Muscle Contributions to Balance Control During Amputee and Nonamputee Stair Ascent

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Nicole G. Harper ◽  
Jason M. Wilken ◽  
Richard R. Neptune
Keyword(s):  
Angular Momentum ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Balance Control ◽  
Dynamic Balance ◽  
Frontal Plane ◽  
Rate Of Change ◽  
Prosthetic Devices ◽  
Stair Ascent

Abstract Dynamic balance is controlled by lower-limb muscles and is more difficult to maintain during stair ascent compared to level walking. As a result, individuals with lower-limb amputations often have difficulty ascending stairs and are more susceptible to falls. The purpose of this study was to identify the biomechanical mechanisms used by individuals with and without amputation to control dynamic balance during stair ascent. Three-dimensional muscle-actuated forward dynamics simulations of amputee and nonamputee stair ascent were developed and contributions of individual muscles, the passive prosthesis, and gravity to the time rate of change of angular momentum were determined. The prosthesis replicated the role of nonamputee plantarflexors in the sagittal plane by contributing to forward angular momentum. The prosthesis largely replicated the role of nonamputee plantarflexors in the transverse plane but resulted in a greater change of angular momentum. In the frontal plane, the prosthesis and nonamputee plantarflexors contributed oppositely during the first half of stance while during the second half of stance, the prosthesis contributed to a much smaller extent. This resulted in altered contributions from the intact leg plantarflexors, vastii and hamstrings, and the intact and residual leg hip abductors. Therefore, prosthetic devices with altered contributions to frontal-plane angular momentum could improve balance control during amputee stair ascent and minimize necessary muscle compensations. In addition, targeted training could improve the force production magnitude and timing of muscles that regulate angular momentum to improve balance control.

scholarly journals Using Biofeedback to Reduce Step Length Asymmetry Impairs Dynamic Balance in People Poststroke

2021 ◽  
pp. 154596832110193
Author(s):  
Sungwoo Park ◽  
Chang Liu ◽  
Natalia Sánchez ◽  
Julie K. Tilson ◽  
Sara J. Mulroy ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Sagittal Plane ◽  
Dynamic Balance ◽  
Objective Measure ◽  
Frontal Plane ◽  
Step Length ◽  
Berg Balance Scale ◽  
Whole Body ◽  
Functional Gait ◽  
Full Body

Background People poststroke often walk with a spatiotemporally asymmetric gait, due in part to sensorimotor impairments in the paretic lower extremity. Although reducing asymmetry is a common objective of rehabilitation, the effects of improving symmetry on balance are yet to be determined. Objective We established the concurrent validity of whole-body angular momentum as a measure of balance, and we determined if reducing step length asymmetry would improve balance by decreasing whole-body angular momentum. Methods We performed clinical balance assessments and measured whole-body angular momentum during walking using a full-body marker set in a sample of 36 people with chronic stroke. We then used a biofeedback-based approach to modify step length asymmetry in a subset of 15 of these individuals who had marked asymmetry and we measured the resulting changes in whole-body angular momentum. Results When participants walked without biofeedback, whole-body angular momentum in the sagittal and frontal plane was negatively correlated with scores on the Berg Balance Scale and Functional Gait Assessment supporting the validity of whole-body angular momentum as an objective measure of dynamic balance. We also observed that when participants walked more symmetrically, their whole-body angular momentum in the sagittal plane increased rather than decreased. Conclusions Voluntary reductions of step length asymmetry in people poststroke resulted in reduced measures of dynamic balance. This is consistent with the idea that after stroke, individuals might have an implicit preference not to deviate from their natural asymmetry while walking because it could compromise their balance. Clinical Trials Number: NCT03916562.

scholarly journals Biologically Inspired Design and Development of a Variable Stiffness Powered Ankle-Foot Prosthesis

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Alexander Agboola-Dobson ◽  
Guowu Wei ◽  
Lei Ren
Keyword(s):  
Lower Limb ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Variable Stiffness ◽  
Plane Motion ◽  
Biologically Inspired ◽  
Passive Rotation ◽  
Ground Conditions ◽  
Biologically Inspired Design

