The Force-Length Curves of the Human Rectus Femoris and Gastrocnemius Muscles in Vivo

2010 ◽  
Vol 26 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Samantha L. Winter ◽  
John H. Challis
Keyword(s):  
Muscle Fiber ◽  
Rectus Femoris ◽  
Trained Subjects ◽  
Joint Range Of Motion ◽  
Angle Data ◽  
Slack Length ◽  
Gastrocnemius Muscles ◽  
Joint Range ◽  
Whole Muscle

For a physiologically realistic joint range of motion and therefore range of muscle fiber lengths, only part of the whole muscle force-length curve can be used in vivo; that is, only a section of the force-length curve is expressed. Previous work has determined that the expressed section of the force-length curve for individual muscles can vary between subjects; however, the degree of intersubject variability is different for different muscles. This study determined the expressed section of both the rectus femoris and gastrocnemius—muscles with very different ratios of tendon slack length to muscle fiber optimum length—for 28 nonspecifically trained subjects to test the hypothesis that the value of this ratio affects the amount of variability in the expressed section. The force-length curves of the two muscles were reconstructed from moment-angle data using the method of Herzog & ter Keurs (1988). There was no relationship between the expressed sections of the force-length curve for the two muscles. Less variability was found in the expressed section of the gastrocnemius compared with the rectus femoris, supporting the hypothesis. The lack of relationship between the expressed sections of the two muscles has implications for motor control and for training muscle for rehabilitation.

Muscle fiber number in biceps brachii in bodybuilders and control subjects

1984 ◽  
Vol 57 (5) ◽  
pp. 1399-1403 ◽  
Author(s):  
J. D. MacDougall ◽  
D. G. Sale ◽  
S. E. Alway ◽  
J. R. Sutton
Keyword(s):  
Muscle Fiber ◽  
Biceps Brachii ◽  
Cross Sectional Area ◽  
Muscle Size ◽  
Sectional Area ◽  
Cross Sectional ◽  
Trained Subjects ◽  
Fiber Area ◽  
Muscle Cross Sectional Area

Muscle fiber numbers were estimated in vivo in biceps brachii in 5 elite male bodybuilders, 7 intermediate caliber bodybuilders, and 13 age-matched controls. Mean fiber area and collagen volume density were calculated from needle biopsies and muscle cross-sectional area by computerized tomographic scanning. Contralateral measurements in a subsample of seven subjects indicated the method for estimation of fiber numbers to have adequate reliability. There was a wide interindividual range for fiber numbers in biceps (172,085–418,884), but despite large differences in muscle size both bodybuilder groups possessed the same number of muscle fibers as the group of untrained controls. Although there was a high correlation between average cross-sectional fiber area and total muscle cross-sectional area within each group, many of the subjects with the largest muscles also tended to have a large number of fibers. Since there were equally well-trained subjects with fewer than normal fiber numbers, we interpret this finding to be due to genetic endowment rather than to training-induced hyperplasia. The proportion of muscle comprised of connective and other noncontractile tissue was the same for all subjects (approximately 13%), thus indicating greater absolute amounts of connective tissue in the trained subjects. We conclude that in humans, heavy resistance training directed toward achieving maximum size in skeletal muscle does not result in an increase in fiber numbers.

scholarly journals Ezrin Prompted Myoblast Differentiation and Muscle Fiber Specialization and Gastrocnemius Muscle Repair in Peroneal Nerve Injury Model through PKA-NFATs Signaling Pathway

2021 ◽  
Author(s):  
Ruo-nan Zhang ◽  
Xin Bao ◽  
Yan Wang ◽  
Xin-Yuan Li ◽  
MagdaleenaNaemi Mbadhi ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Muscle Fiber ◽  
Peroneal Nerve ◽  
Gastrocnemius Muscle ◽  
Myoblast Differentiation ◽  
Inhibitory Effects ◽  
Injury Model ◽  
Peroneal Nerve Injury ◽  
Gastrocnemius Muscles

