scholarly journals Two aspects of feedforward postural control: anticipatory postural adjustments and anticipatory synergy adjustments

2011 ◽  
Vol 105 (5) ◽  
pp. 2275-2288 ◽  
Author(s):  
Miriam Klous ◽  
Pavle Mikulic ◽  
Mark L. Latash
Keyword(s):  
Muscle Activation ◽  
Center Of Pressure ◽  
Anticipatory Postural Adjustments ◽  
Uncontrolled Manifold ◽  
Trunk Muscles ◽  
Body Sway ◽  
Postural Adjustments ◽  
Muscle Mode ◽  
Shoulder Flexion ◽  
Muscle Modes

We used the framework of the uncontrolled manifold hypothesis to explore the relations between anticipatory synergy adjustments (ASAs) and anticipatory postural adjustments (APAs) during feedforward control of vertical posture. ASAs represent a drop in the index of a multimuscle-mode synergy stabilizing the coordinate of the center of pressure in preparation to an action. ASAs reflect early changes of an index of covariation among variables reflecting muscle activation, whereas APAs reflect early changes in muscle activation levels averaged across trials. The assumed purpose of ASAs is to modify stability of performance variables, whereas the purpose of APAs is to change magnitudes of those variables. We hypothesized that ASAs would be seen before APAs and that this finding would be consistent with regard to the muscle-mode composition defined on the basis of different tasks and phases of action. Subjects performed a voluntary body sway task and a quick, bilateral shoulder flexion task under self-paced and reaction time conditions. Surface muscle activity of 12 leg and trunk muscles was analyzed to identify sets of 4 muscle modes for each task and for different phases within the shoulder flexion task. Variance components in the muscle-mode space and indexes of multimuscle-mode synergy stabilizing shift of the center of pressure were computed. ASAs were seen ∼100–150 ms prior to the task initiation, before APAs. The results were consistent with respect to different sets of muscle modes defined over the two tasks and different shoulder flexion phases. We conclude that the preparation for a self-triggered postural perturbation is associated with two types of anticipatory adjustments, ASAs and APAs. They reflect different feedforward processes within the hypothetical hierarchical control scheme, resulting in changes in patterns of covariation of elemental variables and in their patterns averaged across trials, respectively. The results show that synergies quantified using dissimilar sets of muscle modes show similar feedforward changes in preparation to action.

scholarly journals A Novel Viewpoint on the Anticipatory Postural Adjustments During Gait Initiation

2021 ◽  
Vol 15 ◽  
Author(s):  
Veronica Farinelli ◽  
Francesco Bolzoni ◽  
Silvia Maria Marchese ◽  
Roberto Esposti ◽  
Paolo Cavallari
Keyword(s):  
Center Of Pressure ◽  
Force Plate ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Gait Initiation ◽  
Concentrated Force ◽  
Postural Adjustments ◽  
Leg Muscles

Anticipatory postural adjustments (APAs) are the coordinated muscular activities that precede the voluntary movements to counteract the associated postural perturbations. Many studies about gait initiation call APAs those activities that precede the heel-off of the leading foot, thus taking heel-off as the onset of voluntary movement. In particular, leg muscles drive the center of pressure (CoP) both laterally, to shift the body weight over the trailing foot and backward, to create a disequilibrium torque pushing forward the center of mass (CoM). However, since subjects want to propel their body rather than lift their foot, the onset of gait should be the CoM displacement, which starts with the backward CoP shift. If so, the leg muscles driving such a shift are the prime movers. Moreover, since the disequilibrium torque is mechanically equivalent to a forward force acting at the pelvis level, APAs should be required to link the body segments to the pelvis: distributing such concentrated force throughout the body would make all segments move homogeneously. In the aim of testing this hypothesis, we analyzed gait initiation in 15 right-footed healthy subjects, searching for activities in trunk muscles that precede the onset of the backward CoP shift. Subjects stood on a force plate for about 10 s and then started walking at their natural speed. A minimum of 10 trials were collected. A force plate measured the CoP position while wireless probes recorded the electromyographic activities. Recordings ascertained that at gait onset APAs develop in trunk muscles. On the right side, Rectus Abdominis and Obliquus Abdominis were activated in 11 and 13 subjects, respectively, starting on average 33 and 54 ms before the CoP shift; Erector Spinae (ES) at L2 and T3 levels was instead inhibited (9 and 7 subjects, 104 and 120 ms). On the contralateral side, the same muscles showed excitatory APAs (abdominals in 11 and 12 subjects, 27 and 82 ms; ES in 10 and 7 subjects, 75 and 32 ms). The results of this study provide a novel framework for distinguishing postural from voluntary actions, which may be relevant for the diagnosis and rehabilitation of gait disorders.