Recent advancements in powered lower limb prostheses have appeased several difficulties faced by lower limb amputees by using a series-elastic actuator (SEA) to provide powered sagittal plane flexion. Unfortunately, these devices are currently unable to provide both powered sagittal plane flexion and two degrees of freedom (2-DOF) at the ankle, removing the ankle’s capacity to invert/evert, thus severely limiting terrain adaption capabilities and user comfort. The developed 2-DOF ankle system in this paper allows both powered flexion in the sagittal plane and passive rotation in the frontal plane; an SEA emulates the biomechanics of the gastrocnemius and Achilles tendon for flexion while a novel universal-joint system provides the 2-DOF. Several studies were undertaken to thoroughly characterize the capabilities of the device. Under both level- and sloped-ground conditions, ankle torque and kinematic data were obtained by using force-plates and a motion capture system. The device was found to be fully capable of providing powered sagittal plane motion and torque very close to that of a biological ankle while simultaneously being able to adapt to sloped terrain by undergoing frontal plane motion, thus providing 2-DOF at the ankle. These findings demonstrate that the device presented in this paper poses radical improvements to powered prosthetic ankle-foot device (PAFD) design.

RUNNING PATTERN GENERATION OF HUMANOID BIPED WITH A FIXED POINT AND ITS REALIZATION

2009 ◽  
Vol 06 (04) ◽  
pp. 631-656 ◽  
Author(s):  
BAEK-KYU CHO ◽  
ILL-WOO PARK ◽  
JUN-HO OH
Keyword(s):  
Fixed Point ◽  
Angular Momentum ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Maximum Velocity ◽  
Frontal Plane ◽  
Numerical Approach ◽  
Pattern Generation ◽  
Upper Body ◽  
Running Pattern

This paper discusses the generation of a running pattern for a humanoid biped and verifies the validity of the proposed method of running pattern generation via experiments. Two running patterns are generated independently in the sagittal plane and in the frontal plane and the two patterns are then combined. When a running pattern is created with resolved momentum control in the sagittal plane, the angular momentum of the robot about the Center of Mass (COM) is set to zero, as the angular momentum causes the robot to rotate. However, this also induces unnatural motion of the upper body of the robot. To solve this problem, the biped was set as a virtual under-actuated robot with a free joint at its support ankle, and a fixed point for a virtual under-actuated system was determined. Following this, a periodic running pattern in the sagittal plane was formulated using the fixed point. The fixed point is easily determined in a numerical approach. In this way, a running pattern in the frontal plane was also generated. In an experiment, a humanoid biped known as KHR-2 ran forward using the proposed running pattern generation method. Its maximum velocity was 2.88 km/h.

The Effect of the TayCo External Ankle Brace on Multidirectional Reach Distance, Balance, and Motion in Collegiate Athletes

2020 ◽  
Vol 25 (6) ◽  
pp. 323-327
Author(s):  
Steven J. Smith ◽  
Cameron J. Powden
Keyword(s):  
Range Of Motion ◽  
Sagittal Plane ◽  
Dynamic Balance ◽  
Plantar Flexion ◽  
Collegiate Athletes ◽  
Frontal Plane ◽  
Plane Motion ◽  
Lower Extremity Function ◽  
Physically Active ◽  
Ankle Brace

Ensuring ankle stability while allowing for functional movement is important when returning patients to physical activity and attempting to prevent injury. The purpose of this study was to examine the effectiveness of the TayCo external and a lace-up ankle brace on lower extremity function, dynamic balance, and motion in 18 physically active participants. Significantly greater range of motion was demonstrated for the TayCo brace compared with the lace-up brace for dorsiflexion and plantar flexion, as well as less range of motion for the TayCo brace compared to the lace-up brace for inversion and eversion. The TayCo brace provided restricted frontal plane motion while allowing increased sagittal plane motion without impacting performance measures.

scholarly journals Accelerometer-Based Navigation in Total Knee Arthroplasty for the Management of Extra-Articular Deformity and Retained Femoral Hardware: Analysis of Component Alignment

