Individuals With Stroke Use Asymmetrical Anticipatory Postural Adjustments When Counteracting External Perturbations

Motor Control ◽  
2019 ◽  
Vol 23 (4) ◽  
pp. 461-471
Author(s):  
Etem Curuk ◽  
Yunju Lee ◽  
Alexander S. Aruin
Keyword(s):  
Muscle Activity ◽  
Balance Control ◽  
Anticipatory Postural Adjustments ◽  
Trunk Muscles ◽  
Electromyographic Activity ◽  
Healthy Controls ◽  
Unaffected Side ◽  
Postural Adjustments ◽  
External Perturbations ◽  
Anticipatory Activation

The authors investigated anticipatory postural adjustments in persons with unilateral stroke using external perturbations. Nine individuals with stroke and five control subjects participated. The electromyographic activity of 16 leg and trunk muscles was recorded. The onsets of muscle activity during the anticipatory phase of postural control were analyzed. The individuals with stroke did not show an anticipatory activation of leg and trunk muscles on the affected side; instead, the muscle onsets were seen after the perturbation, during the balance restoration phase. However, an anticipatory activation of muscles on the unaffected side was seen in individuals with stroke, and it was observed earlier compared with healthy controls (p < .05). The individuals with stroke showed a distal to proximal order of anticipatory activation of muscles on the unaffected side. The outcome of the study provides a basis for future investigations regarding ways of improving balance control in people with stroke.

scholarly journals Effects of External Perturbations on Anticipatory and Compensatory Postural Adjustments in Patients with Multiple Sclerosis and a Fall History

2018 ◽  
Vol 20 (4) ◽  
pp. 164-172 ◽  
Author(s):  
Shirin Tajali ◽  
Mina Rouhani ◽  
Mohammad Mehravar ◽  
Hossein Negahban ◽  
Elham Sadati ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Fall Prevention ◽  
Muscle Activity ◽  
Center Of Pressure ◽  
Trunk Muscles ◽  
Postural Adjustment ◽  
Postural Adjustments ◽  
External Perturbations ◽  
The Relationship ◽  
Adjustment Mechanisms

Abstract Background: Although previous studies have investigated postural adjustment mechanisms in patients with multiple sclerosis (MS), it seems that no study has yet investigated the relationship between anticipatory and compensatory postural adjustments (APAs and CPAs, respectively) and falls. Methods: Seventeen MS fallers, 17 MS nonfallers, and 15 controls were exposed to a series of expected and unexpected backward pull perturbations applied at the trunk level. The electrical activity of 12 leg and trunk muscles as well as center of pressure displacement were recorded. Results: The MS fallers had delayed muscle activity onsets compared with MS nonfallers and controls. In addition, a significantly lower level of muscle activity during APAs was detected in MS fallers compared with controls. Moreover, in the unexpected condition of perturbation, significantly smaller CPA was observed in MS fallers compared with controls. Both groups of patients with MS required more time to stabilize their center of pressure after both types of perturbations compared with controls. Conclusions: The inability to produce efficient APAs and CPAs during perturbations may explain the high rates of postural instability and falls in patients with MS. Findings from this study provide a background for the development of perturbation-based training programs aimed at balance improvement and fall prevention by restoring mechanisms underlying balance impairments.

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)

Decoupling of stretch reflex and background muscle activity during anticipatory postural adjustments in humans

2010 ◽  
Vol 205 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Siddharth Vedula ◽  
Robert E. Kearney ◽  
Ross Wagner ◽  
Paul J. Stapley
Keyword(s):  
Muscle Activity ◽  
Stretch Reflex ◽  
Anticipatory Postural Adjustments ◽  
Postural Adjustments

scholarly journals Evaluation of gait initiation parameters using inertial sensors in Huntington's Disease: Insights into anticipatory postural adjustments and cognitive interference

2020 ◽  
Author(s):  
Radhika Desai ◽  
Nora E Fritz ◽  
Lisa Muratori ◽  
Jeffrey M. Hausdorff ◽  
Lori Quinn
Keyword(s):  
Cognitive Load ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Gait Speed ◽  
Load Condition ◽  
Anticipatory Postural Adjustments ◽  
Gait Initiation ◽  
Healthy Controls ◽  
Postural Adjustments ◽  
Single Task

