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  1. Article ; Online: The effect of inherent and incidental constraints on bimanual force control in simulated Martian gravity.

    Wang, Yiyu / Neto, Osmar P / Weinrich, Madison / Abbott, Renee / Diaz-Artiles, Ana / Kennedy, Deanna M

    Human movement science

    2024  Volume 95, Page(s) 103199

    Abstract: The ability to coordinate actions between the limbs is important for many operationally relevant tasks associated with space exploration. A future milestone in space exploration is sending humans to Mars. Therefore, an experiment was designed to examine ... ...

    Abstract The ability to coordinate actions between the limbs is important for many operationally relevant tasks associated with space exploration. A future milestone in space exploration is sending humans to Mars. Therefore, an experiment was designed to examine the influence of inherent and incidental constraints on the stability characteristics associated with the bimanual control of force in simulated Martian gravity. A head-up tilt (HUT)/head-down tilt (HDT) paradigm was used to simulate gravity on Mars (22.3° HUT). Right limb dominant participants (N = 11) were required to rhythmically coordinate patterns of isometric forces in 1:1 in-phase and 1:2 multifrequency patterns by exerting force with their right and left limbs. Lissajous displays were provided to guide task performance. Participants performed 14 twenty-second practice trials at 90° HUT (Earth). Following a 30-min rest period, participants performed 2 test trials for each coordination pattern in both Earth and Mars conditions. Performance during the test trials were compared. Results indicated very effective temporal performance of the goal coordination tasks in both gravity conditions. However, results indicated differences associated with the production of force between Earth and Mars. In general, participants produced less force in simulated Martian gravity than in the Earth condition. In addition, force production was more harmonic in Martian gravity than Earth gravity for both limbs, indicating that less force distortions (adjustments, hesitations, and/or perturbations) occurred in the Mars condition than in the Earth condition. The force coherence analysis indicated significantly higher coherence in the 1:1 task than in the 1:2 task for all force frequency bands, with the highest level of coherence in the 1-4 Hz frequency band for both gravity conditions. High coherence in the 1-4 Hz frequency band is associated with a common neural drive that activates the two arms simultaneously and is consistent with the requirements of the two tasks. The results also support the notion that neural crosstalk stabilizes the performance of the 1:1 in-phase task. In addition, significantly higher coherence in the 8-12 Hz frequency bands were observed for the Earth condition than the Mars condition. Force coherence in the 8-12 Hz bands is associated with the processing of sensorimotor information, suggesting that participants were better at integrating visual, proprioceptive, and/or tactile feedback in Earth than for the Mars condition. Overall, the results indicate less neural interference in Martian gravity; however, participants appear to be more effective at using the Lissajous displays to guide performance under Earth's gravity.
    Language English
    Publishing date 2024-03-20
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 601851-8
    ISSN 1872-7646 ; 0167-9457
    ISSN (online) 1872-7646
    ISSN 0167-9457
    DOI 10.1016/j.humov.2024.103199
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Increased voluntary drive is associated with changes in common oscillations from 13 to 60 Hz of interference but not rectified electromyography.

    Neto, Osmar P / Baweja, Harsimran S / Christou, Evangelos A

    Muscle & nerve

    2010  Volume 42, Issue 3, Page(s) 348–354

    Abstract: The purpose of this study was to compare the capability of interference and rectified electromyography (EMG) to detect changes in the beta (13-30-HZ) and Piper (30-60-HZ) bands when voluntary force is increased. Twenty adults exerted a constant force ... ...