Joints ◽  
2019 ◽  
Vol 07 (01) ◽  
pp. 001-007 ◽  
Author(s):  
Andrea Cozzi Lepri ◽  
Matteo Innocenti ◽  
Fabrizio Matassi ◽  
Marco Villano ◽  
Roberto Civinini ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Navigation System ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Control Group ◽  
Navigation Systems ◽  
Level Of Evidence ◽  
Total Knee

Abstract Purpose Recent advances in total knee arthroplasty (TKA) include an accelerometer portable system designed to improve component position and alignment. The purpose of this study is to evaluate whether accelerometer navigation system can be a valuable option in complex TKAs for extra-articular deformity of the lower limb or in case of retained femoral hardware. Methods A group of 13 patients underwent TKA with an accelerometer navigation system. Three patients had a tibial extra-articular deformity, six had a femoral extra-articular deformity, and four had an intramedullary nail in the femur. Preoperative and postoperative mechanical axes were measured from full-length lower extremity radiographs to evaluate alignment. The alignment of prosthetic components in the frontal and sagittal planes was determined by postoperative radiographs. Results At 30-days postoperative radiographic check, the hip knee ankle angle was within 2.0° (0 ± 1) of the neutral mechanical axis. The alignment of the tibial component on the frontal plane was 90.0° (range 89–91) and on the sagittal plane 5.0° (range 3–7). The alignment of the femoral component on the frontal plane was 90.0° (range 89–91) and on the sagittal plane 3.0° (range 0–5). Conclusion The alignment of the prosthetic components has been accurate and comparable to other navigation systems in literature without any increase in surgical times. The accelerometer-based navigation system is therefore a useful technique that can be used to optimize TKA alignment in patients with extra-articular deformity or with lower limb hardware, where the intramedullary guides cannot be applied. Level of Evidence This is an observational study without a control group, Level III.

scholarly journals Manual stabilization reveals a transient role for balance control during locomotor adaptation

2019 ◽  
Author(s):  
Sungwoo Park ◽  
James M. Finley
Keyword(s):  
Angular Momentum ◽  
Balance Control ◽  
Dynamic Balance ◽  
Step Length ◽  
Bipedal Walking ◽  
Whole Body ◽  
Arm Swing ◽  
Angular Momenta ◽  
After Effect ◽  
Potential Factor

AbstractA fundamental feature of human locomotor control is the need to adapt our walking pattern in response to changes in the environment. For example, when people walk on a split-belt treadmill which has belts that move at different speeds, they adapt to the asymmetric speed constraints by reducing their spatiotemporal asymmetry. Here, we aim to understand the role of stability as a potential factor driving this adaptation process. We recruited 24 healthy, young adults to adapt to walking on a split-belt treadmill while either holding on to a handrail or walking with free arm swing. We measured whole-body angular momentum and step length asymmetry as measures of dynamic balance and spatiotemporal asymmetry, respectively. To understand how changes in intersegmental coordination influenced measures of dynamic balance, we also measured segmental angular momenta and the coefficient of limb cancellation. When participants were initially exposed to the asymmetry in belt speeds, we observed an increase in whole-body angular momentum that was due to both an increase in the momentum of individual limb segments and a reduction in limb cancellation. Holding on to a handrail reduced the perturbation to asymmetry during the early phase of adaptation and resulted in a smaller after-effect during post-adaptation. In addition, the stabilization provided by holding on to a handrail led to reductions in the coupling between angular momentum and asymmetry. These results suggest that regulation of dynamic balance is most important during the initial, transient phase of adaptation to walking on a split-belt treadmill.Summary StatementRegulation of balance exhibits a transient effect on adaptation to imposed asymmetries during bipedal walking. External stabilization attenuates initial deviations in spatiotemporal asymmetry but has no effect on subsequent adaptation.

