scholarly journals Mechanistic insights into the modulatory role of the mechanoreflex on central hemodynamics using passive leg movement in humans

2018 ◽  
Vol 125 (2) ◽  
pp. 545-552 ◽  
Author(s):  
Nicholas T. Kruse ◽  
William E. Hughes ◽  
Darren P. Casey
Keyword(s):  
Cardiac Output ◽  
Angular Velocity ◽  
Range Of Motion ◽  
Joint Angle ◽  
Feedback Mechanism ◽  
Fascicle Length ◽  
Percent Change ◽  
Muscle Fascicle ◽  
Angular Velocities ◽  
Leg Movement

The aim of this study was to examine the independent contributions of joint range of motion (ROM), muscle fascicle length (MFL), and joint angular velocity on mechanoreceptor-mediated central cardiovascular dynamics using passive leg movement (PLM) in humans. Twelve healthy men (age: 23 ± 2 yr, body mass index: 23.7 kg/m2) performed continuous PLM at various randomized joint angle ROMs (0°–50° vs. 50°–100° vs. 0°–100°) and joint angular velocities (“fast”: 200°/s vs. “slow”: 100°/s). Measures of heart rate (HR), cardiac output (CO), and mean arterial pressure (MAP) were recorded during baseline and during 60 s of PLM. MFL was calculated from muscle architectural measurements of fascicle pennation angle and tissue thickness (Doppler ultrasound). Percent change in MFL increased across the transition of PLM from 0° to 50° (15 ± 3%; P < 0.05) and from 0° to 100° knee flexion (27 ± 4%; P < 0.05). The average peak percent change in HR (increased, approx. +5 ± 2%; P < 0.05), CO (increased, approx. +5 ± 3%; P < 0.05), and MAP (decreased, approx. −2 ± 2%; P < 0.05) were similar between fast versus slow angular velocities when compared against shorter absolute joint ROMs (i.e., 0°–50° and 50°–100°). However, the condition that exhibited the greatest angular velocity in combination with ROM (0°–100° at 200°/s) elicited the greatest increases in HR (+13 ± 2%; P < 0.05) and CO (+12 ± 2%; P < 0.05) compared with all conditions. Additionally, there was a significant relationship between MFL and HR within 0°–100° at 200°/s condition ( r2 = 0.59; P < 0.05). These findings suggest that increasing MFL and joint ROM in combination with increased angular velocity via PLM are important components that activate mechanoreflex-mediated cardioacceleration and increased CO. NEW & NOTEWORTHY The mechanoreflex is an important autonomic feedback mechanism that serves to optimize skeletal muscle perfusion during exercise. The present study sought to explore the mechanistic contributions that initiate the mechanoreflex using passive leg movement (PLM). The novel findings show that progressively increasing joint angle range of motion and muscle fascicle length via PLM, in combination with increased angular velocity, are important components that activate mechanoreflex-mediated cardioacceleration and increase cardiac output in humans.

Gyroscope-Free Link Parameter Measurement Using Accelerometers and Magnetometer

2014 ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Angular Velocity ◽  
Joint Angle ◽  
Inertial Sensors ◽  
Angular Acceleration ◽  
Parameter Measurement ◽  
Joint Angles ◽  
Symmetry Constraint ◽  
Estimation Techniques ◽  
Angular Velocities ◽  
Joint Parameters

Knowledge of joint angles, angular velocities is essential for control of link mechanisms and robots. The estimation of joint angles and angular velocity is performed using combination of inertial sensors (accelerometers and gyroscopes) which are contactless and flexible at point of application. Different estimation techniques are used to fuse data from different inertial sensors. Bio-inspired sensors using symmetrically placed multiple inertial sensors are capable of instantaneously measuring joint parameters (joint angle, angular velocities and angular acceleration) without use of any estimation techniques. Calibration of inertial sensors is easier and more reliable for accelerometers as compared to gyroscopes. The research presents gyroscope-less, multiple accelerometer and magnetometer based sensors capable of measuring (not estimating) joint parameters. The contribution of the improved sensor are four-fold. Firstly, the inertial sensors are devoid of symmetry constraint unlike the previously researched bio-inspired sensors. However, the accelerometer are non-coplanarly placed. Secondly, the accelerometer-magnetometer combination sensor allows for calculation of a unique rotation matrix between two link joined by any kind of joint. Thirdly, the sensors are easier to calibrate as they consist only of accelerometers. Finally, the sensors allow for calculation of angular velocity and angular acceleration without use of gyroscopes.

scholarly journals Pressure based MRI-compatible muscle fascicle length and joint angle estimation