scholarly journals The Effects of Abdominal Hypopressive Training on Postural Control and Deep Trunk Muscle Activation: A Randomized Controlled Trial

2021 ◽  
Vol 18 (5) ◽  
pp. 2741
Author(s):  
María del Mar Moreno-Muñoz ◽  
Fidel Hita-Contreras ◽  
María Dolores Estudillo-Martínez ◽  
Agustín Aibar-Almazán ◽  
Yolanda Castellote-Caballero ◽  
...  
Keyword(s):  
Postural Control ◽  
Muscle Activation ◽  
Center Of Pressure ◽  
Controlled Trial ◽  
Trunk Muscle ◽  
Posture Control ◽  
Trunk Muscles ◽  
Control Group ◽  
Female Population ◽  
Imaging Results

Background: Abdominal Hypopressive Training (AHT) provides postural improvement, and enhances deep trunk muscle activation. However, until recently, there was a lack of scientific literature supporting these statements. The major purpose of this study was to investigate the effect of AHT on posture control and deep trunk muscle function. Methods: 125 female participants aged 18–60 were randomly allocated to the Experimental Group (EG), consisting of two sessions of 30 min per week for 8 weeks of AHT, or the Control Group (CG), who did not receive any treatment. Postural control was measured with a stabilometric platform to assess the static balance and the activation of deep trunk muscles (specifically the Transverse Abdominal muscle (TrA)), which was measured by real-time ultrasound imaging. Results: The groups were homogeneous at baseline. Statistical differences were identified between both groups after intervention in the Surface of the Center of Pressure (CoP) Open-Eyes (S-OE) (p = 0.001, Cohen’s d = 0.60) and the Velocity of CoP under both conditions; Open-Eyes (V-OE) (p = 0.001, Cohen´s d = 0.63) and Close-Eyes (V-CE) (p = 0.016, Cohen´s d = 0.016), with the EG achieving substantial improvements. Likewise, there were statistically significant differences between measurements over time for the EG on S-OE (p < 0.001, Cohen´s d = 0.99); V-OE (p = 0.038, Cohen´s d = 0.27); V-CE (p = 0.006, Cohen´s d = 0.39), anteroposterior movements of CoP with Open-Eyes (RMSY-OE) (p = 0.038, Cohen´s d = 0.60) and activity of TrA under contraction conditions (p < 0.001, Cohen´s d = 0.53). Conclusions: The application of eight weeks of AHT leads to positive outcomes in posture control, as well as an improvement in the deep trunk muscle contraction in the female population.

Adaptive Changes in Anticipatory Postural Adjustments With Novel and Familiar Postural Supports

2010 ◽  
Vol 103 (2) ◽  
pp. 968-976 ◽  
Author(s):  
Leanne M. Hall ◽  
Sandra Brauer ◽  
Fay Horak ◽  
Paul W. Hodges
Keyword(s):  
Center Of Pressure ◽  
Anticipatory Postural Adjustments ◽  
Pressure Amplitude ◽  
Postural Adjustments ◽  
Bite Plate ◽  
Reaction Forces ◽  
Multiple Support ◽  
Vertical Ground ◽  
Postural Support ◽  
Vertical Ground Reaction Forces