Sensitivity of the Toe Height to Multijoint Angular Changes in the Lower Limbs During Unobstructed and Obstructed Gait

2020 ◽  
pp. 1-9
Author(s):  
Chuyi Cui ◽  
Brittney Muir ◽  
Shirley Rietdyk ◽  
Jeffrey Haddad ◽  
Richard van Emmerik ◽  
...  
Keyword(s):  
Young Adults ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Singular Value ◽  
Lower Limbs ◽  
Joint Angles ◽  
Adult Lifespan ◽  
Main Contributor ◽  
Bilateral Lower Limb

Tripping while walking is a main contributor to falls across the adult lifespan. Trip risk is proportional to variability in toe clearance. To determine the sources of this variability, the authors computed for 10 young adults the sensitivity of toe clearance to 10 bilateral lower limb joint angles during unobstructed and obstructed walking when the lead and the trail limb crossed the obstacle. The authors computed a novel measure—singular value of the appropriate Jacobian—as the combined toe clearance sensitivity to 4 groups of angles: all sagittal and all frontal plane angles and all swing and all stance limb angles. Toe clearance was most sensitive to the stance hip ab/adduction for unobstructed gait. For obstructed gait, sensitivity to other joints increased and matched the sensitivity to stance hip ab/adduction. Combined sensitivities revealed critical information that was not evident in the sensitivities to individual angles. The combined sensitivity to stance limb angles was 84% higher than swing limb angles. The combined sensitivity to the sagittal plane angles was lower than the sensitivity to the frontal plane angles during unobstructed gait, and this relation was reversed during obstacle crossing. The results highlight the importance of the stance limb joints and indicate that frontal plane angles should not be ignored.

scholarly journals Effect of Milwaukee brace on static and dynamic balance of female hyperkyphotic adolescents

2012 ◽  
Vol 37 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Arezoo Eshraghi ◽  
Nader Maroufi ◽  
Mohammad Ali Sanjari ◽  
Hassan Saeedi ◽  
Mohammad Reza Keyhani ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Center Of Pressure ◽  
Balance Control ◽  
Dynamic Balance ◽  
Normal Subjects ◽  
Balance Performance ◽  
Functional Reach ◽  
Significant Difference ◽  
The Right ◽  
Milwaukee Brace

Background: Biomechanical factors, such as spinal deformities can result in balance control disorders. Objectives: The purpose of this study was to examine the effect of bracing on static and dynamic balance control of hyperkyphotic female adolescents. Study Design: Clinical trial. Methods: A force platform was employed to record center of pressure (COP) parameters. Ten adolescents undergoing Milwaukee brace for hyperkyphosis and 14 normal subjects participated in the study. The COP data were collected with and without brace immediately on first day and after 120 days of continuous brace wear. Results: No significant difference was found in dynamic and static balance tests with and without brace on the first day ( P > 0.05). After 120 days, the values of COP displacement in functional reach to the right and left for the hyperkyphotic adolescents when performing without brace enhanced significantly compared to the first day. The forward reach distance was not significantly different between the normal and hyperkyphotic subjects ( P = 0.361); however, hyperkyphotic participants had significantly smaller reach distance in the functional reach to the right (21.88 vs. 25.56cm) and left (17.04 vs. 21.25cm). Conclusion: It might be concluded that bracing had a possible effect on improvement of dynamic balance performance, because the subjects could reach the target in dynamic reach tests with higher displacement in sagittal plane without losing their balance control. Clinical relevance Little is known about the biomechanical aspects of brace wear in individuals with hyperkyphosis. This study investigated balance differences between the healthy and hyperkyphotic individuals, and outcomes of Milwaukee brace wear. It might provide some new insight into the conservative treatment of hyperkyphosis for clinicians and researchers.

Changes in the dynamic balance level of winter sports players, candidates for ZSMS Zakopane in the years 2007-2016

2019 ◽  
Vol 29 (88) ◽  
pp. 28-40
Author(s):  
Dariusz Tchórzewski ◽  
Janusz Brudecki ◽  
Janusz Jaworski ◽  
Przemysław Bujas
Keyword(s):  
High School ◽  
High School Students ◽  
Junior High ◽  
Sagittal Plane ◽  
Dynamic Balance ◽  
Frontal Plane ◽  
Difficulty Level ◽  
School Students ◽  
Winter Sports ◽  
Motor Fitness

