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).

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)

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.

scholarly journals Analysis of trunk muscle EMG during rotational motion

2021 ◽  
Author(s):  
Nika Zolfaghari
Keyword(s):  
Rotational Motion ◽  
Muscle Activity ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Wheelchair Users ◽  
Area Of Interest ◽  
Shoulder Muscles ◽  
Seated Balance ◽  
The Subject ◽  
Rotational Direction

The study of seated balance, specifically for the application of wheelchair users, has been an area of interest for quite some time. Unfortunately, most of the available studies to date have focused on upper limb and shoulder muscles, and little has been done analyzing the activity of trunk muscles (abdominal and back). For the purpose of this study, motorized rotational motion in the forward and backward directions at ±45 degrees was simulated, and the corresponding trunk muscle activity of nine healthy subjects was recorded by surface electromyography (EMG) for eight muscles, including an analysis on the effect of holding on to a harness for support, coupled with the presence of a visual input. The collected raw data was filtered, and the produced results illustrated that the muscle activity was greatest in the forward rotational direction, when the subject was holding on to a harness for support, with visuals present.

The Effects of Lifting Posture on Trunk Muscle Activity

1992 ◽  
Vol 36 (10) ◽  
pp. 742-746
Author(s):  
Christopher A. Hamrick ◽  
Sean Gallagher
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Oblique Muscle ◽  
Left And Right ◽  
External Oblique ◽  
Four Levels ◽  
The Right ◽  
Guidelines And Recommendations

Trunk muscle activity of twelve healthy males with coal mining experience was examined while each subject lifted a box under various conditions. The independent variables were four levels of posture (kneeling, stooped under a 1.2 m roof, stooped under a 1.6 m roof, and standing), height to which the box was lifted (35 cm or 70 cm), and weight of the lifting box (15 kg, 20 kg, or 25 kg). The dependent variables were the peak EMG values recorded during a lift for each of eight trunk muscles (left and right erectores spinae, left and right latissimus dorsi, left and right external oblique, and left and right rectus abdominis). Posture and weight of lift significantly affected peak activity of the left and right erectores spinae, the left and right latissimus dorsi muscles, and the right external oblique muscle. The latissimus dorsi muscle activity was highest in the low stooping posture, and was lowest in the kneeling posture, while erectores spinae activity was highest in the kneeling posture and decreased as the trunk became more flexed. Thus, the muscle activity during lifting tasks is affected by restricting a worker's posture. Consequently, many lifting guidelines and recommendations currently in use may not be directly applicable to work being performed in restricted postures.

Immediate changes in chest mobility and trunk muscle activity during pelvic tilt following different trunk muscle exercises

2021 ◽  
pp. 1-10
Author(s):  
Kazuma Uebayashi ◽  
Yu Okubo ◽  
Takuya Nishikawa ◽  
Taro Morikami ◽  
Jindo Hatanaka
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Abdominal Muscles ◽  
Kinematic Data ◽  
Repeated Measures Analysis ◽  
Before And After ◽  
Posterior Tilt ◽  
Increased Activity

BACKGROUND: Given the characteristics of the superficial trunk muscles that cross the chest and pelvis, their excessive contraction might limit chest mobility. OBJECTIVE: To examine the immediate effects of two types of trunk muscle exercises on chest mobility and trunk muscle activities. METHODS: Fourteen healthy men (age: 21.1 ± 1.0 years, height: 172.7 ± 5.6 cm, weight: 61.0 ± 7.1 kg, body mass index: 20.4 ± 1.7 kg/m2; mean ± SD) randomly performed trunk side flexion and draw-in exercises using a cross-over design. The chest kinematic data and trunk muscle activities were measured before and after each intervention during the following tasks: maximum inspiration/expiration and maximum pelvic anterior/posterior tilt while standing. Two-way repeated measures analysis of variance was used for statistical analysis (P< 0.05). RESULTS: After the side flexion, upper and lower chest mobility significantly decreased, and superficial trunk muscle activity significantly increased during the maximum pelvic anterior tilt (P< 0.05). Additionally, after the draw-in, upper chest mobility significantly increased during the maximum pelvic anterior tilt (P< 0.05). CONCLUSIONS: Increased activity of the superficial abdominal muscles might limit chest mobility during maximum pelvic anterior tilt. Conversely, the facilitation of deep trunk muscles might increase upper chest mobility during the maximum pelvic anterior tilt.

