Effects of Gravity on Velopharyngeal Muscle Activity during Speech

1995 ◽  
Vol 32 (5) ◽  
pp. 371-375 ◽  
Author(s):  
Jerald B. Moon ◽  
John W. Canady
Keyword(s):  
Motor Control ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Body Position ◽  
Significant Group ◽  
Body Postures ◽  
Levator Veli Palatini ◽  
Gravity Effects ◽  
Velopharyngeal Function

Assessment of the role of gravitational forces in the motor control of the velopharyngeal mechanism was the focus of this study. Specifically, the effect of gravity on activation levels of the levator veli palatini and palatoglossus muscles was assessed. Nineteen volunteers repeated a CV syllable in upright and supine body positions. Overall, lower peak activation levels of levator veli palatini were observed in the supine body position. The results suggest that less muscle activity was seen in the levator veli palatini in the supine body posture, where gravitational effects worked in the same direction (i.e., toward closure). No statistically significant group effects were seen in muscle activation levels of palatoglossus across the two body postures, although clear gravity effects were observed in some subjects. The implications of these findings from a speech motor control perspective are discussed in relation to normal and disordered velopharyngeal function.

Effect of gravity and kinematic constraints on muscle synergies in arm cycling.

2021 ◽  
Author(s):  
Lilla Botzheim ◽  
Jozsef Laczko ◽  
Diego Torricelli ◽  
Mariann Mravcsik ◽  
José L. Pons ◽  
...  
Keyword(s):  
Motor Control ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Body Position ◽  
Medical Rehabilitation ◽  
Muscle Synergies ◽  
Muscle Coordination ◽  
Arm Cycling ◽  
Custom Made ◽  
Crank Length

Arm cycling is a bi-manual motor task used in medical rehabilitation and in sports training. Understanding how muscle coordination changes across different biomechanical constraints in arm cycling is a step towards improved rehabilitation approaches. This exploratory study aims to get new insights on motor control during arm cycling. To achieve our main goal, we used the muscle synergies analysis to test three hypotheses: 1) body position with respect to gravity (sitting and supine) has an effect on muscle synergies; 2) the movement size (crank length) has an effect on the synergistic behavior; 3) the bimanual cranking mode (asynchronous and synchronous) requires different synergistic control. Thirteen able-bodied volunteers performed arm cranking on a custom-made device with unconnected cranks, which allowed testing three different conditions: body position (sitting versus supine), crank length (10cm versus 15cm) and cranking mode (synchronous versus asynchronous). For each of the eight possible combinations, subjects cycled for 30 seconds while electromyography of 8 muscles (4 from each arm) were recorded: biceps brachii, triceps brachii, anterior deltoid and posterior deltoid. Muscle synergies in this 8-dimensional muscle space were extracted by non-negative matrix factorization. Four synergies accounted for over 90% of muscle activation variances in all conditions. Results showed that synergies were affected by body position and cranking mode but practically unaffected by movement size. These results suggest that the central nervous system may employ different motor control strategies in response to external constraints such as cranking mode and body position during arm cycling.

Tonic-to-phasic shift of lumbo-pelvic muscle activity during 8 weeks of bed rest and 6-months follow up

2007 ◽  
Vol 103 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Daniel L. Belavý ◽  
Carolyn A. Richardson ◽  
Stephen J. Wilson ◽  
Dieter Felsenberg ◽  
Jörn Rittweger
Keyword(s):  
Motor Control ◽  
Skill Acquisition ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Weight Bearing ◽  
Young Male ◽  
Bed Rest ◽  
Movement Model ◽  
Musculoskeletal Function

Prior motor control studies in unloading have shown a tonic-to-phasic shift in muscle activation, particularly in the short extensors. Tonic muscle activity is considered critical for normal musculoskeletal function. The shift from tonic-to-phasic muscle activity has not been systematically studied in humans in unloading nor at the lumbo-pelvic (LP) region. Ten healthy young male subjects underwent 8 wk of bed rest with 6-mo follow up as part of the “Berlin Bed-Rest Study.” A repetitive knee movement model performed in the prone position is used to stimulate tonic holding LP muscle activity, as measured by superficial EMG. Tonic and phasic activation patterns were quantified by relative height of burst vs. baseline electromyographic linear-envelope signal components. Statistical analysis shows a shift toward greater phasic activity during bed rest and follow up ( P < 0.001) with a significant interaction across muscles ( P < 0.001) specifically affecting the short lumbar extensors. These changes appear unrelated to skill acquisition over time ( P all ≥0.196). This change of a shift from tonic LP muscle activation to phasic is in line with prior research on the effects of reduced weight bearing on motor control.