Abstract Background: Muscular dystrophy is a destructive neuromuscular disease characterized by progressive muscle weakness and muscle atrophy. The role of Ezrin in myoblast differentiation/fusion and muscle atrophy is still unknown.Method: Gastrocnemius muscle atrophy model were prepared by mechanical clamp of peroneal nerve. Differentiating C2C12 cells treated with Ad-Ezrin or Ad-shEzrin were detected by gene chip, Q-PCR, immunofluorescence staining and Western blot.Results: Ezrin was expressed in MyHC I/II myofibers in vivo, and time-dependently increased during myoblast differentiation/fusion characterized by MyoG+/MEF2c nuclei and MyHC+ myotubes in vitro. Overexpression of Ezrin promoted myoblast differentiation/fusion in time-dependent manner, inducing the increased MyHC-I+ and MyHC-II+ muscle fiber specialization, the specific effects could be abolished by addition of Ad-Periaxin. Ad-Ezrin did not alter PKA and PKAreg II α levels, but PKAreg I α/β. The PKA inhibitor, H-89, remarkably abolished the over-expression effects by Ezrin on an increased myoblast differentiation/fusion. By contrast, Knockdown of Ezrin by shRNA significantly delayed myoblast differentiation/fusion accompanied by the decreased PKA reg I/II ratio, the inhibitory effects could be eliminated by PKAreg I activator N6-Bz-cAMP. Meanwhile, Ad-Ezrin enhanced type I muscle fiber specialization, accompanied by the increased levels of NFATc1/c2.Furthermore, Ad-NFATc2 or Ad-NFATc4 reversed the inhibitory effects of Ad-shEzrin on myoblast differentiation/fusion. Importantly, in vivo transfection of Ad-Ezrin into gastrocnemius muscles in peroneal nerve injury model increased the numbers of MyHC-I+ and MyHC-II+ myofibers, reducing muscle atrophy and fibrosis.Conclusions: Ezrin activated PKA-NFAT-MyoD/MyoG/MEF2C signaling pathway, triggering myoblast differentiation/fusion and muscle fiber specialization in periaxin-depentdent manner, contributing to gastrocnemius muscles repair.

Longitudinal Measurement of In-Vivo Tendon Function Over 17 Weeks Following Repair: Technique and Preliminary Results in a Canine Rotator Cuff Model

2007 ◽  
Author(s):  
Michael J. Bey ◽  
Stephanie K. Brock ◽  
Andrew R. Baker ◽  
Kathleen A. Derwin
Keyword(s):  
Rotator Cuff ◽  
Tendon Repair ◽  
Rotator Cuff Tears ◽  
X Ray ◽  
Longitudinal Measurement ◽  
Joint Range Of Motion ◽  
Normal Tendon ◽  
Joint Range

Rotator cuff tears are a common injury, affecting 30–40% of the population over age 60 and representing a tremendous source of pain and disability. Rotator cuff tears are often repaired surgically, but a significant percentage (perhaps 50% or more) of large cuff tears fail after surgery and result in long-term shoulder disability. The outcome of rotator cuff repair surgery is typically assessed by measuring muscle strength, joint range of motion, pain, and other subjective indicators of function. Although these types of measurements are used extensively, they provide only an indirect assessment of tendon function. We have recently developed new experimental techniques that allow us to use a biplane x-ray system to directly assess in-vivo tendon function. The purpose of this study was to assess the feasibility of using a biplane x-ray system to quantify changes in in-vivo tendon function following tendon repair in a canine rotator cuff model. We hypothesized that tendon function will improve over the healing period (as reflected by changes in measures of repair stiffness and contracture) and approach normal tendon function by 17 weeks.

Residual Force Enhancement in Humans: A Systematic Review

2018 ◽  
Vol 34 (3) ◽  
pp. 240-248 ◽  
Author(s):  
Neil Chapman ◽  
John Whitting ◽  
Suzanne Broadbent ◽  
Zachary Crowley-McHattan ◽  
Rudi Meir
Keyword(s):  
Isometric Contraction ◽  
Force Enhancement ◽  
Joint Range Of Motion ◽  
Prisma Statement ◽  
Residual Force ◽  
Residual Force Enhancement ◽  
English Articles ◽  
Joint Range ◽  
Muscular Activation

A systematic literature search was conducted to review the evidence of residual force enhancement (RFE) in vivo human muscle. The search, adhered to the PRISMA statement, of CINAHL, EBSCO, Embase, MEDLINE, and Scopus (inception—July 2017) was conducted. Full-text English articles that assessed at least 1 measure of RFE in vivo voluntarily contracted human skeletal muscle were selected. The methodologies of included articles were assessed against the Downs and Black checklist. Twenty-four studies were included (N = 424). Pooled Downs and Black scores ranked “fair” ( [2.26]). RFE was observed in all muscles tested. Joint range of motion varied from 15° to 60°. Contraction intensities ranged from 10% to >95% maximum. Although transient force enhancement during the stretch phase may change with angular velocity, RFE in the subsequent isometric phase is independent of velocity. The magnitude of RFE was influenced by smaller stretch amplitudes and greatest at joint angles indicative of longer muscle lengths. Contraction and activation intensity influenced RFE, particularly during the initial isometric contraction phase of a poststretch isometric contraction. RFE resulted in increased torque production, reduced muscular activation, and enhanced torque production when the neuromuscular system is weakened seen in an aged population.

