scholarly journals Independent control of cocontraction and reciprocal activity during goal-directed reaching in muscle space

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Atsushi Takagi ◽  
Hiroyuki Kambara ◽  
Yasuharu Koike
Keyword(s):  
Muscle Force ◽  
Joint Torque ◽  
Vertical Position ◽  
Shoulder Flexion ◽  
Control Framework ◽  
Flexion Extension ◽  
Maximal Activation ◽  
Muscle Pair ◽  
The Central Nervous System ◽  
The Difference

AbstractThe movement in a joint is facilitated by a pair of muscles that pull in opposite directions. The difference in the pair’s muscle force or reciprocal activity results in joint torque, while the overlapping muscle force or the cocontraction is related to the joint’s stiffness. Cocontraction knowingly adapts implicitly over a number of movements, but it is unclear whether the central nervous system can actively regulate cocontraction in a goal-directed manner in a short span of time. We developed a muscle interface where a cursor’s horizontal position was determined by the reciprocal activity of the shoulder flexion–extension muscle pair, while the vertical position was controlled by its cocontraction. Participants made goal-directed movements to single and via-point targets in the two-dimensional muscle space, learning to move the cursor along the shortest path. Simulations using an optimal control framework suggest that the reciprocal activity and the cocontraction may be controlled independently by the CNS, albeit at a rate orders of magnitude slower than the muscle’s maximal activation speed.

ESTIMATING MUSCLE FORCES AND KNEE JOINT TORQUE USING SURFACE ELECTROMYOGRAPHY: A MUSCULOSKELETAL BIOMECHANICAL MODEL

2017 ◽  
Vol 17 (04) ◽  
pp. 1750069 ◽  
Author(s):  
JIANGCHENG CHEN ◽  
XIAODONG ZHANG ◽  
LINXIA GU ◽  
CARL NELSON
Keyword(s):  
Knee Joint ◽  
Surface Electromyography ◽  
Neural Control ◽  
Muscle Activation ◽  
Muscle Force ◽  
Dynamic Properties ◽  
Biomechanical Model ◽  
Joint Torque ◽  
Muscle Forces ◽  
Flexion Extension

Surface electromyography (sEMG) is a useful tool for revealing the underlying musculoskeletal dynamic properties in the human body movement. In this paper, a musculoskeletal biomechanical model which relates the sEMG and knee joint torque is proposed. First, the dynamic model relating sEMG to skeletal muscle activation considering frequency and amplitude is built. Second, a muscle contraction model based on sliding-filament theory is developed to reflect the physiological structure and micro mechanical properties of the muscle. The muscle force and displacement vectors are determined and the transformation from muscle force to knee joint moment is realized, and finally a genetic algorithm-based calibration method for the Newton–Euler dynamics and overall musculoskeletal biomechanical model is put forward. Following the model calibration, the flexion/extension (FE) knee joint torque of eight subjects under different walking speeds was predicted. Results show that the forward biomechanical model can capture the general shape and timing of the joint torque, with normalized mean residual error (NMRE) of [Formula: see text]10.01%, normalized root mean square error (NRMSE) of [Formula: see text]12.39% and cross-correlation coefficient of [Formula: see text]0.926. The musculoskeletal biomechanical model proposed and validated in this work could facilitate the study of neural control and how muscle forces generate and contribute to the knee joint torque during human movement.

scholarly journals Development and Evaluation of a Musculoskeletal Model of the Elbow Joint Complex

1996 ◽  
Vol 118 (1) ◽  
pp. 32-40 ◽  
Author(s):  
R. V. Gonzalez ◽  
E. L. Hutchins ◽  
R. E. Barr ◽  
L. D. Abraham
Keyword(s):  
Elbow Joint ◽  
Muscle Force ◽  
Elbow Flexion ◽  
Musculoskeletal Model ◽  
Joint Torque ◽  
Time Varying ◽  
Moment Arm ◽  
Flexion Extension ◽  
The Relationship ◽  
Ballistic Movements

This paper describes the development and evaluation of a musculoskeletal model that represents human elbow flexion-extension and forearm pronation-supination. The length, velocity, and moment arm for each of the eight musculotendon actuators were based on skeletal anatomy and joint position. Musculotendon parameters were determined for each actuator and verified by comparing analytical moment-angle curves with experimental joint torque data. The parameters and skeletal geometry were also utilized in the musculoskeletal model for the analysis of ballistic (rapid-directed) elbow joint complex movements. The key objective was to develop a computational model, guided by parameterized optimal control, to investigate the relationship among patterns of muscle excitation, individual muscle forces, and to determine the effects of forearm and elbow position on the recruitment of individual muscles during a variety of ballistic movements. The model was partially verified using experimental kinematic, torque, and electromyographic data from volunteer subjects performing both isometric and ballistic elbow joint complex movements. This verification lends credibility to the time-varying muscle force predictions and the recruitment of muscles that contribute to both elbow flexion-extension and forearm pronation-supination.

Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

2021 ◽  
Vol 49 (4) ◽  
pp. 994-1004
Author(s):  
Andreas Martin Seitz ◽  
Florian Schall ◽  
Steffen Paul Hacker ◽  
Stefan van Drongelen ◽  
Sebastian Wolf ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Muscle Force ◽  
Meniscal Tear ◽  
In Vitro Tests ◽  
Jump Landing ◽  
Medial Meniscectomy ◽  
Attachment Structures ◽  
Flexion Extension ◽  
Longitudinal Tear

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% ( P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces ( P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced ( P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

Is intervertebral disc degeneration related to segmental instability? An evaluation with two different grading systems based on clinical imaging

2017 ◽  
Vol 59 (3) ◽  
pp. 327-335 ◽  
Author(s):  
David Volkheimer ◽  
Fabio Galbusera ◽  
Christian Liebsch ◽  
Sabine Schlegel ◽  
Friederike Rohlmann ◽  
...  
Keyword(s):  
Intervertebral Disc Degeneration ◽  
Statistical Significance ◽  
Axial Rotation ◽  
Spinal Motion ◽  
X Ray ◽  
Grading Systems ◽  
Flexion Extension ◽  
The Difference ◽  
Magnetic Resonance Imaging Mri

Background Several in vitro studies investigated how degeneration affects spinal motion. However, no consensus has emerged from these studies. Purpose To investigate how degeneration grading systems influence the kinematic output of spinal specimens. Material and Methods Flexibility testing was performed with ten human T12-S1 specimens. Degeneration was graded using two different classifications, one based on X-ray and the other one on magnetic resonance imaging (MRI). Intersegmental rotation (expressed by range of motion [ROM] and neutral zone [NZ]) was determined in all principal motion directions. Further, shear translation was measured during flexion/extension motion. Results The X-ray grading system yielded systematically lesser degeneration. In flexion/extension, only small differences in ROM and NZ were found between moderately degenerated motion segments, with only NZ for the MRI grading reaching statistical significance. In axial rotation, a significant increase in NZ for moderately degenerated segments was found for both grading systems, whereas the difference in ROM was significant only for the MRI scheme. Generally, the relative increases were more pronounced for the MRI classification compared to the X-ray grading scheme. In lateral bending, only relatively small differences between the degeneration groups were found. When evaluating shear translations, a non-significant increase was found for moderately degenerated segments. Motion segment segments tended to regain stability as degeneration progressed without reaching the level of statistical significance. Conclusion We found a fair agreement between the grading schemes which, nonetheless, yielded similar degeneration-related effects on intersegmental kinematics. However, as the trends were more pronounced using the Pfirrmann classification, this grading scheme appears superior for degeneration assessment.

PENGARUH BUERGER ALLEN EXERCISE TERHADAP NILAI ANKLE BRACHIAL INDEX PADA PASIEN DIABETES MELITUS

2021 ◽  
Vol 4 (1) ◽  
pp. 90-94
Author(s):  
Pratiwi Christa Simarmata ◽  
Sari Desi Esta Ulina Sitepu ◽  
Abdi Lestari Sitepu ◽  
Ruttama Hutauruk ◽  
Rita Ayu Butar-butar
Keyword(s):  
Diabetes Mellitus ◽  
Exercise Intervention ◽  
Ankle Brachial Index ◽  
Endocrine System ◽  
Sampling Technique ◽  
Wilcoxon Test ◽  
Flexion Extension ◽  
Patients With Diabetes ◽  
Quasi Experimental ◽  
The Difference

Diabetes mellitus is a disorder of the endocrine system characterized by increased levels of glucose in the blood. The purpose of this study was to assess the effect of Buerger's Allen exercise on the value of the ankle brachial index (ABI) in patients with diabetes mellitus. The research design was a quasi-experimental pretest and posttest without a control. The study was conducted from March to May 2021 at Grandmed Lubuk Pakam Hospital with 48 respondents, with consecutive sampling technique. Data were analyzed using the Wilcoxon test. The Buergers Allen exercise intervention was performed twice a day, for three weeks. The procedure is performed by lifting the lower extremities up at an angle of 45-90 degrees for 2-3 minutes, then the patient sits at the bedside with the legs hanging down, accompanied by flexion, extension, pronation and supination movements for 5-10 minutes, and the patient lies down. with both feet resting for 10 minutes. There was a significant effect between the mean ABI value before intervention 0.83 and after intervention 0.95, p=0.00. The difference in mean ABI p=0.000, p<0.05. The results of the study concluded that there was an effect of buerger allen exercise on the ABI value before and after the intervention where the ABI value was getting better. It is recommended for nurses to make Buergers Allen exercise one of the independent nursing interventions in providing nursing care to patients with diabetes mellitus.