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Hyungeun Song ◽  
Erica Israel ◽  
Shriya Srinivasan ◽  
Hugh Herr
Keyword(s):  
Joint Angle ◽  
Fascicle Length ◽  
Angle Estimation ◽  
Muscle Fascicle

In vivo estimation of contraction velocity of human vastus lateralis muscle during “isokinetic” action

2000 ◽  
Vol 88 (3) ◽  
pp. 851-856 ◽  
Author(s):  
Y. Ichinose ◽  
Y. Kawakami ◽  
M. Ito ◽  
H. Kanehisa ◽  
T. Fukunaga
Keyword(s):  
Angular Velocity ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Vastus Lateralis Muscle ◽  
Shortening Velocity ◽  
Full Extension ◽  
Fascicle Length ◽  
Lateralis Muscle ◽  
Angular Velocities

To determine the shortening velocities of fascicles of the vastus lateralis muscle (VL) during isokinetic knee extension, six male subjects were requested to extend the knee with maximal effort at angular velocities of 30 and 150°/s. By using an ultrasonic apparatus, longitudinal images of the VL were produced every 30 ms during knee extension, and the fascicle length and angle of pennation were obtained from these images. The shortening fascicle length with extension of the knee (from 98 to 13° of knee angle; full extension = 0°) was greater (43 mm) at 30°/s than at 150°/s (35 mm). Even when the angular velocity remained constant during the isokinetic range of motion, the fascicle velocity was found to change from 39 to 77 mm/s at 150°/s and from 6 to 19 mm/s at 30°/s. The force exerted by a fascicle changed with the length of the fascicle at changing angular velocities. The peak values of fascicle force and velocity were observed at ∼90 mm of fascicle length. In conclusion, even if the angular velocity of knee extension is kept constant, the shortening velocity of a fascicle is dependent on the force applied to the muscle-tendon complex, and the phenomenon is considered to be caused mainly by the elongation of the elastic element (tendinous tissue).

Design of an Automated Device to Measure Sagittal Plane Stiffness of an Articulated Ankle-Foot Orthosis

2010 ◽  
Vol 34 (4) ◽  
pp. 439-448 ◽  
Author(s):  
Toshiki Kobayashi ◽  
Aaron k. L. Leung ◽  
Yasushi Akazawa ◽  
Hisashi Naito ◽  
Masao Tanaka ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Range Of Motion ◽  
Fatigue Testing ◽  
Sagittal Plane ◽  
Testing Machine ◽  
Ankle Foot Orthosis ◽  
Resistive Torque ◽  
Angular Velocities ◽  
Rotary Plate ◽  
Foot Orthosis

The purpose of this study was to design a new automated stiffness measurement device which could perform a simultaneous measurement of both dorsi- and plantarflexion angles and the corresponding resistive torque around the rotational centre of an articulated ankle-foot orthosis (AAFO). This was achieved by controlling angular velocities and range of motion in the sagittal plane. The device consisted of a hydraulic servo fatigue testing machine, a torque meter, a potentiometer, a rotary plate and an upright supporter to enable an AAFO to be attached to the device via a surrogate shank. The accuracy of the device in reproducing the range of motion and angular velocity was within 4% and 1% respectively in the range of motion of 30&dG (15&dG plantarflexion to 15&dG dorsiflexion) at the angular velocity of 10&dG /s, while that in the measurement of AAFO torque was within 8% at the 0&dG position. The device should prove useful to assist an orthotist or a manufacturer to quantify the stiffness of an AAFO and inform its clinical use.

Static Stretching Intensity Does Not Influence Acute Range of Motion, Passive Torque, and Muscle Architecture

2020 ◽  
Vol 29 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Camila Ximenes Santos ◽  
Natália Barros Beltrão ◽  
André Luiz Torres Pirauá ◽  
João Luiz Quagliotti Durigan ◽  
David Behm ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Range Of Motion ◽  
Pennation Angle ◽  
Muscle Architecture ◽  
Fascicle Length ◽  
Passive Torque ◽  
Muscle Fascicle ◽  
Viscoelastic Stress Relaxation ◽  
Stretching Intensity ◽  
Stretching Exercises

Context: Although stretching exercises are commonly used in clinical and athletic practice, there is a lack of evidence regarding the methodological variables that guide the prescription of stretching programs, such as intensity. Objective: To investigate the acute effects of different stretching intensities on the range of motion (ROM), passive torque, and muscle architecture. Design: Two-group pretest–posttest design. Setting: Laboratory. Participants: Twenty untrained men were allocated into the low- or high-intensity group. Main Outcome Measures: Subjects were evaluated for initial (ROMinitial) and maximum (ROMmax) discomfort angle, stiffness, viscoelastic stress relaxation, muscle fascicle length, and pennation angle. Results: The ROM assessments showed significant changes, in both groups, in the preintervention and postintervention measures both for the ROMinitial (P < .01) and ROMmax angle (P = .02). There were no significant differences for stiffness and viscoelastic stress relaxation variables. The pennation angle and muscle fascicle length were different between the groups, but there was no significant interaction. Conclusion: Performing stretching exercises at high or low intensity acutely promotes similar gains in flexibility, that is, there are short-term/immediate gains in ROM but does not modify passive torque and muscle architecture.