Validation and comparison of trunk muscle activities in male participants during exercise using an innovative device and abdominal bracing maneuvers

2021 ◽  
pp. 1-8
Author(s):  
Yuki Kurokawa ◽  
Satoshi Kato ◽  
Satoru Demura ◽  
Kazuya Shinmura ◽  
Noriaki Yokogawa ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Voluntary Contraction ◽  
Trunk Muscle ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Activity Levels ◽  
Significant Difference ◽  
External Oblique ◽  
Internal Oblique

BACKGROUND: Abdominal bracing is effective in strengthening the trunk muscles; however, assessing performance can be challenging. We created a device for performing abdominal trunk muscle exercises. The effectiveness of this device has not yet been evaluated or compared OBJECTIVE: We aimed to quantify muscle activity levels during exercise using our innovative device and to compare them with muscle activation during abdominal bracing maneuvers. METHODS: This study included 10 men who performed abdominal bracing exercises and exercises using our device. We measured surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique, internal oblique (IO), and erector spinae (ES) muscles in each of the exercises. The EMG data were normalized to those recorded during maximal voluntary contraction (%EMGmax). RESULTS: During the bracing exercise, the %EMGmax of IO was significantly higher than that of RA and ES (p< 0.05), whereas during the exercises using the device, the %EMGmax of IO was significantly higher than that of ES (p< 0.05). No significant difference was observed in the %EMGmax of any muscle between bracing exercises and the exercises using the device (p= 0.13–0.95). CONCLUSIONS: The use of our innovative device results in comparable activation to that observed during abdominal bracing.

scholarly journals Analysis of trunk muscle EMG during rotational motion

2021 ◽  
Author(s):  
Nika Zolfaghari
Keyword(s):  
Rotational Motion ◽  
Muscle Activity ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Wheelchair Users ◽  
Area Of Interest ◽  
Shoulder Muscles ◽  
Seated Balance ◽  
The Subject ◽  
Rotational Direction

The study of seated balance, specifically for the application of wheelchair users, has been an area of interest for quite some time. Unfortunately, most of the available studies to date have focused on upper limb and shoulder muscles, and little has been done analyzing the activity of trunk muscles (abdominal and back). For the purpose of this study, motorized rotational motion in the forward and backward directions at ±45 degrees was simulated, and the corresponding trunk muscle activity of nine healthy subjects was recorded by surface electromyography (EMG) for eight muscles, including an analysis on the effect of holding on to a harness for support, coupled with the presence of a visual input. The collected raw data was filtered, and the produced results illustrated that the muscle activity was greatest in the forward rotational direction, when the subject was holding on to a harness for support, with visuals present.

scholarly journals Single-Leg Squat Delicacies—The Position of the Nonstance Limb is an Important Consideration

2019 ◽  
Vol 28 (4) ◽  
pp. 318-324
Author(s):  
Benita Olivier ◽  
Samantha-Lynn Quinn ◽  
Natalie Benjamin ◽  
Andrew Craig Green ◽  
Jessica Chiu ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Inertial Sensors ◽  
Center Of Mass ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Trunk Flexion ◽  
Repeated Measures Design ◽  
Mass Displacement ◽  
Single Leg Squat

Context: The single-leg squat task is often used as a rehabilitative exercise or as a screening tool for the functional movement of the lower limb. Objective: To establish the effect of 3 different positions of the nonstance leg on 3-dimensional kinematics, muscle activity, and center of mass displacement during a single-leg squat. Design: Within-subjects, repeated-measures design. Setting: Movement analysis laboratory. Participants: A total of 10 participants, aged 28.2 (4.42) years performed 3 squats to 60° of knee flexion with the nonstance (1) hip at 90° flexion and knee at 90° flexion, (2) hip at 30° flexion with the knee fully extended, or (3) hip in neutral/0° and the knee flexed to 90°. Main Outcome Measures: Trunk, hip, knee and ankle joint angles, and center of mass displacement were recorded with inertial sensors while muscle activity was captured through wireless electromyography. Results: Most trunk flexion (21.38° [18.43°]) occurred with the nonstance hip at 90° and most flexion of the stance hip (23.10° [6.60°]) occurred with the nonstance hip at 0°. Biceps femoris activity in the 90° squat was 40% more than in the 0° squat, whereas rectus femoris activity in the 0° squat was 29% more than in the 90° squat. Conclusion: The position of the nonstance limb should be standardized when the single-leg squat is used for assessment and be adapted to the aim when used in rehabilitation.

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. 

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