The “Fight Bite” Saline Joint Loading Test: Effectiveness in Detecting Simulated Traumatic Metacarpophalangeal Arthrotomies

Hand ◽  
2022 ◽  
pp. 155894472110681
Author(s):  
Morad Chughtai ◽  
Joseph P. Scollan ◽  
Ahmed K. Emara ◽  
Ben Brej ◽  
Andrew Steckler ◽  
...  
Keyword(s):  
Contralateral Side ◽  
Load Test ◽  
Load Testing ◽  
Joint Loading ◽  
Loading Test ◽  
Joint Range Of Motion ◽  
Human Cadavers ◽  
The Mean ◽  
Joint Range

Background: The saline load test is routinely used to recognize other joints’ traumatic arthrotomies; however, there are currently no studies evaluating the novelty of this test for metacarpophalangeal joints (MCPJs). This study aimed to investigate the effectiveness and sensitivity of saline load testing in identifying the traumatic arthrotomies of the MCPJs using human cadavers. Methods: This was a cadaveric study of 16 hands (79 MCPJs). Traumatic arthrotomies were created using 11-blade stab-incisions, followed by blunt probing into the joint on the radial or ulnar side of the flexed MCPJs. A 3-mL syringe was used to inject intra-articular methylene-blue-dyed saline from the contralateral side. The volume at saline extravasation was recorded. Test sensitivity and factors influencing extravasation volume were assessed. Results: The mean (range) volume injected to identify arthrotomy of all MCPJs was 0.18 mL (0.1-0.4 mL). The mean volume to identify MCPJ arthrotomy of the thumb, index, long, ring, and small fingers was 0.16 mL (0.1-0.3 mL), 0.19 mL (0.1-0.3 mL), 0.21 mL (0.1-0.4 mL), 0.17 mL (0.1-0.3 mL), and 0.16 mL (0.1-0.3 mL), respectively. Cadaver age, laterality, and joint range of motion were not significantly associated with the injected volume at extravasation( P > .05, each). Injection volumes of 0.3 and 0.32 mL were required to detect arthrotomies at 95% and 99% sensitivities across all MCPJs. None of the MCPJs required > 0.4 mL to detect arthrotomy. Conclusions: Saline joint loading volumes to detect traumatic arthrotomy were similar for all MCPJs. Injection volumes of 0.32 mL is suggested for 99% sensitivity. Our findings provide the first report, to our knowledge, on intra-articular injection volumes expected to detect an arthrotomy of MCPJ. This is critical for further validation using in vivo clinical studies.

Arthroscopy in Arthrosis: Is It Worth it? A case Presentation

2018 ◽  
Vol 69 (8) ◽  
pp. 2232-2235
Author(s):  
Marius Moga ◽  
Mark Edward Pogarasteanu ◽  
Antoine Edu
Keyword(s):  
Clinical Status ◽  
Loose Body ◽  
Point Of View ◽  
The Other ◽  
Joint Range Of Motion ◽  
Objective Evidence ◽  
Before And After ◽  
Total Knee ◽  
Joint Range

The role of arthroscopy in incipient and mild arthrosis, even combined with proximal tibial ostetomy, is well known and well documented. On the other hand, its role in the treatment of advanced arthrosis of the large joints, especially the knee, is a subject of controversy. The proponents of the use of arthroscopy in advanced arthrosis claim that meniscectomy, synovectomy, ostophytectomy, chondral lesion stabilization, arthroscopic release, plica and loose body removal greatly improve the quality of life for most patients, especially if followed by the use of viscoelastic injection, by diminishing pain and improving joint range of motion. The opponents claim that, even though the advantages are clear in the cases that refuse arthroplasty, in all the other cases the surgical indication should be total knee arthroplasty, as the clinical relief is temporary, but with all the risks of a surgical intervention. We have conducted an overview of the recent literature, in order to find objective evidence to sustain either point of view. We focused on articles published that included an objective measurement of before and after clinical status through clinical scores and objective measurements. We also focused on the follow-up period and on the evolution of the pathology after arthroscopy.

scholarly journals Rectus Femoris Mimicking Ultrasound Phantom for Muscle Mass Assessment: Design, Research, and Training Application

2021 ◽  
Vol 10 (12) ◽  
pp. 2721
Author(s):  
Nobuto Nakanishi ◽  
Shigeaki Inoue ◽  
Rie Tsutsumi ◽  
Yusuke Akimoto ◽  
Yuko Ono ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Rectus Femoris ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Phantom Model ◽  
Ultrasound Measurements ◽  
Ultrasound Phantom

Ultrasound has become widely used as a means to measure the rectus femoris muscle in the acute and chronic phases of critical illness. Despite its noninvasiveness and accessibility, its accuracy highly depends on the skills of the technician. However, few ultrasound phantoms for the confirmation of its accuracy or to improve technical skills exist. In this study, the authors created a novel phantom model and used it for investigating the accuracy of measurements and for training. Study 1 investigated how various conditions affect ultrasound measurements such as thickness, cross-sectional area, and echogenicity. Study 2 investigated if the phantom can be used for the training of various health care providers in vitro and in vivo. Study 1 showed that thickness, cross-sectional area, and echogenicity were affected by probe compression strength, probe angle, phantom compression, and varying equipment. Study 2 in vitro showed that using the phantom for training improved the accuracy of the measurements taken within the phantom, and Study 2 in vivo showed the phantom training had a short-term effect on improving the measurement accuracy in a human volunteer. The new ultrasound phantom model revealed that various conditions affected ultrasound measurements, and phantom training improved the measurement accuracy.

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