scholarly journals Architecture of the Short External Rotator Muscles of the Hip

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Kevin C. Parvaresh ◽  
Charles Chang ◽  
Ankur Patel ◽  
Richard L. Lieber ◽  
Scott T. Ball ◽  
...  
Keyword(s):  
Fiber Length ◽  
Short Fiber ◽  
Pennation Angle ◽  
Muscle Architecture ◽  
Small Individual ◽  
Cross Sectional ◽  
Short External Rotator ◽  
Gluteus Minimus ◽  
Obturator Internus ◽  
External Rotator

Abstract Background Muscle architecture, or the arrangement of sarcomeres and fibers within muscles, defines functional capacity. There are limited data that provide an understanding of hip short external rotator muscle architecture. The purpose of this study was thus to characterize the architecture of these small hip muscles. Methods Eight muscles from 10 independent human cadaver hips were used in this study (n = 80 muscles). Architectural measurements were made on pectineus, piriformis, gemelli, obturators, quadratus femoris, and gluteus minimus. Muscle mass, fiber length, sarcomere length, and pennation angle were used to calculate the normalized muscle fiber length, which defines excursion, and physiological cross-sectional area (PCSA), which defines force-producing capacity. Results Gluteus minimus had the largest PCSA (8.29 cm2) followed by obturator externus (4.54 cm2), whereas superior gemellus had the smallest PCSA (0.68 cm2). Fiber lengths clustered into long (pectineus - 10.38 cm and gluteus minimus - 10.30 cm), moderate (obturator internus - 8.77 cm and externus - 8.04 cm), or short (inferior gemellus - 5.64 and superior gemellus - 4.85). There were no significant differences among muscles in pennation angle which were all nearly zero. When the gemelli and obturators were considered as a single functional unit, their collective PCSA (10.00 cm2) exceeded that of gluteus minimus as a substantial force-producing group. Conclusions The key findings are that these muscles have relatively small individual PCSAs, short fiber lengths, and low pennation angles. The large collective PCSA and short fiber lengths of the gemelli and obturators suggest that they primarily play a stabilizing role rather than a joint rotating role.

scholarly journals The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint

2016 ◽  
Vol 52 (1) ◽  
pp. 12-23 ◽  
Author(s):  
Ran S Sopher ◽  
Andrew A Amis ◽  
D Ceri Davies ◽  
Jonathan RT Jeffers
Keyword(s):  
Pennation Angle ◽  
Muscle Architecture ◽  
Cross Sectional Area ◽  
Contact Forces ◽  
Sectional Area ◽  
Muscle Forces ◽  
Cross Sectional ◽  
Contact Loads ◽  
The Mean ◽  
And Function

Data about a muscle’s fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function.

A Numerical Method for Estimating Tendon Slack Length

2003 ◽  
Author(s):  
Kurt Manal ◽  
Thomas S. Buchanan
Keyword(s):  
Numerical Method ◽  
Fiber Length ◽  
Muscle Force ◽  
Isometric Force ◽  
Pennation Angle ◽  
Cross Sectional ◽  
Force Equation ◽  
Subject Specific ◽  
Maximum Isometric Force ◽  
Slack Length

Forces generated by muscle are transferred to bone via tendon. Since muscle force cannot be measured directly, computer modeling is a useful tool to enhance our understanding of normal and pathological movement. Hill-type muscle models have been used to estimate force based on information about a muscle’s architecture, activation and kinematics (Delp et al., 1995; Manal et al., 2002). Architectural parameters include optimal fiber length (lom), tendon slack length (lst), pennation angle (α), and maximum isometric force (Fmax). In addition, musculotendon length (lmt) and activation (a) are required inputs when estimating isometric muscle force (Equation I). Fm=f(lmt,lom,lst,Fmax,α,a)(1) Musculotendon length can be determined from MR images (Arnold et al., 2000), and activation recorded from EMGs (Manal, et al., 2002). Optimal fiber length and pennation angle can be measured experimentally (Murray, 2002), while Fmax can be estimated from the muscle’s physiologic cross-sectional area. Tendon slack length however cannot be measured readily, and therefore few estimates of lst can be found in the literature. In this paper we present a numerical method for estimating tendon slack from subject specific muscle parameters and musculotendon lengths. An advantage of this method is that it yields subject specific estimates of tendon slack length.