Research aim. The objective of the work is to determine the changes in the level of ability to maintain balance in dynamic conditions among winter sports players, candidates for junior-high and high school of the Zakopane Sports Championship Team (ZSMS) over the last decade. The following research questions were formulated: 1. Have there been significant changes in the level of dynamic balance of winter sports candidates at ZSMS Zakopane in the last ten years? 2. Did any changes have a similar range in the subjects in both analysed tilt directions (anterior-posterior and lateral)? 3. Did the differences in the level of dynamic balance between 13- and 16-year-old candidates maintain at a similar level during the examined period? Materials and methods. The study included a 133 group of boys, junior-high candidates (age 13.32 ± 0.77) and a 198 group of high school students (age 16.02 ± 0.48). To determine the level of balance on an unstable surface, the Libra balance platform of the Italian company EasyTech was used. A sine wave with an amplitude of 5° and a frequency of 10 cycles/min were used as the path pattern. The balance curvature r=40 cm and the sixth difficulty level (deviation from the reference line by 5° in each direction) were applied. The following results were used for the analysis: stability index (SI), total area (TA) and index of balance precision (IBP). The tests were carried out separately for the frontal and sagittal planes. Before the measurements were taken, the basic somatic features of the subjects were measured. The diversity of the results of individual stability parameters was verified via the Kruskal-Wallis and the Mann-Whitney U tests. Results. Over the decade, in both 13- and 16-year-olds, significant improvement in the value of all tested parameters of stability in the frontal plane was noted. Among junior-high school students, these equalled: SI=40.5%; TA=30.0%; IBP=52.5%, whereas for high-school students, the values totalled: SI=32.1%; TA=23.6%; IBP=49.4%. However, the occurrence of such positive changes in the sagittal plane has not been confirmed. Similarly, 13-year-olds improved their results in the following range: SI=22.9%; TA=18.2%; IBP=33.5%, while for 16-year-olds, these were: SI=11.6%; TA=9.9%; IBP=16.8%. There was a gradual disappearance of differences in the level of balance between the junior- and high-school ZSMS candidates. Conclusions. Analysis of changes in the level of dynamic balance of winter sports players over the decade indicates that this ability has not yielded to trends characterising the nationwide population in the field of motor fitness. The presented results indicate either constant improvement in the stability of the subjects (frontal plane) or maintaining it at a good, stable level (sagittal plane). This is an optimistic conclusion, because many authors believe that the results obtained on balance platforms not only characterise the level of postural stability of subjects, but also that the speed of adaptation to the conditions of the unstable ground is a determinant of the level of coordination abilities of a subject.

Standardizing Methodology for Research with Uneven Terrains Focused on Dynamic Balance During Gait

2016 ◽  
Vol 32 (6) ◽  
pp. 599-602
Author(s):  
Timothy D. Coleman ◽  
Haley J. Lawrence ◽  
W. Lee Childers
Keyword(s):  
Angular Momentum ◽  
Sagittal Plane ◽  
Dynamic Balance ◽  
Human Gait ◽  
Camera Motion ◽  
Step Width ◽  
Arm Swing ◽  
Margin Of Stability ◽  
Significant Difference ◽  
Trunk Sway

This research tested a reproducible uneven walkway designed to destabilize human gait. Ten participants walked 30 times over even and uneven (7.3 × .08 m, sequentially-placed wooden blocks in a rotating pattern, 1-cm thick rubber mat) walkways. A full-body marker set and 8-camera motion capture system recorded limb kinematics. MatLab 2013b was used to calculate measures of gait stability: angular momentum, margin of stability, step width variability, CoM height, toe clearance, lateral arm swing. The minimum number of strides necessary to minimize intraparticipant variability was calculated via the interquartile range/median ratio (IMR) at 25% and 10% thresholds for each measure. A paired t test tested for significance between terrains (P < .05). The uneven walkway significantly destabilized gait as seen by increases in: coronal and sagittal plane angular momentum, step width variability, and toe clearance. We found no significant difference with the margin of stability between the 2 terrains possibly due to compensatory strategies (eg, lateral arm swing, trunk sway, step width). Recording a minimum of 10 strides per subject will keep each variable between the 25% and 10% IMR thresholds. In conclusion, the uneven walkway design significantly destabilizes human gait and at least 10 strides should be collected per subject.

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