    Abstract The purpose of this study was to compare the capability of interference and rectified electromyography (EMG) to detect changes in the beta (13-30-HZ) and Piper (30-60-HZ) bands when voluntary force is increased. Twenty adults exerted a constant force abduction of the index finger at 15% and 50% of maximum. The common oscillations at various frequency bands (0-500 HZ) were estimated from the first dorsal interosseous muscle using cross wavelets of interference and rectified EMG. For the interference EMG signals, normalized power significantly (P < 0.01) increased with force in the beta (9.0 +/- 0.9 vs. 15.5 +/- 2.1%) and Piper (13.6 +/- 0.9 vs. 21 +/- 1.7%) bands. For rectified EMG signals, however, the beta and Piper bands remained unchanged (P > 0.4). Although rectified EMG is used in many clinical studies to identify changes in the oscillatory drive to the muscle, our findings suggest that only interference EMG can accurately capture the increase in oscillatory drive from 13 to 60 HZ with voluntary force.
    MeSH term(s) Adult ; Algorithms ; Drive ; Electroencephalography ; Electromyography/standards ; Female ; Fingers/innervation ; Fingers/physiology ; Humans ; Isometric Contraction/physiology ; Magnetoencephalography ; Male ; Motor Cortex/physiology ; Motor Neurons/physiology ; Muscle, Skeletal/innervation ; Muscle, Skeletal/physiology ; Young Adult
    Language English
    Publishing date 2010-06-30
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 438353-9
    ISSN 1097-4598 ; 0148-639X
    ISSN (online) 1097-4598
    ISSN 0148-639X
    DOI 10.1002/mus.21687
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: The interaction of respiration and visual feedback on the control of force and neural activation of the agonist muscle.

    Baweja, Harsimran S / Patel, Bhavini K / Neto, Osmar P / Christou, Evangelos A

    Human movement science

    2011  Volume 30, Issue 6, Page(s) 1022–1038

    Abstract: The purpose of this study was to compare force variability and the neural activation of the agonist muscle during constant isometric contractions at different force levels when the amplitude of respiration and visual feedback were varied. Twenty young ... ...

    Abstract The purpose of this study was to compare force variability and the neural activation of the agonist muscle during constant isometric contractions at different force levels when the amplitude of respiration and visual feedback were varied. Twenty young adults (20-32 years, 10 men and 10 women) were instructed to accurately match a target force at 15% and 50% of their maximal voluntary contraction (MVC) with abduction of the index finger while controlling their respiration at different amplitudes (85%, 100% and 125% normal) in the presence and absence of visual feedback. Each trial lasted 22s and visual feedback was removed from 8-12 and 16-20s. Each subject performed three trials with each respiratory condition at each force level. Force variability was quantified as the standard deviation of the detrended force data. The neural activation of the first dorsal interosseus (FDI) was measured with bipolar surface electrodes placed distal to the innervation zone. Relative to normal respiration, force variability increased significantly only during high-amplitude respiration (∼63%). The increase in force variability from normal- to high-amplitude respiration was strongly associated with amplified force oscillations from 0 to 3 Hz (R(2) ranged from .68 to .84, p< .001). Furthermore, the increase in force variability was exacerbated in the presence of visual feedback at 50% MVC (vision vs. no-vision: .97 vs. .87N) and was strongly associated with amplified force oscillations from 0 to 1 Hz (R(2)= .82) and weakly associated with greater power from 12 to 30 Hz (R(2)= .24) in the EMG of the agonist muscle. Our findings demonstrate that high-amplitude respiration and visual feedback of force interact and amplify force variability in young adults during moderate levels of effort.
    MeSH term(s) Adult ; Analysis of Variance ; Electromyography ; Feedback, Sensory/physiology ; Female ; Fingers/innervation ; Humans ; Isometric Contraction/physiology ; Male ; Muscle Fatigue/physiology ; Muscle, Skeletal/innervation ; Peripheral Nerves/physiology ; Pulmonary Ventilation/physiology ; Signal Processing, Computer-Assisted ; Transducers, Pressure ; Young Adult
    Language English
    Publishing date 2011-05-04
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 601851-8
    ISSN 1872-7646 ; 0167-9457
    ISSN (online) 1872-7646
    ISSN 0167-9457
    DOI 10.1016/j.humov.2010.09.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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