Reconstruction of the Human Gastrocnemius Force–Length Curve in Vivo: Part 2—Experimental Results

2008 ◽  
Vol 24 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Samantha L. Winter ◽  
John H. Challis
Keyword(s):  
Muscle Fiber ◽  
Plantar Flexion ◽  
Experimental Results ◽  
Joint Motion ◽  
Plateau Region ◽  
Length Relationship ◽  
Relationship Of ◽  
Muscle Models ◽  
Muscle Property

For a physiologically realistic range of joint motion and therefore range of muscle fiber lengths, only part of the force-length curve can be used in vivo; i.e., the section of the force–length curve that is expressed can vary. The purpose of this study was to determine the expressed section of the force–length relationship of the gastrocnemius for humans. Fourteen male and fourteen female subjects aged 18–27 performed maximal isometric plantar flexions in a Biodex dynamometer. Plantar flexion moments were recorded at five ankle angles: −15°, 0°, 15°, 30°, and 40°, with negative angles defined as dorsiflexion. These measurements were repeated for four randomly ordered knee angles over two testing sessions 4 to 10 days apart. The algorithm of Herzog and ter Keurs (1988a) was used to reconstruct the force–length curves of the biarticular gastrocnemius. Twenty-four subjects operated over the ascending limb, three operated over the descending limb, and one operated over the plateau region. The variation found suggests that large subject groups should be used to determine the extent of normal in vivo variability in this muscle property. The possible source of the variability is discussed in terms of parameters typically used in muscle models.

Differences Between Principal Strain Directions and Muscle Fiber Directions in the Contracting Biceps Bracii Measured With CPC-MRI

2007 ◽  
Author(s):  
Hehe Zhou ◽  
John E. Novotny
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Biceps Brachii ◽  
Principal Strain ◽  
Strain Fields ◽  
Ultrasound Study ◽  
Lagrangian Strain ◽  
Novel Method ◽  
Muscle Models

Skeletal muscle exhibit non-uniform internal architectures and our research goals are to relate these to their internal mechanics during contraction to provide a better understanding of muscle function, verify muscle models and permit more sophisticated interpretation of the functional effects of injury. Our previous studies have developed a novel method to calculate 2D Lagrangian strain field of skeletal muscle from the CPC-MRI [1]. The objective of this study is to apply CPC-MRI to derive Lagrangian strain fields for the normal biceps brachii and to determine its minimum principal strain directions in vivo during contraction. We will then compare them to the muscle fiber directions or pennation angles measured by a parallel ultrasound study. If we assume the muscle force is mainly transmitted along fiber directions, we would expect that the minimum principal strain directions are the same as fiber directions. Comparisons between different regions of the muscle and flexion angles will also be made.

Architecture of Contracting Human Muscles and Its Functional Significance

2000 ◽  
Vol 16 (1) ◽  
pp. 88-97 ◽  
Author(s):  
Yasuo Kawakami ◽  
Yoshiho Ichinose ◽  
Keitaro Kubo ◽  
Masamitsu Ito ◽  
Morihiro Imai ◽  
...  
Keyword(s):  
Plantar Flexion ◽  
Muscle Thickness ◽  
Normal Subjects ◽  
Human Muscle ◽  
Muscle Architecture ◽  
Triceps Brachii ◽  
Fascicle Length ◽  
Ultrasonic Images ◽  
Relationship Of

This paper reviews three of our recent studies on human muscle architecture in vivo. 1. Hypertrophic changes: From B-mode ultrasonograms, pennation angles and thickness of triceps brachii were determined for normal subjects and highly-trained bodybuilders. There was a significant correlation between muscle thickness and pennation angles. It was confirmed that hypertrophy was accompanied by an increase in pennation angles. 2. Variation of fascicle architecture: Fascicle lengths and pennation angles were obtained from different positions in the gastrocnemius muscle while the subjects relaxed and performed isometric plantar flexion. The fascicle length was uniform throughout the muscle and shortened by contraction (30-34% at 50% of the maximal force). On the other hand, pennation angles differed among positions and increased by contraction. The muscle thickness did not change by contraction. Pen-nation angles were significantly correlated with muscle thickness within muscle. 3. Joint position-fascicle length relationships: Ultrasonic images of the gastrocnemius and soleus muscles were obtained while the subject performed maximal isometric plantarflexion at various joint positions, from which fascicle lengths and angles were determined. The length-force relationship of each muscle was estimated. It was suggested that human muscle architecture has an ability to make substantial changes to adapt to environmental conditions.

