Balance-corrective responses to unexpected perturbations at the arms during treadmill walking

2014 ◽  
Vol 112 (7) ◽  
pp. 1790-1800 ◽  
Author(s):  
Juan Forero ◽  
John E. Misiaszek
Keyword(s):  
Arm Movements ◽  
Treadmill Walking ◽  
Heel Strike ◽  
Postural Adjustments ◽  
Balance Task ◽  
Base Of Support ◽  
Walking Aid

The arms have been shown to be involved in the regulation of balance during walking. The use of a walking aid enhances balance by increasing the base of support and reducing the load on the legs by partly transferring it to the arms. However, when actively engaged during a balance task, perturbations to the arms can destabilize balance. Previous studies have investigated postural adjustments associated with focal arm movements during standing and walking. However, balance-corrective reactions to unexpected perturbations to the arms during walking have not been well studied. In the present study, subjects walked on a treadmill while grasping a pair of handles when sudden perturbations were delivered by displacing the handles in the forward or backward direction. Instructing subjects to oppose the displacement of the handles resulted in strong responses in the arms that were accompanied by activation of muscles in the legs, comparable to those observed in other balance disturbance studies. Conversely, when subjects were instructed to allow the handles to move when displaced, no responses were observed in the arms. However, similar responses were observed in the legs whether subjects opposed the displacement of the handles or not when perturbations were applied at heel strike. The results from this study show that balance reactions can be elicited in the legs in response to perturbations applied at the arms, and that the expression of these responses is affected by the task engaged in by the arms.

Postural adjustments for online corrections of arm movements in standing humans

2011 ◽  
Vol 105 (5) ◽  
pp. 2375-2388 ◽  
Author(s):  
Julia A. Leonard ◽  
Valeriya Gritsenko ◽  
Ryan Ouckama ◽  
Paul J. Stapley
Keyword(s):  
Muscle Activity ◽  
Arm Movements ◽  
Task Demands ◽  
Target Displacement ◽  
Postural Adjustments ◽  
Central Target ◽  
Postural Muscle ◽  
Online Corrections ◽  
Standing Humans ◽  
The Right

The aim of this study was to investigate how humans correct ongoing arm movements while standing. Specifically, we sought to understand whether the postural adjustments in the legs required for online corrections of arm movements are predictive or rely on feedback from the moving limb. To answer this question we measured online corrections in arm and leg muscles during pointing movements while standing. Nine healthy right-handed subjects reached with their dominant arm to a visual target in front of them and aligned with their midline. In some trials, the position of the target would switch from the central target to one of the other targets located 15°, 30°, or 45° to the right of the central (midline) target. For each target correction, we measured the time at which arm kinematics, ground reaction forces, and arm and leg muscle electromyogram significantly changed in response to the target displacement. Results show that postural adjustments in the left leg preceded kinematic corrections in the limb. The corrective postural muscle activity in the left leg consistently preceded the corrective reaching muscle activity in the right arm. Our results demonstrate that corrections of arm movements in response to target displacement during stance are preceded by postural adjustments in the leg contralateral to the direction of target shift. Furthermore, postural adjustments preceded both the hand trajectory correction and the arm-muscle activity responsible for it, which suggests that the central nervous system does not depend on feedback from the moving arm to modify body posture during voluntary movement. Instead, postural adjustments lead the online correction in the arm the same way they lead the initiation of voluntary arm movements. This suggests that forward models for voluntary movements executed during stance incorporate commands for posture that are produced on the basis of the required task demands.

Development of anticipatory postural adjustments during locomotion in children

1992 ◽  
Vol 68 (2) ◽  
pp. 542-550 ◽  
Author(s):  
H. Hirschfeld ◽  
H. Forssberg
Keyword(s):  
Muscle Activity ◽  
Swing Phase ◽  
Anticipatory Postural Adjustments ◽  
Heel Strike ◽  
Dependent Manner ◽  
Postural Adjustments ◽  
Postural Activity ◽  
Postural Responses ◽  
Postural Muscle ◽  
Support Phase

1. Anticipatory postural adjustments were studied in children (6-14 yr of age) walking on a treadmill while pulling a handle. Electromyographs (EMGs) and movements were recorded from the left arm and leg. 2. Postural activity in the leg muscles preceded voluntary arm muscle activity in all age groups, including the youngest children (6 yr of age). The latency to both leg and arm muscle activity, from a triggering audio signal, decreased with age. 3. In older children the latency to both voluntary and postural activity was influenced by the phase of the step cycle. The shortest latency to the first activated postural muscle occurred during single support phase in combination with a long latency to arm muscle activity. 4. In the youngest children, there was no phase-dependent modulation of the latency to the activation of the postural muscles. The voluntary activity was delayed during the beginning of the support phase resulting in a long delay between leg and arm muscle activity. 5. The postural muscle activation pattern was modified in a phase-dependent manner in all children. Lateral gastrocnemius (LG) and hamstring muscles (HAM) were activated during the early support phase, whereas tibialis anterior (TA) and quadriceps (Q) muscles were activated during the late support phase and during the swing phase. However, in the 6-yr-old children, LG was also activated in the swing phase. LG was activated before the HAM activity in the youngest children but after HAM in 14-yr-old children and adults. 6. The occurrence of LG activity in postural responses before heel strike suggests an immature (nonplantigrade) gating of postural activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamic Leap and Balance Test: Ability to Discriminate Balance Deficits in Individuals With Chronic Ankle Instability