Cholecystokinin octapeptide analogues suppress food intake via central CCK-A receptors in mice

1993 ◽  
Vol 265 (3) ◽  
pp. R481-R486 ◽  
Author(s):  
Y. Hirosue ◽  
A. Inui ◽  
A. Teranishi ◽  
M. Miura ◽  
M. Nakajima ◽  
...  
Keyword(s):  
Food Intake ◽  
Receptor Antagonist ◽  
Rank Order ◽  
Peripheral Circulation ◽  
Inhibitory Effect ◽  
Peripheral Tissues ◽  
Cholecystokinin Octapeptide ◽  
The Central Nervous System ◽  
The Difference ◽  
The Brain

To examine the mechanism of the satiety-producing effect of cholecystokinin (CCK) in the central nervous system, we compared the potency of intraperitoneally (ip) or intracerebroventricularly (icv) administered CCK-8 and its analogues on food intake in fasted mice. The icv administration of a small dose of CCK-8 (0.03 nmol/brain) or of Suc-(Thr28, Leu29, MePhe33)-CCK-7 (0.001 nmol/brain) suppressed food intake for 20 min, whereas CCK-8 (1 nmol/kg, which is equivalent to 0.03 nmol/brain) or Suc-(Thr28, Leu29, MePhe33)-CCK-7 (1 nmol/kg) had satiety effect after ip administration. Dose-response studies indicated the following rank order of potency: Suc-CCK-7 > or = Suc-(Thr28, Leu29, MePhe33)-CCK-7 > or = CCK-8 > or = (Nle28,31)-CCK-8 >> desulfated CCK-8 = CCK-4 = 0 in the case of ip administration and Suc-(Thr28, Leu29, MePhe33)-CCK-7 >> Suc-CCK-7 > or = CCK-8 > or = (Nle28,31)-CCK-8 >> desulfated CCK-8 = CCK-4 = 0 in the case of icv administration. The selective CCK-A receptor antagonist MK-329 reversed the inhibitory effect of the centrally as well as peripherally administered CCK-8, or of Suc-(Thr28, Leu29, MePhe33)-CCK-7, whereas the selective CCK-B receptor antagonist L-365260 did not. The icv administered CCK-8 did not appear in the peripheral circulation. These findings suggest the participation of CCK-A receptors in the brain in mediating the satiety effect of CCK and the difference in CCK-A receptors in the brain and peripheral tissues.

AN ALGORITHM TO CALCULATE THE COMPONENTS OF ALL MUSCLE FORCES DURING EACH PHASES OF THE GAIT CYCLE, FOR THE PELVIC-FEMUR COMPLEX

2005 ◽  
Vol 05 (04) ◽  
pp. 539-548 ◽  
Author(s):  
SANTANU MAJUMDER ◽  
AMIT ROYCHOWDHURY ◽  
SUBRATA PAL
Keyword(s):  
Finite Element ◽  
Hip Joint ◽  
Computational Models ◽  
Gait Cycle ◽  
Muscle Force ◽  
Fe Analysis ◽  
Muscle Forces ◽  
Force Magnitude ◽  
Flexion Extension ◽  
Force Components

With the help of finite element (FE) computational models of femur, pelvis or hip joint to perform quasi-static stress analysis during the entire gait cycle, muscle force components (X, Y, Z) acting on the hip joint and pelvis are to be known. Most of the investigators have presented only the net muscle force magnitude during gait. However, for the FE software, either muscle force components (X, Y, Z) or three angles for the muscle line of action are required as input. No published algorithm (with flowchart) is readily available to calculate the required muscle force components for FE analysis. As the femur rotates about the hip center during gait, the lines of action for 27 muscle forces are also variable. To find out the variable lines of action and muscle force components (X, Y, Z) with directions, an algorithm was developed and presented here with detailed flowchart. We considered the varying angles of adduction/abduction, flexion/extension during gait. This computer program, obtainable from the first author, is able to calculate the muscle force components (X, Y, Z) as output, if the net magnitude of muscle force, hip joint orientations during gait and muscle origin and insertion coordinates are provided as input.