Anticipatory postural adjustments (APAs) serve to stabilize posture prior to initiation of voluntary movement. This study examined the effects of changes in postural support on APAs using novel and familiar support paradigms. We also investigated whether postural strategies were refined with practice and how the CNS responded when multiple supports were available. Twelve healthy subjects stood on dual force platforms and performed 20 randomized left and right rapid leg-lift tasks in response to a visual cue under four conditions: unsupported, bilateral handgrip, bite plate, and a combined handgrip and bite plate condition. Vertical ground reaction forces, electromyography of limb, trunk and jaw muscles, and forces exerted on the support apparatus were recorded. Shift in center-of-pressure amplitude and duration were reduced with increased support. Muscles were recruited in advance of the focal movement when able to contribute to stability, and activity was modulated based on the amount of support available. The CNS adapted anticipatory postural strategies immediately with changes in condition regardless of familiarity with the support; however, adaptation was only complete at the first repetition in conditions that involved familiar support strategies. Tasks that involved a novel bite strategy continued to adapt with practice. In the multiple support condition, both hand and bite strategies were immediately incorporated; however, the contribution of each was not identical to conditions where supports were provided individually. This study emphasizes the flexibility of the CNS to organize postural strategies to meet the demands of postural stability in both familiar and novel situations.

scholarly journals Balance Control and Muscles Activity of An Elderly Retired Man During Different Focus of Attention Instructions

2020 ◽  
Vol 13 (1) ◽  
pp. 129-136
Author(s):  
Amin Amini ◽  
Hossein Shirvani ◽  
Behzad Bazgir
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Center Of Pressure ◽  
Balance Control ◽  
Focus Of Attention ◽  
Body Sway ◽  
Triceps Brachii ◽  
External Focus

Background: Good balance and muscle activity are essential to do daily activities. Recent studies have focused on the relations between balance and attention patterns. The study of the balance and muscle activity of people in different patterns of attention can clarify the nature of the effect of attention instructions. Purpose: The present study aims to evaluate the changes in different focus of attention instructions and quality of balance control and muscle activity in the elderly retired. Methods: Thirty elderly retired men [mean age: 51.6 ± 6.4 years] were recruited for this study. Subjects were selected through the berg balance test. Balance control ability [Biodex Balance System] and muscle activity [electromyography system] were assessed in two conditions, internal attention and external attention task. The data obtained were analyzed using repeated-measures ANOVA at a significant level of P<0.05. Results: Body sway and muscle activity parameters were correlated with different patterns of attention. During external focus condition, [1] Center of Pressure [CoP] total two-leg balance, CoP medio-lateral and CoP anterior-posterior for external-focus were lowered [P<0.05] and [2] Tibialis anterior and soleus for the leg, biceps brachii and triceps brachii for the arm, sternocleidomastoid and semispinalis capitis for external-focus were lowered [P<0.05]. Conclusion: Improved static balance responses and alterations in postural control were observed under external focus conditions. An external focus of attention may be the preferred method for facilitating balance control and muscle activation in an elderly retired man.

scholarly journals EMG Analysis of Trunk Muscle Recruitment Patterns of Anticipatory Postural Adjustments during Unilateral Arm Flexion in Chronic Neck Pain Patients

2018 ◽  
Author(s):  
F Ghaffarinejad ◽  
A Kordi Yoosefinejad ◽  
S Pirouzi ◽  
A R Shakibafar ◽  
Z Bagheri ◽  
...  
Keyword(s):  
Neck Pain ◽  
Chronic Neck Pain ◽  
Anticipatory Postural Adjustments ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Repeated Measure ◽  
Control Group ◽  
Onset Latency ◽  
Postural Adjustments ◽  
Recruitment Patterns

Introduction: EMG recruitment pattern of trunk muscles can change to compensate pain. One of these pattern alterations occurs in anticipatory postural adjustments (APAs) or feedforward activity of trunk muscles prior to arm movements. No study has determined the EMG pattern alterations of trunk muscle recruitments during the arm movement in patients with chronic neck pain (CNP). This study was examined the effect of CNP on EMG activities of trunk muscles for APAs during rapid arm flexion. Material and Methods: Sixteen patients with CNP for at least 3 months and sixteen healthy individuals matched in gender, age and weight were selected in this semi-experimental study. Surface EMG was utilized to evaluate 8 trunk muscles bilaterally and right anterior fibers of deltoid muscle during a unilateral rapid arm flexion. Anticipatory muscle activity was calculated by EMG onset latency of the trunk muscle from 100 ms before deltoid activity to 100 ms after it. Also, the values of root mean square (RMS) in 4 epochs around the onset of deltoid EMG were measured and compared. A two-tailed t-test and repeated-measure ANOVA were used for statistical analyses.Results: The onset latency of muscles in left and right side, except left erector spine muscle, in patients showed a significantly higher delay compared to healthy controls (P<0.05). The analysis of RMS in the 4 epochs revealed that in the control group, the values of RMS for rectus abdominus and erector spine in both sides, left external oblique and left transverse abdominus/internal oblique increased significantly during Epochs 3 and 4 , but in CNP subjects, the RMS of these muscles did not change significantly in 4 epochs.Conclusion: The patients with CNP had alterations in their recruitment patterns of particular trunk muscles in response to arm movement.Therefore, these patients have impaired motor control of trunk muscles during internal perturbation. These results indicated that not only the alterations in recruitment of trunk muscles occur, but also the intensity of their contractions decreases. In conclusion, CNP may alter in order to control the reactive forces resulting from limb movement. 

