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.

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.

Torso and Hip Muscle Activity and Resulting Spine Load and Stability while Using the ProFitter 3-D Cross Trainer

2009 ◽  
Vol 25 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Priyanka Banerjee ◽  
Stephen H.M Brown ◽  
Samuel J. Howarth ◽  
Stuart M. McGill
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Clinical Decision Making ◽  
Dynamic Balance ◽  
Gluteus Medius ◽  
Clinical Decision ◽  
Whole Body ◽  
Motor Patterns ◽  
Hip Muscle ◽  
Spine Mechanics

The ProFitter 3-D Cross Trainer is a labile surface device used in the clinic and claimed to train spine stability. The purpose of this study was to quantify the spine mechanics (compression and shear forces and stability), together with muscle activation mechanics (surface electromyography) of the torso and hip, during three ProFitter exercises. Trunk muscle activity was relatively low while exercising on the device (<25%MVC). Gluteus medius activity was phasic with the horizontal sliding position, especially for an experienced participant. Sufficient spinal stability was achieved in all three exercise conditions. Peak spinal compression values were below 3400 N (maximum 3188 N) and peak shear values were correspondingly low (under 500 N). The exercises challenge whole-body dynamic balance while producing very conservative spine loads. The motion simultaneously integrates hip and torso muscles in a way that appears to ensure stabilizing motor patterns in the spine. This information will assist with clinical decision making about the utility of the device and exercise technique in rehabilitation and training programs.

scholarly journals Consequences of biomechanically constrained tasks in the design and interpretation of synergy analyses

2015 ◽  
Vol 113 (7) ◽  
pp. 2102-2113 ◽  
Author(s):  
Katherine M. Steele ◽  
Matthew C. Tresch ◽  
Eric J. Perreault
Keyword(s):  
Matrix Factorization ◽  
Muscle Activity ◽  
Neural Control ◽  
Muscle Activation ◽  
Neuromuscular Control ◽  
Task Constraints ◽  
Factorization Algorithms ◽  
Low Dimensional ◽  
Or Task ◽  
And Task

Matrix factorization algorithms are commonly used to analyze muscle activity and provide insight into neuromuscular control. These algorithms identify low-dimensional subspaces, commonly referred to as synergies, which can describe variation in muscle activity during a task. Synergies are often interpreted as reflecting underlying neural control; however, it is unclear how these analyses are influenced by biomechanical and task constraints, which can also lead to low-dimensional patterns of muscle activation. The aim of this study was to evaluate whether commonly used algorithms and experimental methods can accurately identify synergy-based control strategies. This was accomplished by evaluating synergies from five common matrix factorization algorithms using muscle activations calculated from 1) a biomechanically constrained task using a musculoskeletal model and 2) without task constraints using random synergy activations. Algorithm performance was assessed by calculating the similarity between estimated synergies and those imposed during the simulations; similarities ranged from 0 (random chance) to 1 (perfect similarity). Although some of the algorithms could accurately estimate specified synergies without biomechanical or task constraints (similarity >0.7), with these constraints the similarity of estimated synergies decreased significantly (0.3–0.4). The ability of these algorithms to accurately identify synergies was negatively impacted by correlation of synergy activations, which are increased when substantial biomechanical or task constraints are present. Increased variability in synergy activations, which can be captured using robust experimental paradigms that include natural variability in motor activation patterns, improved identification accuracy but did not completely overcome effects of biomechanical and task constraints. These results demonstrate that a biomechanically constrained task can reduce the accuracy of estimated synergies and highlight the importance of using experimental protocols with physiological variability to improve synergy analyses.