Reconstruction of the Human Gastrocnemius Force–Length Curve in Vivo: Part 1—Model-Based Validation of Method

2008 ◽  
Vol 24 (3) ◽  
pp. 197-206 ◽  
Author(s):  
Samantha L. Winter ◽  
John H. Challis
Keyword(s):  
Muscle Fiber ◽  
Muscle Activation ◽  
Gastrocnemius Muscle ◽  
Simulated Data ◽  
Triceps Surae ◽  
Sampling Errors ◽  
Length Relationship ◽  
Biarticular Muscles ◽  
Systematic Noise

The muscle fiber force–length relationship has been explained in terms of the cross-bridge theory at the sarcomere level. In vivo, for a physiologically realistic range of joint motion, and therefore range of muscle fiber lengths, only part of the force–length curve may be used; that is, the section of the force– length curve expressed can vary. The purpose of this study was to assess the accuracy of a method for determining the expressed section of the force– length curve for biarticular muscles. A muscle model was used to simulate the triceps surae muscle group. Three model formulations were used so that the gastrocnemius operated over different portions of the force–length curve: the ascending limb, the plateau region, and the descending limb. Joint moment data were generated for a range of joint configurations and from this simulated data the region of the force– length relationship that the gastrocnemius muscle operated over was successfully reconstructed using the algorithm of Herzog and ter Keurs (1988a). Further simulations showed that the correct region of the force–length curve was accurately reconstructed even in the presence of random and systematic noise generated to reflect the effects of sampling errors, and incomplete muscle activation.

Force-length relationship of the normal human diaphragm

1982 ◽  
Vol 53 (2) ◽  
pp. 405-412 ◽  
Author(s):  
N. M. Braun ◽  
N. S. Arora ◽  
D. F. Rochester
Keyword(s):  
Chest Wall ◽  
Normal Subjects ◽  
X Rays ◽  
Length Relationship ◽  
Diaphragm Position ◽  
Lower Lung ◽  
Normal Human ◽  
Volume Relation ◽  
Relationship Of

To characterize the in vivo force-length relation of the human diaphragm, we related pressures during static inspiratory efforts (Pmus and Pdi, respiratory muscle and transdiaphragmatic pressures, respectively) to diaphragm lengths measured on chest X rays from 22 normal subjects. At total lung capacity, the intersection of diaphragm and chest wall contours corresponds to the anatomic junction of diaphragm and chest wall. This point is located by skeletal landmarks to reveal the entire diaphragm contour on films taken at lower lung volumes. To validate the X-ray measurements, corresponding diameters were measured on 32 normal diaphragms at necropsy. After correction for height and diaphragm position, in vivo and necropsy length estimates along the coronal section agreed within 9%. The diaphragm length-lung volume relation is curvilinear, with length increasing primarily in the portion of the diaphragm apposed to the chest wall. As length increases, Pmus and Pdi rise sharply then plateau, generally conforming to force-length behavior of isolated muscle. However, absence of a Pdi peak at presumed diaphragm resting length suggests that Pdi is submaximal during voluntary inspiratory effort.

scholarly journals Bite force is limited by the force–length relationship of skeletal muscle in black carp, Mylopharyngodon piceus

2013 ◽  
Vol 9 (2) ◽  
pp. 20121181 ◽  
Author(s):  
Nicholas J. Gidmark ◽  
Nicolai Konow ◽  
Eric LoPresti ◽  
Elizabeth L. Brainerd
Keyword(s):  
Skeletal Muscle ◽  
Prey Size ◽  
Muscle Length ◽  
Bite Force ◽  
Black Carp ◽  
Length Relationship ◽  
Mylopharyngodon Piceus ◽  
Relationship Of ◽  
Pharyngeal Jaw