The Effect of External Compression on the Mechanics of Muscle Contraction

2013 ◽  
Vol 29 (3) ◽  
pp. 360-364 ◽  
Author(s):  
James M. Wakeling ◽  
Meghan Jackman ◽  
Ana I. Namburete
Keyword(s):  
Muscle Thickness ◽  
Muscle Performance ◽  
Medial Gastrocnemius ◽  
Shortening Velocity ◽  
Fascicle Length ◽  
External Compression ◽  
Muscle Belly ◽  
Compression Bandages ◽  
Muscle Fascicle ◽  
Angular Velocities

The velocity at which a muscle fascicle will shorten, and hence the force that it can develop, depends on its gearing within the muscle belly. Muscle fascicle length depends on both its pennation and the thickness of the muscle. It was expected that external compression would reduce the muscle thickness and pennation and thus cause a reduction to the gearing of the fascicles relative to the muscle belly. Structural properties of the medial gastrocnemius muscle were visualized using B-mode ultrasound in six subjects. Measurements were taken during cyclical isotonic contractions at three different ankle torques and with the application of no, one, or two elastic compression bandages to the lower leg. Ankle torques and angular velocities were unaffected by the external compression. External compression did, however, reduce the muscle thickness and the fascicle pennation and resulted in a decrease in the gearing within the muscle belly. Reductions in gearing would result in an increase in the muscle fascicle shortening velocity that would reduce the force-generating potential of the fascicles. It is suggested that externally applied compression should not be considered a way to enhance muscle performance when based on the structural mechanics.

scholarly journals Association between medial gastrocnemius muscle-tendon unit architecture and ankle dorsiflexion range of motion with and without consideration of slack angle

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248125
Author(s):  
Kosuke Hirata ◽  
Hiroaki Kanehisa ◽  
Naokazu Miyamoto
Keyword(s):  
Shear Modulus ◽  
Range Of Motion ◽  
Ankle Joint ◽  
Joint Angle ◽  
Pennation Angle ◽  
Medial Gastrocnemius ◽  
Fascicle Length ◽  
Joint Flexibility ◽  
Anatomical Position ◽  
Maximal Angle

Joint flexibility is theoretically considered to associate with muscle-tendon unit (MTU) architecture. However, this potential association has not been experimentally demonstrated in humans in vivo. We aimed to identify whether and how MTU architectural parameters are associated with joint range of motion (RoM), with a special emphasis on slack angle. The fascicle length, pennation angle, tendinous tissue length, MTU length, and shear modulus of the medial gastrocnemius (MG) were assessed during passive ankle dorsiflexion using ultrasound shear wave elastography in 17 healthy males. During passive dorsiflexion task, the ankle joint was rotated from 40° plantar flexion to the maximal dorsiflexion joint angle at which each subject started experiencing pain. From the ankle joint angle-shear modulus relationship, the angle at which shear modulus began to rise (slack angle) was calculated. Two dorsiflexion RoMs were determined as follows; 1) range from the anatomical position to maximal angle (RoManat-max) and 2) range from the MG slack angle to maximal angle (RoMslack-max). The MTU architectural parameters were analyzed at the anatomical position and MG slack angle. The resolved fascicle length (fascicle length × cosine of pennation angle) and ratios of resolved fascicle or tendinous tissue length to MTU length measured at the MG slack angle significantly correlated with the RoMslack-max (r = 0.491, 0.506, and -0.506, respectively). Any MTU architectural parameters assessed at the anatomical position did not correlate with RoManat-max or RoMslack-max. These results indicate that MTUs with long fascicle and short tendinous tissue are advantageous for joint flexibility. However, this association cannot be found unless MTU architecture and joint RoM are assessed with consideration of muscle slack.