Background and Purpose: Understanding the contribution of anticipatory postural adjustments (APA) on walking ability in individuals with Huntington's disease (HD) may provide insight into motor planning and the functional consequences of HD-specific cortical-basal ganglia pathway dysfunctions. The purpose of this study was to evaluate inertial measurement unit (IMU)-derived measures of APAs and first step parameters, and their contribution to gait speed, in individuals with and without manifest HD during a single-task and cognitive load condition. Methods: 33 individuals with manifest HD and 15 age-matched healthy controls wore three Opal APDM IMUs during a 14-meter walk during a single task and cognitive load condition. APA acceleration amplitudes, APA durations, first step range of motion (ROMs), and first step duration were compared, along with their relationship to gait speed. Results: Individuals with HD had significantly greater APA acceleration amplitudes, smaller first step ROMs and longer first step durations compared to healthy controls. No difference in APA durations were present between groups across conditions. Linear model results and significant correlations between mediolateral APA acceleration amplitudes and APA durations were found. Conclusions: Larger acceleration amplitudes, smaller first step ROMs of greater duration, accompanied by the preservation of APA durations reveal a discrepancy in movement scaling in HD. Additionally, the mediolateral component of the APA is likely a rate-limiting factor that drives a compensatory response in gait initiation. Additional research is needed to explore the neural correlates of HD-related movement scaling.

Electromyographic Activity of Trunk Muscles During Flexion-Distraction Treatment of Low Back Patients

1999 ◽  
Author(s):  
Maruti R. Gudavalli ◽  
Jerrilyn A. Backman ◽  
Steven J. Kirstukas ◽  
Anant V. Kadiyala ◽  
Avinash G. Patwardhan ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Low Back ◽  
Mean Values ◽  
Flexion Extension ◽  
Left And Right ◽  
The Mean

Abstract The objective of this study was to determine the electromyographic (EMG) activity of the superficial muscles during the treatment of low back patients during a conservative procedure known as the Cox flexion-distraction procedure. A total of 33 low back pain patients were recruited for this study from chiropractic and allopathic orthopedic clinics. EMG signals were collected while the patient was in a prone relaxed position, during the treatment using the flexion-distraction procedure, and during maximum voluntary exertions in the three planes (flexion, extension, left and right lateral bending, and left and right twisting). The mean values of the Root Mean Square (RMS) values of EMG ratios during treatment versus resting indicate that the muscles are active during the treatment. This activity is more than the activity at rest. However the mean values of the RMS EMG ratios (during treatment versus maximum voluntary contraction) are small indicating that the muscle activity during treatment may not influence the treatment loads. The left and right muscles in all muscle groups were similarly active. During the treatment, erector spinae muscles were the most active, followed by the external oblique, and the rectus abdominus muscles. The results from this study provide quantitative data for the muscle activity during the flexion-distraction treatment. This information can be incorporated into computer models to estimate the loads generated during the flexion-distraction treatment due to the muscle activity compared to the loads generated by the chiropractic physician.

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 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. 

Evidence for constancy in the modularity of trunk muscle activity preceding reaching: Implications for the role of preparatory postural activity.

2021 ◽  
Author(s):  
Alexander Stamenkovic ◽  
Lena H Ting ◽  
Paul J Stapley
Keyword(s):  
Muscle Activity ◽  
Center Of Mass ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Equilibrium Constraints ◽  
Postural Adjustments ◽  
Postural Activity ◽  
Postural Muscle ◽  
Mass Displacement ◽  
Base Of Support

Postural muscle activity precedes voluntary movements of the upper limbs. The traditional view of this activity is that it anticipates perturbations to balance caused by the movement of a limb. However, findings from reach-based paradigms have shown that postural adjustments can initiate center of mass displacement for mobility, rather than minimize its displacement for stability. Within this context, altering reaching distance beyond the base of support would place increasing constraints on equilibrium during stance. If the underlying composition of anticipatory postural activity is linked to stability, coordination between muscles (i.e., motor modules) may evolve differently as equilibrium constraints increase. We analyzed the composition of motor modules in functional trunk muscles as participants performed multi-directional reaching movements to targets within and beyond arm's length. Bilateral trunk and reaching arm muscle activity were recorded. Despite different trunk requirements necessary for successful movement, and the changing biomechanical (i.e. postural) constraints that accompany alterations in reach distance, Non-negative Matrix Factorization identified functional motor modules derived from preparatory trunk muscle activity that shared common features. Relative similarity in modular weightings (i.e., composition) and spatial activation profiles that reflect movement goals across tasks necessitating differing levels of trunk involvement provides evidence that preparatory postural adjustments are linked to the same task priorities (i.e. movement generation rather than stability).

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.

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