Time-dependent directional intermuscular coherence analysis reveals that forward and backward arm swing equally drive the upper leg muscles during gait initiation

Background: The supplementary motor area (SMA) is implicated in both motor initiation and stereotypic multi-limb movements such as walking with arm swing. Gait in Parkinson’s disease exhibits starting difficulties and reduced arm swing, consistent with reduced SMA activity. Objective: We tested whether enhanced arm swing could improve Parkinson gait initiation and assessed whether increased SMA activity during preparation might facilitate such improvement. Methods: Effects of instructed arm swing on cortical activity, muscle activity and kinematics were assessed by ambulant EEG, EMG, accelerometers and video in 17 Parkinson patients and 19 controls. At baseline, all participants repeatedly started walking after a simple auditory cue. Next, patients started walking at this cue, which now meant starting with enhanced arm swing. EEG changes over the putative SMA and leg motor cortex were assessed by event related spectral perturbation (ERSP) analysis of recordings at Fz and Cz. Results: Over the putative SMA location (Fz), natural PD gait initiation showed enhanced alpha/theta synchronization around the auditory cue, and reduced alpha/beta desynchronization during gait preparation and movement onset, compared to controls. Leg muscle activity in patients was reduced during preparation and movement onset, while the latter was delayed compared to controls. When starting with enhanced arm swing, these group differences virtually disappeared. Conclusion: Instructed arm swing improves Parkinson gait initiation. ERSP normalization around the cue indicates that the attributed information may serve as a semi-internal cue, recruiting an internalized motor program to overcome initiation difficulties.

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20.21 Taï chi practice reduces leg muscles co-activation during gait initiation in elders

Gait & Posture ◽

10.1016/s0966-6362(05)80435-7 ◽

2005 ◽

Vol 21 ◽

pp. S132

Author(s):

T. Lelard ◽

I. Mora ◽

P.L. Doutrellot ◽

S. Ahmaidi

Keyword(s):

Tai Chi ◽

Gait Initiation ◽

Leg Muscles ◽

Co Activation

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Anticipatory postural adjustments of gait initiation affected by proprioceptive alterations of lower leg muscles

Gait & Posture ◽

10.1016/j.gaitpost.2021.09.063 ◽

2021 ◽

Vol 90 ◽

pp. 123

Author(s):

J. Kimijanova ◽

D. Bzduskova ◽

Z. Hirjakova ◽

F. Hlavacka

Keyword(s):

Lower Leg ◽

Anticipatory Postural Adjustments ◽

Gait Initiation ◽

Postural Adjustments ◽

Leg Muscles

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Control strategy of maximum vertical jumps: The preferred countermovement depth may not be fully optimized for jump height

Journal of Human Kinetics ◽

10.1515/hukin-2015-0196 ◽

2016 ◽

Vol 52 (1) ◽

pp. 85-94 ◽

Cited By ~ 10

Author(s):

Radivoj Mandic ◽

Olivera M. Knezevic ◽

Dragan M. Mirkov ◽

Slobodan Jaric

Keyword(s):

Control Strategy ◽

Power Output ◽

Jump Height ◽

Basketball Players ◽

Physically Active ◽

Arm Swing ◽

Testing Procedures ◽

Leg Muscles ◽

Task Strategy ◽

Vertical Jumps

Abstract The aim of the present study was to explore the control strategy of maximum countermovement jumps regarding the preferred countermovement depth preceding the concentric jump phase. Elite basketball players and physically active non-athletes were tested on the jumps performed with and without an arm swing, while the countermovement depth was varied within the interval of almost 30 cm around its preferred value. The results consistently revealed 5.1-11.2 cm smaller countermovement depth than the optimum one, but the same difference was more prominent in non-athletes. In addition, although the same differences revealed a marked effect on the recorded force and power output, they reduced jump height for only 0.1-1.2 cm. Therefore, the studied control strategy may not be based solely on the countermovement depth that maximizes jump height. In addition, the comparison of the two groups does not support the concept of a dual-task strategy based on the trade-off between maximizing jump height and minimizing the jumping quickness that should be more prominent in the athletes that routinely need to jump quickly. Further research could explore whether the observed phenomenon is based on other optimization principles, such as the minimization of effort and energy expenditure. Nevertheless, future routine testing procedures should take into account that the control strategy of maximum countermovement jumps is not fully based on maximizing the jump height, while the countermovement depth markedly confound the relationship between the jump height and the assessed force and power output of leg muscles.

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A Novel Viewpoint on the Anticipatory Postural Adjustments During Gait Initiation

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.709780 ◽

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.

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Age-Related Changes of the Anticipatory Postural Adjustments During Gait Initiation Preceded by Vibration of Lower Leg Muscles

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.771446 ◽

2021 ◽

Vol 15 ◽

Author(s):

Jana Kimijanová ◽

Diana Bzdúšková ◽

Zuzana Hirjaková ◽

František Hlavačka

Keyword(s):

