Human automatic postural responses: responses to horizontal perturbations of stance in multiple directions

1988 ◽  
Vol 73 (3) ◽  
pp. 648-658 ◽  
Author(s):  
S. P. Moore ◽  
D. S. Rushmer ◽  
S. L. Windus ◽  
L. M. Nashner
Keyword(s):  
Postural Responses ◽  
Automatic Postural Responses

Modification of postural responses and step initiation: evidence for goal-directed postural interactions

1994 ◽  
Vol 72 (6) ◽  
pp. 2892-2902 ◽  
Author(s):  
A. L. Burleigh ◽  
F. B. Horak ◽  
F. Malouin
Keyword(s):  
External Perturbation ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Original Position ◽  
Foot Pressure ◽  
Postural Adjustments ◽  
Step Initiation ◽  
Postural Responses ◽  
Surface Translation ◽  
Automatic Postural Responses

1. In this study, the interaction between anticipatory postural adjustments for step initiation and automatic postural responses to an external perturbation were investigated by having subjects initiate a voluntary forward step while perturbed by a backward surface translation, which caused forward sway of the body. The postural adjustments for step initiation act to move the body center of mass (COM) forward, whereas the automatic postural responses act to move the COM backward to restore stance equilibrium. Because the postural behaviors are in opposition, we asked whether a temporal hierarchy exists in which automatic postural responses are executed to restore equilibrium and followed by stereotypic postural adjustments for step initiation, or whether the interaction between these two postural behaviors is more dynamic. 2. Lower extremity electromyographs (EMGs), ground reaction forces, and kinematics were recorded from 10 subjects during three conditions: to quantify the anticipatory postural adjustments for step initiation, subjects stepped forward as soon as they felt a proprioceptive cue; to quantify the automatic postural responses to perturbation, subjects maintained stance equilibrium in response to a backward surface translation under both feet; and to quantify the interaction between the postural adjustments for the voluntary step and the automatic responses to the perturbation, subjects were exposed to a backward surface translation and instructed to step forward as soon as they felt the platform begin to move. 3. The anticipatory adjustments for step initiation included tibialis activation [stance limb = 163 +/- 28 (SE) ms; swing limb = 173 +/- 33 ms] and soleus inhibition resulting in center of foot pressure (COP) moving backward and lateral toward the swing limb to propel the COM forward over the stance limb. Subsequently, activation of the swing limb gastrocnemius resulted in heel-off. In contrast, the automatic postural adjustments for maintenance of stance equilibrium during a backward surface translation included activation of soleus and gastrocnemius (104 +/- 23 ms and 115 +/- 14 ms, respectively) resulting in a symmetrical forward displacement of the COP that moved the COM back to its original position with respect to the feet. 4. When a forward step was initiated in response to the translation, the automatic postural responses were reduced in amplitude bilaterally in soleus and in the stance limb gastrocnemius. When present the postural response occurred at the same latency when the goal was to initiate a step as when the goal was to maintain standing.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Improvement in Automatic Postural Coordination Following Alexander Technique Lessons in a Person With Low Back Pain

2005 ◽  
Vol 85 (6) ◽  
pp. 565-578 ◽  
Author(s):  
Timothy W Cacciatore ◽  
Fay B Horak ◽  
Sharon M Henry
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Force Plate ◽  
Muscular Activity ◽  
Alexander Technique ◽  
Low Back ◽  
Postural Coordination ◽  
Postural Responses ◽  
History Of ◽  
Automatic Postural Responses

Abstract Background and Purpose. The relationship between abnormal postural coordination and back pain is unclear. The Alexander Technique (AT) aims to improve postural coordination by using conscious processes to alter automatic postural coordination and ongoing muscular activity, and it has been reported to reduce low back pain. This case report describes the use of the AT with a client with low back pain and the observed changes in automatic postural responses and back pain. Case Description. The client was a 49-year-old woman with a 25-year history of left-sided, idiopathic, lumbrosacral back pain. Automatic postural coordination was measured using a force plate during horizontal platform translations and one-legged standing. Outcomes. The client was tested monthly for 4 months before AT lessons and for 3 months after lessons. Before lessons, she consistently had laterally asymmetric automatic postural responses to translations. After AT lessons, the magnitude and asymmetry of her responses and balance improved and her low back pain decreased. Discussion. Further research is warranted to study whether AT lessons improve low back pain-associated abnormalities in automatic postural coordination and whether improving automatic postural coordination helps to reduce low back pain.