scholarly journals Lower-limb muscle function is influenced by changing mechanical demands in cycling

2020 ◽  
pp. jeb.228221
Author(s):  
Adrian K. M. Lai ◽  
Taylor J. M. Dick ◽  
Nicholas A. T. Brown ◽  
Andrew A. Biewener ◽  
James M. Wakeling
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Muscle Function ◽  
Muscle Activation ◽  
Functional Index ◽  
Lower Limb Muscles ◽  
Wide Range ◽  
Musculoskeletal Simulations ◽  
Contractile Performance

Although cycling is often considered a seemingly simple, reciprocal task, muscles must adapt their function to satisfy changes in mechanical demands induced by higher crank torques and faster pedalling cadences. We examined if muscle function was sensitive to these changes in mechanical demands across a wide range of pedalling conditions. We collected experimental data of cycling where crank torque and pedalling cadence were independently varied from 13-44 Nm and 60-140 RPM. These data were used in conjunction with musculoskeletal simulations and a recently developed functional index-based approach to characterise the role of the human lower-limb muscles. We found that in muscles that generate most of the mechanical power and work during cycling, greater crank torque induced shifts towards greater muscle activation, greater positive muscle-tendon unit (MTU) work and a more motor-like function, particularly in the limb extensors. Conversely, with faster pedalling cadence, the same muscles exhibited a phase advance in muscle activity prior to crank top dead centre, which led to greater negative MTU power and work and shifted the muscles to contract with more spring-like behaviour. Our results illustrate the capacity for muscles to adapt their function to satisfy the mechanical demands of the task, even during highly constrained reciprocal tasks such as cycling. Understanding how muscles shift their contractile performance under varied mechanical and environmental demands may inform decisions on how to optimise pedalling performance and to design targeted cycling rehabilitation therapies for muscle-specific injuries or deficits.

scholarly journals EFFECTS OF CORE STABILIZATION EXERCISE ON MUSCLE ACTIVITY DURING HORIZONTAL SHOULDER ADDUCTION WITH LOADS IN HEALTHY ADULTS: A RANDOMIZED CONTROLLED STUDY

2021 ◽  
pp. 2140049
Author(s):  
CHANHEE PARK ◽  
SAMWON YOON ◽  
HYUNSIK YOON ◽  
KYOUNGTAE KIM ◽  
YOUNGJOO CHA ◽  
...  
Keyword(s):  
Motor Control ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Healthy Adults ◽  
Controlled Study ◽  
Maximal Voluntary Isometric Contraction ◽  
Spinal Stabilization ◽  
Stabilization Exercise ◽  
Core Stabilization ◽  
Upper Trapezius

The importance of core stabilization exercises for extremities associated with dynamic spinal stabilization prior to movement has been demonstrated. However, no previous studies have investigated the muscle-coordinated effects on the upper trapezius (UT), anterior deltoid (AD), pectoralis major (PM), bilateral transverse abdominis (TrA), bilateral internal oblique (IO), and bilateral external oblique (EO) in healthy adults. The purpose of this study was to compare the effects of the dynamic neuromuscular stabilization (DNS) breathing technique and the abdominal bracing (AB) technique on UT, AD, PM, bilateral IO/TrA, and bilateral EO motor control in healthy participants during horizontal shoulder adduction. Thirty-six participants, eight of whom were female, were randomized into an AB and a DNS group and performed horizontal shoulder adduction with loads (8 and 17 lb). The clinical outcomes were UT, AD, and PM muscle activation and TrA/IO and EO muscle activation. Paired t-tests were used to analyze electromyography (EMG) data to determine statistically significant differences in muscle activity between the two techniques. For the EMG analysis, the maximal voluntary isometric contraction was measured for normalization and then divided by the EMG amplitude value. The results showed that UT, AD, and PM muscle amplitudes were lower and TrA/IO and EO muscle amplitudes were higher with DNS than with AB ([Formula: see text]). Our findings provide clinical evidence that core exercise with DNS is more effective in lessening UT, AD, and PM muscle activation and improving bilateral TrA/IO motor control than with AB.