Older Adults ◽

Sagittal Plane ◽

Balance Control ◽

The Elderly ◽

Lower Leg ◽

Anticipatory Postural Adjustments ◽

The Body ◽

Gait Initiation ◽

Leg Muscles ◽

Age Related

Gait initiation (GI) challenges the balance control system, especially in the elderly. To date, however, there is no consensus about the age effect on the anticipatory postural adjustments (APAs). There is also a lack of research on APAs in older adults after proprioceptive perturbation in the sagittal plane. This study aimed to compare the ability of young and older participants to generate APAs in response to the vibratory-induced perturbation delivered immediately before GI. Twenty-two young and 22 older adults performed a series of GI trials: (1) without previous vibration; (2) preceded by the vibration of triceps surae muscles; and (3) preceded by the vibration of tibialis anterior muscles. The APAs magnitude, velocity, time-to-peak, and duration were extracted from the center of pressure displacement in the sagittal plane. Young participants significantly modified their APAs during GI, whereas older adults did not markedly change their APAs when the body vertical was shifted neither backward nor forward. Significant age-related declines in APAs were observed also regardless of the altered proprioception.The results show that young adults actively responded to the altered proprioception from lower leg muscles and sensitively scaled APAs according to the actual position of the body verticality. Contrary, older adults were unable to adjust their postural responses indicating that the challenging transition from standing to walking probably requires higher reliance on the visual input. The understanding of age-related differences in APAs may help to design training programs for the elderly specifically targeted to improve balance control in different sensory conditions, particularly during gait initiation.

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Intermuscular coherence reflects functional coordination

Journal of Neurophysiology ◽

10.1152/jn.00204.2017 ◽

2017 ◽

Vol 118 (3) ◽

pp. 1775-1783 ◽

Cited By ~ 21

Author(s):

Christopher M. Laine ◽

Francisco J. Valero-Cuevas

Keyword(s):

Spectral Properties ◽

Surface Emg ◽

Coherence Analysis ◽

Muscle Coordination ◽

Neural Drive ◽

Coordination Strategies ◽

Correlated Activity ◽

Neural Origin ◽

Intermuscular Coherence ◽

Neural Binding

Coherence analysis has the ability to identify the presence of common descending drive shared by motor unit pools and reveals its spectral properties. However, the link between spectral properties of shared neural drive and functional interactions among muscles remains unclear. We assessed shared neural drive between muscles of the thumb and index finger while participants executed two mechanically distinct precision pinch tasks, each requiring distinct functional coordination among muscles. We found that shared neural drive was systematically reduced or enhanced at specific frequencies of interest (~10 and ~40 Hz). While amplitude correlations between surface EMG signals also exhibited changes across tasks, only their coherence has strong physiological underpinnings indicative of neural binding. Our results support the use of intermuscular coherence as a tool to detect when coactivated muscles are members of a functional group or synergy of neural origin. Furthermore, our results demonstrate the advantages of considering neural binding at 10, ~20, and >30 Hz, as indicators of task-dependent neural coordination strategies. NEW & NOTEWORTHY It is often unclear whether correlated activity among muscles reflects their neural binding or simply reflects the constraints defining the task. Using the fact that high-frequency coherence between EMG signals (>6 Hz) is thought to reflect shared neural drive, we demonstrate that coherence analysis can reveal the neural origin of distinct muscle coordination patterns required by different tasks.

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Intermuscular coherence between homologous muscles during dynamic and static movement periods of bipedal squatting

Journal of Neurophysiology ◽

10.1152/jn.00231.2020 ◽

2020 ◽

Vol 124 (4) ◽

pp. 1045-1055

Author(s):

Rouven Kenville ◽

Tom Maudrich ◽

Carmen Vidaurre ◽

Dennis Maudrich ◽

Arno Villringer ◽

...

Keyword(s):

Body Movement ◽

Whole Body ◽

Coherence Analysis ◽

Lower Body ◽

Neural Drive ◽

Intermuscular Coherence ◽

The Central Nervous System ◽

Gamma Frequencies ◽

Alpha Beta ◽

Whole Body Movement

It is largely unexplored how the central nervous system achieves coordination of homologous muscles of the upper and lower body within a compound whole body movement, and to what extent this neural drive is modulated between different movement periods and muscles. Using intermuscular coherence analysis, we show that homologous muscle functions are mediated through common oscillatory input that extends over alpha, beta, and gamma frequencies with different synchronization patterns at different movement periods.

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Muscle Synergies in Patients With Multiple Sclerosis Reveal Demand-Specific Alterations in the Modular Organization of Locomotion

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2020.593365 ◽

2021 ◽

Vol 14 ◽

Author(s):

Lars Janshen ◽

Alessandro Santuz ◽

Adamantios Arampatzis

Keyword(s):

Multiple Sclerosis ◽

Motor Control ◽

Motor Task ◽

Time Dependent ◽

Motor Deficits ◽

Modular Organization ◽

Muscle Synergies ◽

Motor Primitives ◽

Leg Muscles ◽

Gait Parameters

For patients with multiple sclerosis (MS), deficits in gait significantly reduce the quality of life. Using the concept of muscle synergies, this study investigated the modular organization of motor control during level and inclined walking in MS patients (MSP) compared with healthy participants (HP) to identify the potential demand-specific adjustments in motor control in MSP. We hypothesized a widening of the time-dependent activation patterns (motor primitives) in MSP to increase the overlap of temporally-adjacent muscle synergies, especially during inclined walking, as a strategy to increase the robustness of motor control, thus compensating pathology-related deficits. We analyzed temporal gait parameters and muscle synergies from myoelectric signals of 13 ipsilateral leg muscles using non-negative matrix factorization. Compared with HP, MSP demonstrated a widening in the time-dependent coefficients (motor primitives), as well as altered relative muscle contribution (motor modules), in certain synergies during level and inclined walking. Moreover, inclined walking revealed a demand-specific adjustment in the modular organization in MSP, resulting in an extra synergy compared with HP. This further increased the overlap of temporally-adjacent muscle synergies to provide sufficient robustness in motor control to accomplish the more demanding motor task while coping with pathology-related motor deficits during walking.

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