non-dominant limb, 43.3 (31.9–54.6) vs 42.9 (28.8–56.9)) and PD (less affected vs more affected limb, 71.1 (59.8–82.5) vs 72.5 (58.5–86.6)), while a significant asymmetry was found in MS (54.4 (46.4–62.4) vs 81.1 (71.2–91.1)) and ST (52.1 (42.6–61.7) vs 74.7 (62.8–86.6)) participants. The history of falls was comparable among PD, MS, and ST groups, and the MoS in the frontal plane showed a strong correlation with these records. Objective assessment of MoS revealed pathology-specific strategies showing different impacts in MS, ST, and PD on the ability to control CoM information to manage the balance between limbs during gait. MoS evaluation will provide useful information to address a tailored rehabilitation program and to monitor disease progression.

EFFECTS OF KNEE OSTEOARTHRITIS ON BODY'S CENTER OF MASS MOTION IN OLDER ADULTS DURING LEVEL WALKING

2010 ◽  
Vol 22 (03) ◽  
pp. 205-212 ◽  
Author(s):  
Ting-Ming Wang ◽  
Wei-Chun Hsu ◽  
Chu-Fen Chang ◽  
Chih-Chung Hu ◽  
Tung-Wu Lu
Keyword(s):  
Knee Osteoarthritis ◽  
Dynamic Stability ◽  
Sagittal Plane ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Frontal Plane ◽  
Mass Motion ◽  
Knee Oa ◽  
Level Walking ◽  
Normal Controls

Knowledge of the control of the body's dynamic stability in patients with knee osteoarthritis (OA) is helpful for the management of these patients and for the evaluation of treatment outcomes. The purpose of the current study was to investigate the dynamic stability of patients with knee OA during level walking using variables describing the motion of the body's center of mass (COM) and its relationship to the center of pressure (COP). Kinematic and kinetic data during level walking were obtained from 10 patients with bilateral knee OA and 10 normal controls using a motion analysis system and two forceplates. Compared to the normal controls, patients with knee OA exhibited normal COM positions and velocities at key instances of gait but with significant changes in COM accelerations. In the sagittal plane, adjustments to the anterioposterior acceleration of the COM throughout the complete gait cycle were needed for better control of the COM during the more challenging latter half of single leg stance. Diminished A/P COM–COP separation was also used to maintain body stability with reduced joint loadings. In the frontal plane, this was achieved by increasing the acceleration of the body's COM towards the stance leg. The more jerky motion of the body's COM observed may be a result of reduced ability associated with knee OA in the control of the motion of the COM. Strengthening of the muscles of the lower extremities, as well as training of the control of the COM through a dynamic balance training program, are equally important for the dynamic stability of patients with knee OA.

scholarly journals Transfer and generalization of learned manipulation between unimanual and bimanual tasks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Trevor Lee-Miller ◽  
Marco Santello ◽  
Andrew M. Gordon
Keyword(s):  
Learning Transfer ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Pressure Point ◽  
Torque Generation ◽  
Before And After ◽  
Object Center ◽  
High Level ◽  
Bimanual Grasping ◽  
Partial Learning

AbstractSuccessful object manipulation, such as preventing object roll, relies on the modulation of forces and centers of pressure (point of application of digits on each grasp surface) prior to lift onset to generate a compensatory torque. Whether or not generalization of learned manipulation can occur after adding or removing effectors is not known. We examined this by recruiting participants to perform lifts in unimanual and bimanual grasps and analyzed results before and after transfer. Our results show partial generalization of learned manipulation occurred when switching from a (1) unimanual to bimanual grasp regardless of object center of mass, and (2) bimanual to unimanual grasp when the center of mass was on the thumb side. Partial generalization was driven by the modulation of effectors’ center of pressure, in the appropriate direction but of insufficient magnitude, while load forces did not contribute to torque generation after transfer. In addition, we show that the combination of effector forces and centers of pressure in the generation of compensatory torque differ between unimanual and bimanual grasping. These findings highlight that (1) high-level representations of learned manipulation enable only partial learning transfer when adding or removing effectors, and (2) such partial generalization is mainly driven by modulation of effectors’ center of pressure.