scholarly journals Cortical control of locomotor muscle activity through muscle synergies in humans: a neural decoding study

2018 ◽  
Author(s):  
Hikaru Yokoyama ◽  
Naotsugu Kaneko ◽  
Tetsuya Ogawa ◽  
Noritaka Kawashima ◽  
Katsumi Watanabe ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Indirect Evidence ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Neural Decoding ◽  
Individual Muscle ◽  
Cortical Involvement ◽  
Decoding Accuracy

AbstractWalking movements are orchestrated by the activation of a large number of muscles. The control of numerous muscles during walking is believed to be simplified by flexible activation of groups of muscles called muscle synergies. Although significant corticomuscular connectivity during walking has been reported, the level at which the cortex controls locomotor muscle activity (i.e., muscle synergy or individual muscle level) remains unclear. Here, we examined cortical involvement in muscle control during walking by brain decoding of the activation of muscle synergies and individual muscles from electroencephalographic (EEG) signals using linear decoder models. First, we demonstrated that activation of locomotor muscle synergies was decoded from slow cortical waves with significant accuracy. In addition, we found that decoding accuracy for muscle synergy activation was greater than that for individual muscle activation and that decoding of individual muscle activation was based on muscle synergy-related cortical information. Taken together, these results provide indirect evidence that the cerebral cortex hierarchically controls multiple muscles through a few muscle synergies during walking. Our findings extend the current understanding of the role of the cortex in muscular control during walking and could accelerate the development of effective brain-machine interfaces for people with locomotor disabilities.

Function of the Thyroarytenoid Muscle in a Canine Laryngeal Model

1993 ◽  
Vol 102 (10) ◽  
pp. 769-776 ◽  
Author(s):  
Hong-Shik Choi ◽  
Ming Ye ◽  
Gerald S. Berke ◽  
Jody Kreiman
Keyword(s):  
Muscle Activity ◽  
High Frequency ◽  
Vocal Fold ◽  
Muscle Activation ◽  
Thyroid Cartilage ◽  
Vocal Folds ◽  
Vocal Fold Vibration ◽  
Thyroarytenoid Muscle

Fundamental frequency is controlled by contraction of the thyroarytenoid (TA) and cricothyroid (CT) muscles. While activity of the CT muscle is known to tense and thin the vocal folds, little is known about the effect of the TA muscle on vocal fold vibration. An in vivo canine laryngeal model was used to examine the role of the TA muscle in controlling phonation. Isolated TA muscle activation was obtained by stimulating sectioned terminal TA branches through small thyroid cartilage windows. Subglottic pressure measures, electroglottographic and photoglottographic signals, and acoustic signals were obtained in 5 mongrel dogs during dynamic and static variations in TA muscle activity. Results indicated that TA muscle activation is a major determinant in sudden shifts from high-frequency to modal phonation. Subglottic pressure increased and open quotient decreased gradually with increasing TA activation.

Effect of Temporary Closure of Oronasal Fistulae on Levator Veli Palatini Muscle Activity

1997 ◽  
Vol 34 (6) ◽  
pp. 505-511 ◽  
Author(s):  
Takashi Tachimura ◽  
Hisanaga Hara ◽  
Hideyasu Koh ◽  
Takeshi Wada
Keyword(s):  
Muscle Activity ◽  
Hard Palate ◽  
Air Pressure ◽  
Electromyographic Activity ◽  
Cotton Swab ◽  
Levator Veli Palatini ◽  
Oronasal Fistula ◽  
Velopharyngeal Incompetence ◽  
Velopharyngeal Function ◽  
Temporary Closure