2020 ◽  
Vol 29 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Abbis H. Jaffri ◽  
Thomas M. Newman ◽  
Brent I. Smith ◽  
Giampietro L. Vairo ◽  
Craig R. Denegar ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Healthy Subjects ◽  
Ankle Instability ◽  
Dynamic Balance ◽  
Chronic Ankle Instability ◽  
Assessment Tools ◽  
Balance Test ◽  
Balance Task ◽  
History Of ◽  
Base Of Support

Context: The Dynamic Leap Balance Test (DLBT) is a new dynamic balance task that requires serial changes in base of support with alternating limb support and recovery of dynamic stability, as compared with the Y modification of the Star Excursion Balance Test (Y-SEBT), which assesses dynamic stability over an unchanging base of support. Objectives: To assess the dynamic balance performance in 2 different types of dynamic balance tasks, the DLBT and the SEBT, in subjects with unilateral chronic ankle instability (CAI) when compared with matched controls. The authors hypothesized that the DLBT score would significantly differ between the CAI involved and uninvolved limbs (contralateral and healthy matched) and demonstrate a modest (r = .50) association with the SEBT scores. Design: Case-control. Setting: Controlled laboratory. Participants: A total of 36 physically active adults, 18 with history of unilateral CAI and 18 without history of ankle injury, were enrolled in the study. CAI subjects were identified using the Identification of Functional Ankle Instability questionnaire. Interventions: The DLBT and the SEBT were performed in a randomized order on a randomly selected limb in CAI and healthy subjects. Main Outcome Measures: Time taken to complete the DLBT and the reach distances performed on the SEBT were compared between the CAI and the healthy subjects. Results: There were no statistically significant differences (P < .05) in SEBT reach distances between groups. The DLBT time was greater (P < .01) for unstable ankles compared with the stable ankle. The authors found no correlation (P > .05) between DLBT time and any of the SEBT reach distances suggesting that the DLBT provides unique information in the assessment of patients with CAI. Conclusion: The DLBT challenges the ability to maintain postural control in CAI subjects differently than the SEBT. There is a need of more dynamic balance assessment tools that are functional and clinically relevant.

Navicula Drop Test Ad Modum Brody

2012 ◽  
Vol 102 (1) ◽  
pp. 34-38 ◽  
Author(s):  
Michael Skovdal Rathleff ◽  
Rasmus Gottschalk Nielsen ◽  
Uwe G. Kersting
Keyword(s):  
Treadmill Walking ◽  
Heel Strike ◽  
Clinical Test ◽  
Start Position ◽  
Foot Motion ◽  
Foot Pronation ◽  
Analysis System ◽  
Asymptomatic Individuals ◽  
Dynamic Measures ◽  
And Function

Background: Understanding foot motion and function during activity is essential for clinicians because different foot types may require different treatment or rehabilitation strategies. Brody introduced the static navicular drop (ND) test, which was meant as a quick clinical test to estimate foot pronation during dynamic conditions. However, how well static ND predicts dynamic ND during walking has never been investigated. The purpose of this study was to investigate how well static ND corresponds to dynamic measures of ND during treadmill walking. Methods: A custom video analysis system was used to assess dynamic ND during treadmill walking. The ND test ad modum Brody was used to evaluate static ND. Results: Static ND showed a significant correlation with dynamic ND (r = 0.357, r2 = 0.127, P &lt; .001). Navicular height at heel strike demonstrated a significant correlation with navicular height at the start position of static ND (r = 0.756, r2 = 0.571 P &lt; .001). Minimal navicular height during walking was significantly correlated with the end position of static ND (r = 0.951, r2 = 0.904, P &lt; .001). Conclusions: This study of asymptomatic individuals did not confirm that static ND can be used to individually predict dynamic ND during treadmill walking. It was demonstrated that the start position of Brody’s test is not well correlated with navicular height at heel strike, with this being the main reason for the weak relationship between static and dynamic ND measures. (J Am Podiatr Med Assoc 102(1): 34–38, 2012)

scholarly journals Characterization of Anticipatory Postural Adjustments in Lateral Stepping: Impact of Footwear and Lower Limb Preference

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8244
Author(s):  
Yuri Russo ◽  
Dragan Marinkovic ◽  
Borislav Obradovic ◽  
Giuseppe Vannozzi
Keyword(s):  
Everyday Life ◽  
Lower Limb ◽  
Force Plate ◽  
Motor Task ◽  
Anticipatory Postural Adjustments ◽  
Postural Adjustments ◽  
Spatiotemporal Parameters ◽  
Base Of Support ◽  
Force Plate Data

Lateral stepping is a motor task that is widely used in everyday life to modify the base of support, change direction, and avoid obstacles. Anticipatory Postural Adjustments (APAs) are often analyzed to describe postural preparation prior to forward stepping, however, little is known about lateral stepping. The aim of the study is to characterize APAs preceding lateral steps and to investigate how these are affected by footwear and lower limb preference. Twenty-two healthy young participants performed a lateral step using both their preferred and non-preferred leg in both barefoot and shod conditions. APA spatiotemporal parameters (size, duration, and speed) along both the anteroposterior and mediolateral axes were obtained through force plate data. APAs preceding lateral stepping showed typical patterns both along the anteroposterior and mediolateral axis. RM-ANOVA highlighted a significant effect of footwear only on medio-lateral APAs amplitude (p = 0.008) and velocity (p = 0.037). No differences were found for the limb preference. APAs in lateral stepping presented consistent features in the sagittal component, regardless of limb/shoe factors. Interestingly, the study observed that footwear induced an increase in the medio-lateral APAs size and velocity, highlighting the importance of including this factor when studying lateral stepping.

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