Dynamic Effects of Muscle Moment Arm Variation and Heavy External Loads on Hinge Joints

2003 ◽  
Vol 19 (3) ◽  
pp. 223-238 ◽  
Author(s):  
Andrea Biscarini
Keyword(s):  
Angular Velocity ◽  
Range Of Motion ◽  
External Load ◽  
Joint Angle ◽  
Joint Modeling ◽  
Moment Arm ◽  
Moment Arms ◽  
Flexion Extension ◽  
External Loads ◽  
Load Weight

A two-dimensional model has been developed to predict and explain the effects of the variation of muscle moment arms during dynamic exercises involving heavy external loads. The analytical dependence of the muscle moment arm on the joint angle and on the origin and insertion position was derived for an ideal uniaxial hinge joint, modeling the muscle as a cable following an idealized minimum distance path from the origin to insertion that wraps around the bony geometry. Analytical expressions for the ratios of muscular force and the joint restraining reaction components to the external load weight were deduced, for isokinetic and static exercises, as a function of joint angle, joint angular velocity, and the other geometric parameters defining the model. Therefore, external load weight, joint angular velocity, and constraints to joint range of motion may be adjusted reciprocally in order to control in advance the peak value of the components of the joint load during isokinetic exercises. A dynamic formulation of forearm flexion/extension was solved numerically under the condition of constant biceps force in order to highlight the key role played by the variation in muscle moment arm in preventing injury during lifting of external loads against gravity. For example, our analysis indicates that the mean and peak resultant joint loads decrease by 5% and 14%, respectively, as a result of the change in muscle moment arm that occurs over the range of motion.

The Analysis of Proprioception Alteration during First Five Months after Anterior Cruciate Ligament Reconstruction

2018 ◽  
Vol 1 (84) ◽  
Author(s):  
Vilma Jurevičienė ◽  
Albertas Skurvydas ◽  
Juozas Belickas ◽  
Giedra Bušmanienė ◽  
Dovilė Kielė ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Angular Velocity ◽  
Knee Joint ◽  
Cruciate Ligament ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Starting Position ◽  
Angular Velocities ◽  
Anterior Cruciate

Research  background  and  hypothesis.  Proprioception  is  important  in  the  prevention  of  injuries  as  reduced proprioception  is  one  of  the  factors  contributing  to  injury  in  the  knee  joint,  particularly  the  ACL.  Therefore, proprioception appears not only important for the prevention of ACL injuries, but also for regaining full function after ACL reconstruction.Research aim. The aim of this study was to understand how proprioception is recovered four and five months after anterior cruciate ligament (ACL) reconstruction.Research methods. The study included 15 male subjects (age – 33.7 ± 2.49 years) who had undergone unilateral ACL reconstruction with a semitendinosus/gracilis (STG) graft in Kaunas Clinical Hospital. For proprioceptive assessment, joint position sense (JPS) was measured on both legs using an isokinetic dynamometer (Biodex), at knee flexion of 60° and 70°, and at different knee angular velocities of 2°/s and 10°/s. The patients were assessed preoperatively and after 4 and 5 months, postoperatively.Research results. Our study has shown that the JPS’s (joint position sense) error scores  to a controlled active movement is significantly higher in injured ACL-deficient knee than in the contralateral knee (normal knee) before surgery and after four and five months of rehabilitation.  After 4 and 5 months of rehabilitation we found significantly lower values in injured knees compared to the preoperative data. Our study has shown that in injured knee active angle reproduction errors after 4 and 5 months of rehabilitation were higher compared with the ones of the uninjured knee. Proprioceptive ability on the both legs was  independent of all differences angles for target and starting position for movement. The knee joint position sense on both legs depends upon the rate of two different angular velocities and the mean active angle reproduction errors at the test of angular velocity slow speed was the highest compared with the fast angular velocity. Discussion and conclusions. In conclusion, our study shows that there was improvement in mean JPS 4 and 5 months after ACL reconstruction, but it did not return to normal indices.Keywords: knee joint, joint position sense, angular velocity, starting position for movement.

Finite difference code for velocity and surface traction of a Fluid between Two Eccentric Spheres

2015 ◽  
Vol 11 (1) ◽  
pp. 2960-2971
Author(s):  
M.Abdel Wahab
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Finite Difference ◽  
Numerical Study ◽  
Outer Sphere ◽  
Equation Of Motion ◽  
Annular Region ◽  
Surface Traction ◽  
Angular Velocities ◽  
Axis Passing

The Numerical study of the flow of a fluid in the annular region between two eccentric sphere susing PHP Code isinvestigated. This flow is created by considering the inner sphere to rotate with angular velocity 1  and the outer sphererotate with angular velocity 2  about the axis passing through their centers, the z-axis, using the three dimensionalBispherical coordinates (, ,) .The velocity field of fluid is determined by solving equation of motion using PHP Codeat different cases of angular velocities of inner and outer sphere. Also Finite difference code is used to calculate surfacetractions at outer sphere.

Sign in / Sign up

Export Citation Format

Share Document