Modulations of Muscle Modes in Automatic Postural Responses Induced by External Surface Translations

2011 ◽  
Vol 43 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Tadayoshi Asaka ◽  
Kentaro Yahata ◽  
Hiroki Mani ◽  
Yun Wang
Keyword(s):  
External Surface ◽  
Postural Responses ◽  
Automatic Postural Responses ◽  
Muscle Modes

Author response for "Automatic postural responses are scaled from the association between online feedback and feedforward control"

2019 ◽  
Author(s):  
Luis Augusto Teixeira ◽  
Nametala Maia Azzi ◽  
Júlia Ávila de Oliveira ◽  
Caroline Ribeiro de Souza ◽  
Lucas da Silva Rezende ◽  
...  
Keyword(s):  
Feedforward Control ◽  
Author Response ◽  
Postural Responses ◽  
Online Feedback ◽  
Automatic Postural Responses

Author response for "Automatic postural responses are scaled from the association between online feedback and feedforward control"

2019 ◽  
Author(s):  
Luis Augusto Teixeira ◽  
Nametala Maia Azzi ◽  
Júlia Ávila de Oliveira ◽  
Caroline Ribeiro de Souza ◽  
Lucas da Silva Rezende ◽  
...  
Keyword(s):  
Feedforward Control ◽  
Author Response ◽  
Postural Responses ◽  
Online Feedback ◽  
Automatic Postural Responses

Influence of instruction, prediction, and afferent sensory information on the postural organization of step initiation

1996 ◽  
Vol 75 (4) ◽  
pp. 1619-1628 ◽  
Author(s):  
A. Burleigh ◽  
F. Horak
Keyword(s):  
Anticipatory Postural Adjustments ◽  
Postural Response ◽  
Postural Adjustments ◽  
Automatic Postural Response ◽  
Step Initiation ◽  
Postural Responses ◽  
Automatic Response ◽  
Perturbation Velocity ◽  
Velocity Information ◽  
Automatic Postural Responses

1. Our previous study showed that two distinct postural modifications occurred when subjects were instructed to step, rather than maintain stance, in response to a backward surface translation: 1) the automatic postural responses to the surfaces perturbation were reduced in magnitude and 2) the anticipatory postural adjustments promoting foot-off were shortened in duration. This study investigates the extent to which task instruction, prediction of perturbation velocity, and afferent sensory information related to perturbation velocity are responsible for these postural modification. 2. Eleven human subjects were instructed in advance, to either maintain stance or step forward in response to a backward surface translation. Four different velocities of translation were used to perturb equilibrium. To assess the influence of predicted versus actual velocity information, the surface translations were presented in both a blocked order of increasing perturbation velocity (predictable) and a random order (unpredictable). Lower-extremity electromyographs (EMGs), ground reaction forces, and movement kinematics were quantified for both the automatic postural responses to perturbation and the anticipatory postural adjustments for step initiation. 3. The instruction to step was not solely responsible for the suppression of the automatic postural response. Prediction of perturbation velocity was required for significant suppression of the early automatic postural response when subjects stepped in response to the perturbation. When compared with the stance condition, the magnitude of the initial 50 ms of the automatic response in bilateral soleus and the left limb gastrocnemius (initial stance limb) was significantly reduced only when the perturbation velocities were presented in a blocked order. The magnitude of the automatic response was not reduced in the gastrocnemius of the right limb, which was always the initial swing limb and recruited for heel-off in the step conditions. This asymmetrical reduction of the gastrocnemius suggests that modification of the response was specific to the instruction, rather than a general decrease in the extensor muscle excitability. 4. The suppression of the early automatic postural response involved a change in the bias of the response. Despite the reduced magnitude during the predictable velocity step condition, the slope (i.e., gain) of the response with increasing velocities was not different from that of the stance condition. Thus the excitability of the automatic response was reduced by a relatively constant amount for each velocity when the perturbation velocity was predictable. 5. In contrast to the importance of velocity prediction for modification of the automatic postural response, actual velocity information was used for modification of the anticipatory postural adjustments when step was initiated in response to the surface perturbation. Regardless of whether the perturbation velocities were presented in a blocked or random order, the anticipatory postural adjustments were rapidly initiated and the duration of the postural adjustments for step initiation was shortened as the velocity of perturbation increased. 6. We conclude that the CNS uses prediction of perturbation velocity to modify the excitability of early automatic postural responses when the postural goal changes. In contrast, actual afferent velocity information can be used to modify the duration of the anticipatory postural adjustments for a voluntary step in response to perturbation. Thus the CNS utilizes feed-forward prediction to modify peripherally triggered postural responses, and utilizes immediate afferent information to modify the centrally initiated postural adjustments associated with voluntary movement.

Influence of auditory precuing on automatic postural responses

1996 ◽  
Vol 108 (2) ◽  
Author(s):  
J.W. McChesney ◽  
H. Sveistrup ◽  
M.H. Woollacott
Keyword(s):  
Postural Responses ◽  
Automatic Postural Responses

scholarly journals The Effect of Adaptation and Expectation on Initial Stances Prior to Automatic Postural Responses.

2001 ◽  
Vol 13 (2) ◽  
pp. 93-98
Author(s):  
Hiroshi Maejima ◽  
Chie Kamoda ◽  
Tatehito Ueda ◽  
Hisato Sasaki ◽  
Sachiko Tanaka ◽  
...  
Keyword(s):  
Postural Responses ◽  
Automatic Postural Responses
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