Letter to the editor regarding “The assessment of center of mass and center of pressure during quiet stance: Current applications and future directions”

2021 ◽  
Vol 128 ◽  
pp. 110729
Author(s):  
Peter Federolf ◽  
Rosa M Angulo-Barroso ◽  
Albert Busquets ◽  
Blai Ferrer-Uris ◽  
Øyvind Gløersen ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Center Of Mass ◽  
Quiet Stance ◽  
Future Directions ◽  
Letter To The Editor

scholarly journals Habitual Physical Activity as a Determinant of the Effect of Moderate Physical Exercise on Postural Control in Older Men

2012 ◽  
Vol 7 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Rafał Stemplewski ◽  
Janusz Maciaszek ◽  
Maciej Tomczak ◽  
Robert Szeklicki ◽  
Dorota Sadowska ◽  
...  
Keyword(s):  
Physical Activity ◽  
Postural Control ◽  
Sagittal Plane ◽  
Center Of Pressure ◽  
Force Plate ◽  
Frontal Plane ◽  
Habitual Physical Activity ◽  
Similar Reaction ◽  
Mean Velocity ◽  
Ergometer Exercise

The aim of the study was to compare the effect of exercise on postural control (PC) among the elderly with lower or higher level of habitual physical activity (HPA). The study involved 17 elderly men (mean age 72.9 ± 4.79 years). Mean velocity of the center of pressure (COP) displacements was measured using a force plate both before and after cycle ergometer exercise. A significantly higher increase in mean velocity of COP displacements and its component in the sagittal plane were observed in the group with lower level of HPA in comparison with the group with higher HPA level. Simultaneously, a relatively similar reaction to the exercise in the frontal plane was observed in both groups, possibly connected to the specific type of used exercise, which mainly activated the sagittal muscles.

scholarly journals Can Muscle Stiffness Alone Stabilize Upright Standing?

1999 ◽  
Vol 82 (3) ◽  
pp. 1622-1626 ◽  
Author(s):  
Pietro G. Morasso ◽  
Marco Schieppati
Keyword(s):  
Center Of Pressure ◽  
Center Of Mass ◽  
Muscle Stiffness ◽  
The Body ◽  
Ankle Muscles ◽  
Upright Standing ◽  
Stiffness Control ◽  
Control Patterns ◽  
Physiological Values

A stiffness control model for the stabilization of sway has been proposed recently. This paper discusses two inadequacies of the model: modeling and empiric consistency. First, we show that the in-phase relation between the trajectories of the center of pressure and the center of mass is determined by physics, not by control patterns. Second, we show that physiological values of stiffness of the ankle muscles are insufficient to stabilize the body “inverted pendulum.” The evidence of active mechanisms of sway stabilization is reviewed, pointing out the potentially crucial role of foot skin and muscle receptors.

scholarly journals Active foot placement control ensures stable gait: Effect of constraints on foot placement and ankle moments

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242215
Author(s):  
A. M. van Leeuwen ◽  
J. H. van Dieën ◽  
A. Daffertshofer ◽  
S. M. Bruijn
Keyword(s):  
Steady State ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Reaction Force ◽  
Stride Frequency ◽  
Tight Control ◽  
Foot Placement ◽  
Ankle Moment ◽  
Reaction Forces ◽  
Moment Control

Step-by-step foot placement control, relative to the center of mass (CoM) kinematic state, is generally considered a dominant mechanism for maintenance of gait stability. By adequate (mediolateral) positioning of the center of pressure with respect to the CoM, the ground reaction force generates a moment that prevents falling. In healthy individuals, foot placement is complemented mainly by ankle moment control ensuring stability. To evaluate possible compensatory relationships between step-by-step foot placement and complementary ankle moments, we investigated the degree of (active) foot placement control during steady-state walking, and under either foot placement-, or ankle moment constraints. Thirty healthy participants walked on a treadmill, while full-body kinematics, ground reaction forces and EMG activities were recorded. As a replication of earlier findings, we first showed step-by-step foot placement is associated with preceding CoM state and hip ab-/adductor activity during steady-state walking. Tight control of foot placement appears to be important at normal walking speed because there was a limited change in the degree of foot placement control despite the presence of a foot placement constraint. At slow speed, the degree of foot placement control decreased substantially, suggesting that tight control of foot placement is less essential when walking slowly. Step-by-step foot placement control was not tightened to compensate for constrained ankle moments. Instead compensation was achieved through increases in step width and stride frequency.

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