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 The primary motor cortex prospectively computes the spinal reflex

2020 ◽  
Author(s):  
Tatsuya Umeda ◽  
Tadashi Isa ◽  
Yukio Nishimura
Keyword(s):  
Motor Cortex ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Linear Models ◽  
Movement Control ◽  
Spinal Reflex ◽  
Afferent Activity ◽  
Precise Movement ◽  
Behaving Monkeys

AbstractThe spinal reflex transforms sensory signals to generate muscle activity. However, it is unknown how the motor cortex (MCx) takes the spinal reflex into account when performing voluntary limb movements. We simultaneously recorded the activity of the MCx, afferent neurons, and forelimb muscles in behaving monkeys. We decomposed muscle activity into subcomponents explained by the MCx or afferent activity using linear models. Long preceding activity in the MCx, which is responsible for subsequent afferent activity, had the same spatiotemporal contribution to muscle activity as afferent activity, indicating that the MCx drives muscle activity not only by direct descending activation but also by trans-afferent descending activation. Therefore, the MCx implements internal models that prospectively estimate muscle activation via the spinal reflex for precise movement control.

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.

scholarly journals Locomotor patterns in cerebellar ataxia

2014 ◽  
Vol 112 (11) ◽  
pp. 2810-2821 ◽  
Author(s):  
G. Martino ◽  
Y. P. Ivanenko ◽  
M. Serrao ◽  
A. Ranavolo ◽  
A. d'Avella ◽  
...  
Keyword(s):  
Cerebellar Ataxia ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Rating Scale ◽  
Reaction Force ◽  
Neuromuscular Control ◽  
Pattern Generation ◽  
Heel Strike ◽  
Emg Activity ◽  
Foot Loading

Several studies have demonstrated how cerebellar ataxia (CA) affects gait, resulting in deficits in multijoint coordination and stability. Nevertheless, how lesions of cerebellum influence the locomotor muscle pattern generation is still unclear. To better understand the effects of CA on locomotor output, here we investigated the idiosyncratic features of the spatiotemporal structure of leg muscle activity and impairments in the biomechanics of CA gait. To this end, we recorded the electromyographic (EMG) activity of 12 unilateral lower limb muscles and analyzed kinematic and kinetic parameters of 19 ataxic patients and 20 age-matched healthy subjects during overground walking. Neuromuscular control of gait in CA was characterized by a considerable widening of EMG bursts and significant temporal shifts in the center of activity due to overall enhanced muscle activation between late swing and mid-stance. Patients also demonstrated significant changes in the intersegmental coordination, an abnormal transient in the vertical ground reaction force and instability of limb loading at heel strike. The observed abnormalities in EMG patterns and foot loading correlated with the severity of pathology [International Cooperative Ataxia Rating Scale (ICARS), a clinical ataxia scale] and the changes in the biomechanical output. The findings provide new insights into the physiological role of cerebellum in optimizing the duration of muscle activity bursts and the control of appropriate foot loading during locomotion.

Effects of intrathecal baclofen on voluntary motor control in spastic paresis

1990 ◽  
Vol 72 (3) ◽  
pp. 388-392 ◽  
Author(s):  
Mark L. Latash ◽  
Richard D. Penn ◽  
Daniel M. Corcos ◽  
Gerald L. Gottlieb
Keyword(s):  
Motor Control ◽  
Muscle Activation ◽  
Control Function ◽  
Muscle Tone ◽  
Intrathecal Baclofen ◽  
Intrathecal Administration ◽  
Motor Patterns ◽  
Content Type ◽  
Voluntary Muscle ◽  
Spastic Paresis

✓ Intrathecal baclofen injections were given to six patients with long-standing spastic paresis resistant to any nondestructive treatment, including oral baclofen. Attempts by the patients at voluntary muscle activation before intrathecal administration of baclofen led to considerable uncontrolled coactivation of antagonist and distant muscles. After the injection, dramatic suppression of the spastic signs was accompanied by more selective voluntary muscle activation. Tonic coactivation of the antagonists and distant muscle groups during voluntary contractions was decreased while the agonist level on electromyography (EMG) was not affected (three cases) or only slightly reduced (three cases). Furthermore, in one patient with sufficient residual motor control function, there was a considerable increase in the speed of fast isotonic movements, accompanied by the emergence of the ability to generate phasic muscle bursts on EMG that were characteristic of normal motor patterns. The results suggest that baclofen exerts different effects upon reflex pathways and descending motor pathways. This therapy appears to be a promising way for improving residual motor control in patients with increased muscle tone and/or reflexes.

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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