Objective: The objective of this study was to clarify electromyographically the effects of closing an oronasal fistula on levator muscle activity and oral air pressure in patients with velopharyngeal incompetence and in those with adequate velopharyngeal function. Subjects: Five patients with adequate velopharyngeal function and six patients with velopharyngeal incompetence were studied. All subjects had an oronasal fistula at the anterior third portion of the hard palate in spite of primary palatal closure using palatal push-back operation. Outcome Measures: The smoothed electromyographic activity of the levator veli palatini muscle was measured with the fistula closed with a cotton swab dipped in saline and with the fistula left open. Results: Under the closed fistula condition, oral air pressure was greater than that observed under the open fistula condition irrespective of velopharyngeal function. Levator veli palatini muscle activity was significantly lower in magnitude under the condition of closure than under the open condition in the patients with adequate velopharyngeal function, whereas in those with velopharyngeal incompetence, it was not significantly changed. Conclusions: The results suggest that velopharyngeal function is affected by temporary closure of an oronasal fistula, and that the magnitude of the effect is greater for subjects with adequate velopharyngeal function than for subjects with velopharyngeal incompetence.

Reestablishing Proprioception and Neuromuscular Control in the ACL-Injured Athlete

1997 ◽  
Vol 6 (2) ◽  
pp. 182-206 ◽  
Author(s):  
C. Buz Swanik ◽  
Scott M. Lephart ◽  
Frank P. Giannantonio ◽  
Freddie H. Fu
Keyword(s):  
Motor Control ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Neuromuscular Control ◽  
Muscle Stiffness ◽  
Spinal Reflexes ◽  
Spinal Reflex ◽  
Functional Stability ◽  
Motor Patterns ◽  
Feed Forward

Anterior cruciate ligament (ACL) injury disrupts static and dynamic knee restraints, compromising functional stability. Deafferentation of ACL mechan-oreceptors alters the spinal reflex pathways to motor nerves and muscle spindles in addition to the cortical pathways for conscious and unconscious appreciation of proprioception and kinesthesia. These pathways are required by the feed-forward and feedback neuromuscular control systems to dynamically stabilize joints. Feed-forward motor control is responsible for preparatory muscle activity, while feedback motor control regulates reactive muscle activity. The level of muscle activation, preparatory or reactive, influences muscular stiffness, thereby providing dynamic restraint for the ACL-deficient athlete. Rehabilitation protocols should incorporate activities that enhance muscle stiffness while encouraging adaptations to peripheral afferents, spinal reflexes, and cortical motor patterns. Four elements crucial for reestablishing neuromuscular control and functional stability are proprioceptive and kinesthetic awareness, dynamic stability, preparatory and reactive muscle characteristics, and conscious and unconscious functional motor patterns.

scholarly journals A Systematic Review of EMG Applications for the Characterization of Forearm and Hand Muscle Activity during Activities of Daily Living: Results, Challenges, and Open Issues

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3035
Author(s):  
Néstor J. Jarque-Bou ◽  
Joaquín L. Sancho-Bru ◽  
Margarita Vergara
Keyword(s):  
Activities Of Daily Living ◽  
Musculoskeletal System ◽  
Muscle Activity ◽  
Daily Living ◽  
Muscle Activation ◽  
Human Hand ◽  
Hand Motion ◽  
Biomechanical Models ◽  
Rehabilitation Protocols ◽  
Open Issues

The role of the hand is crucial for the performance of activities of daily living, thereby ensuring a full and autonomous life. Its motion is controlled by a complex musculoskeletal system of approximately 38 muscles. Therefore, measuring and interpreting the muscle activation signals that drive hand motion is of great importance in many scientific domains, such as neuroscience, rehabilitation, physiotherapy, robotics, prosthetics, and biomechanics. Electromyography (EMG) can be used to carry out the neuromuscular characterization, but it is cumbersome because of the complexity of the musculoskeletal system of the forearm and hand. This paper reviews the main studies in which EMG has been applied to characterize the muscle activity of the forearm and hand during activities of daily living, with special attention to muscle synergies, which are thought to be used by the nervous system to simplify the control of the numerous muscles by actuating them in task-relevant subgroups. The state of the art of the current results are presented, which may help to guide and foster progress in many scientific domains. Furthermore, the most important challenges and open issues are identified in order to achieve a better understanding of human hand behavior, improve rehabilitation protocols, more intuitive control of prostheses, and more realistic biomechanical models.

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