Bite force is critical to feeding success, especially in animals that crush strong, brittle foods. Maximum bite force is typically measured as one value per individual, but the force–length relationship of skeletal muscle suggests that each individual should possess a range of gape height-specific, and, therefore, prey size-specific, bite forces. We characterized the influence of prey size on pharyngeal jaw bite force in the snail-eating black carp ( Mylopharyngodon piceus, family Cyprinidae), using feeding trials on artificial prey that varied independently in size and strength. We then measured jaw-closing muscle lengths in vivo for each prey size, and then determined the force–length relationship of the same muscle in situ using tetanic stimulations. Maximum bite force was surprisingly high: the largest individual produced nearly 700 N at optimal muscle length. Bite force decreased on large and small prey, which elicited long and short muscle lengths, respectively, demonstrating that the force–length relationship of skeletal muscle results in prey size-specific bite force.

scholarly journals Force Generation on the Hallux Is More Affected by the Ankle Joint Angle than the Lesser Toes: An In Vivo Human Study

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 48
Author(s):  
Junya Saeki ◽  
Soichiro Iwanuma ◽  
Suguru Torii
Keyword(s):  
Repeated Measures ◽  
Joint Angle ◽  
Plantar Flexion ◽  
Human Study ◽  
Force Generation ◽  
Functional Difference ◽  
Multiple Comparison Test ◽  
The Difference ◽  
Metatarsophalangeal Joints

The structure of the first toe is independent of that of the other toes, while the functional difference remains unclear. The purpose of this study was to investigate the difference in the force generation characteristics between the plantar-flexion of the first and second–fifth metatarsophalangeal joints (MTPJs) by comparing the maximal voluntary plantar-flexion torques (MVC torque) at different MTPJs and ankle positions. The MVC torques of the first and second–fifth MTPJs were measured at 0°, 15°, 30°, and 45° dorsiflexed positions of the MTPJs, and at 20° plantar-flexed, neutral, and 20° dorsiflexed positions of the ankle. Two-way repeated measures analyses of variance with Holm’s multiple comparison test (MTPJ position × ankle position) were performed. When the MTPJ was dorsiflexed at 0°, 15°, and 30°, the MVC torque of the first MTPJ when the ankle was dorsiflexed at 20° was higher than that when the ankle was plantar-flexed at 20°. However, the ankle position had no significant effect on the MVC torque of the second–fifth MTPJ. Thus, the MVC torque of the first MTPJ was more affected by the ankle position than the second–fifth MTPJs.

scholarly journals Actin and Microtubules Differently Contribute to Vacuolar Targeting Specificity during the Export from the ER

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 299
Author(s):  
Monica De Caroli ◽  
Fabrizio Barozzi ◽  
Luciana Renna ◽  
Gabriella Piro ◽  
Gian-Pietro Di Sansebastiano
Keyword(s):  
Spatial Targeting ◽  
Traffic Regulation ◽  
Emergent Features ◽  
Vacuolar Sorting ◽  
Er Export ◽  
Golgi Network ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Tune

Plants rely on both actin and microtubule cytoskeletons to fine-tune sorting and spatial targeting of membranes during cell growth and stress adaptation. Considerable advances have been made in recent years in the comprehension of the relationship between the trans-Golgi network/early endosome (TGN/EE) and cytoskeletons, but studies have mainly focused on the transport to and from the plasma membrane. We address here the relationship of the cytoskeleton with different endoplasmic reticulum (ER) export mechanisms toward vacuoles. These emergent features of the plant endomembrane traffic are explored with an in vivo approach, providing clues on the traffic regulation at different levels beyond known proteins’ functions and interactions. We show how traffic of vacuolar markers, characterized by different vacuolar sorting determinants, diverges at the export from the ER, clearly involving different components of the cytoskeleton.

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