scholarly journals MM-MRE: a new technique to quantify individual muscle forces during isometric tasks of the wrist using MR elastography

2019 ◽  
Author(s):  
Andrea Zonnino ◽  
Daniel R. Smith ◽  
Peyton L. Delgorio ◽  
Curtis L. Johnson ◽  
Fabrizio Sergi
Keyword(s):  
Shear Wave ◽  
Muscle Force ◽  
Muscle Mechanics ◽  
Neuromuscular Control ◽  
Joint Torque ◽  
New Technique ◽  
Muscle Forces ◽  
Individual Muscle ◽  
Complete Set ◽  
A New Technique

AbstractNon-invasive in-vivo measurement of individual muscle force is limited by the infeasibility of placing force sensing elements in series with the musculo-tendon structures. At the same time, estimating muscle forces using EMG measurements is prone to inaccuracies, as EMG is not always measurable for the complete set of muscles acting around the joints of interest. While new methods based on shear wave elastography have been recently proposed to directly characterize muscle mechanics, they can only be used to measure muscle forces in a limited set of superficial muscles. As such, they are not suitable to study the neuromuscular control of movements that require coordinated action of multiple muscles.In this work, we present multi-muscle magnetic resonance elastography (MM-MRE), a new technique capable of quantifying individual muscle force from the complete set of muscles in the forearm, thus enabling the study of the neuromuscular control of wrist movements. MM-MRE integrates measurements of joint torque provided by an MRI-compatible instrumented handle with muscle-specific measurements of shear wave speed obtained via MRE to quantify individual muscle force using model-based estimator.A single-subject pilot experiment demonstrates the possibility of obtaining measurements from individual muscles and establishes that MM-MRE has sufficient sensitivity to detect changes in muscle mechanics following the application of isometric joint torque with self-selected intensity.

scholarly journals QT Dispersion: A Predictor of Outcome Following Acute Neurologic Events

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 343-343
Author(s):  
Elzbieta J Wirkowski ◽  
Joseph Moonjely ◽  
Todd J Cohen ◽  
Stephanie M Manzella ◽  
Richard H Smith ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Functional Outcome ◽  
Qt Dispersion ◽  
Neurological Injury ◽  
Disease States ◽  
Qt Intervals ◽  
The Central Nervous System ◽  
The Difference ◽  
Adjusted Logistic Regression

P26 BACKGROUND: QT dispersion (QTD) reflects heterogeneity of myocardial repolarization, which is modulated by the central nervous system. Pervious studies have shown increased QTD to be a predictor of adverse outcome in various cardiac disease states. However, the central nervous system effects on QTD and its relation to functional outcomes have not been previously studied in patients with acute neurological events (NE). The objective of this study was to determine whether increased QTD is related to functional outcome in patients with cerebrovascular accidents (CVA) and transient ischemic attacks (TIA). METHODS: We studied 140 consecutive pts. aged 72±10 yrs. (48% male) admitted to our institution with NE from 1/98 to 4/98. QTD was calculated from admission EKG as the difference between maximum and minimum QT intervals. 120 pts. had interpretable EKGs with measurable QT intervals in at least 11 of 12 leads. Three separate functional scales (NIHSS, Barthel, and Rankin) were obtained on admission and discharge were recorded. RESULTS: QTD was higher in pts. with intracerebral hemorrhage as compared to CVA and TIA (70±15 vs. 53±27 vs. 48±31 msecs. p=0.03). Increased QTD was associated with lower functional outcome on all 3 scales (all p<0.05) and with higher mortality (p=0.02). QTD was higher in pts. with congestive heart failure (80±43 vs. 47±24 msecs. p=0.006) and carotid disease (59±32 vs. 46±27 msecs. p=0.045) as compared to those without. QTD was not associated with atrial fibrillation or coronary disease. All patients with TIA survived. On multivariate analysis, other independent predictors of poorer outcome were QTD (OR 1.35, 95% CI 1.08–1.68) and a trend towards age (OR 1.07, 95% CI 0.99–1.16). On age-adjusted logistic regression, mortality increased by an OR 1.28, 95% (CI 1.02–1.61) for every 10 msec increase in QTD. CONCLUSION: QTD is an independent predictor of functional outcome and mortality following acute neurological events. In this setting, QTD reflects acute neurological injury as well as underlying heart disease. The mechanism of these findings merits further study.

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