15.6 Anticipatory postural adjustments during shoulder flexion in Parkinson's disease and influence of levodopa

2005 ◽  
Vol 21 ◽  
pp. S91-S92
Author(s):  
S. Bleuse ◽  
L. Defebvre ◽  
F. Cassim ◽  
J.-L. Blatt ◽  
E. Labyt ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Anticipatory Postural Adjustments ◽  
Postural Adjustments ◽  
Shoulder Flexion

scholarly journals Effects of Fourteen-Day Bed Rest on Trunk Stabilizing Functions in Aging Adults

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Nejc Sarabon ◽  
Jernej Rosker
Keyword(s):  
Arm Movement ◽  
Bed Rest ◽  
Complete Recovery ◽  
Anticipatory Postural Adjustments ◽  
Trunk Muscles ◽  
Significant Deterioration ◽  
Response Latencies ◽  
Postural Adjustments ◽  
Postural Reflex ◽  
Aging Adults

Bed rest has been shown to have detrimental effects on structural and functional characteristics of the trunk muscles, possibly affecting trunk and spinal stability. This is especially important in populations such as aging adults with often altered trunk stabilizing functions. This study examined the effects of a fourteen-day bed rest on anticipatory postural adjustments and postural reflex responses of the abdominal wall and back muscles in sixteen adult men. Postural activation of trunk muscles was measured using voluntary quick arm movement and sudden arm loading paradigm. Measurements were conducted prior to the bed rest, immediately after, and fourteen days after the bed rest. Immediately after the bed rest, latencies of anticipatory postural adjustments showed significant shortening, especially for the obliquus internus and externus muscles. After a fourteen-day recuperation period, anticipatory postural adjustments reached a near to complete recovery. On the contrary, reactive response latencies increased from pre-bed-rest to both post-bed-rest measurement sessions. Results indicate an important effect of bed rest on stabilizing functions of the trunk muscles in elderly adults. Moreover, there proved to be a significant deterioration of postural reactive responses that outlasted the 14-day post-bed-rest rehabilitation.

scholarly journals Effect of dance on multi-muscle synergies in older adults: a cross-sectional study

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Yun Wang ◽  
Kazuhiko Watanabe ◽  
Tadayoshi Asaka
Keyword(s):  
Older Adults ◽  
Muscle Activation ◽  
Center Of Pressure ◽  
Balance Training ◽  
Uncontrolled Manifold ◽  
Control Group ◽  
Muscle Synergies ◽  
Support Surface ◽  
Cross Sectional ◽  
Step Initiation

Abstract Background The purpose of this study was to investigate the efficacy of dance in the experienced older dancers compared to the inexperienced older adults. We explored the effect of dance on the composition of muscle groups and multi-muscle synergies stabilizing the center of pressure (COP) displacement in preparation to take a step during support surface translation. Methods Eight dance experienced elderly participants were asked to take a step in response to support surface perturbations. Uncontrolled manifold analysis was used to identify muscle modes (M-modes) as factors in the muscle activation space. Variance components in the M-mode space and indices of M-mode synergy stabilizing COP displacement were computed. Results The reciprocal M-modes were observed more frequently in the dance group than in the control group prior to the step initiation. Dance led to higher indices of multi-muscle synergies and earlier anticipatory synergy adjustments during preparation for making a step in response to the support surface translations. Conclusions Dance appeared to be associated with adjustments in both the composition of M-modes and M-mode co-variation patterns resulting in stronger synergies stabilizing COP coordinate in older adults. The results reported here could have clinical relevance when offering a dance approach to balance training for impaired individuals.

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