scholarly journals Architectural model for muscle growth during maturation

2021 ◽  
Author(s):  
Stefan Papenkort ◽  
Markus Böl ◽  
Tobias Siebert
Keyword(s):  
Model Development ◽  
Muscle Growth ◽  
Pennation Angle ◽  
Muscle Architecture ◽  
Data Sets ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Muscle Belly ◽  
Architectural Model ◽  
Relative Differences

AbstractMuscle architecture, which includes parameters like fascicle length, pennation angle, and physiological cross-sectional area, strongly influences skeletal muscles' mechanical properties. During maturation, the muscle architecture has to adapt to a growing organism. This study aimed to develop an architectural model capable of predicting the complete 3D fascicle architecture for primarily unipennate muscles of an arbitrary age, based on fascicle data for an initial age. For model development, we collected novel data on 3D muscle architecture of the rabbit (Oryctolagus cuniculus) M. plantaris of eight animals ranging in age from 29 to 106 days. Experimental results show that plantaris muscle belly length increases by 73%, whereas mean fascicle length and mean pennation angle increases by 39 and 14%, respectively. Those changes were incorporated into the model. In addition to the data collected for M. plantaris the predictions of the model were compared to existing literature data of rabbit M. soleus and M. gastrocnemius medialis. With an error of −1.0 ± 8.6% for relative differences in aponeurosis length, aponeurosis width, muscle height, and muscle mass, the model delivered good results matching interindividual differences. For future studies, the model could be utilized to generate realistic architectural data sets for simulation studies.

Chronic Adaptations of the Posterior Rotator Cuff in Professional Pitchers

2021 ◽  
pp. 036354652098868
Author(s):  
Stephen J. Thomas ◽  
Justin Cobb ◽  
Scott Sheridan ◽  
Joseph Rauch ◽  
Ryan W. Paul
Keyword(s):  
Soft Tissue ◽  
Rotator Cuff ◽  
Internal Rotation ◽  
External Rotation ◽  
Negative Relationship ◽  
Muscle Thickness ◽  
Pennation Angle ◽  
Muscle Architecture ◽  
Infraspinatus Muscle ◽  
Teres Minor

Background: Because of the large forces and high frequency of throwing, the upper extremity experiences repetitive stresses that lead to acute and chronic adaptations. While the importance of pennation angle and muscle thickness as predictors of muscle force production has been shown in other populations and other joints, there has been little research done that examines these variables in the shoulders of baseball players. Purpose: (1) To examine the chronic effect pitching has on the rotator cuff muscle architecture (pennation angle and muscle thickness) in healthy professional baseball pitchers, and (2) to examine the correlation between muscle architecture and clinical measures of strength and range of motion (ROM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-eight healthy professional pitchers were recruited during the 2019 spring training. Internal rotation (IR) and external rotation (ER) strength were measured with a handheld dynamometer and IR and ER ROM were measured with an inclinometer. A diagnostic ultrasound machine was utilized to capture images of humeral retroversion, as well as the pennation angle and muscle thickness of the infraspinatus and teres minor muscles. ImageJ software was used to quantify the pennation angle and muscle thickness. Results: There were no significant differences between the dominant and nondominant arms for ER or IR strength. Also, no pennation angle and muscle thickness differences were found between the dominant and nondominant arms. A weak positive relationship between infraspinatus muscle thickness (superficial and total) and ER strength ( P = .016, R = 0.287 and P = .009, R = 0.316) and a moderate negative relationship between soft tissue glenohumeral internal rotation deficit (GIRD) and the bilateral difference of the teres minor deep pennation angle ( R = −0.477, P = .008) were observed. No other significant relationships were noted. Conclusion: Our results are contrary to current literature as we expected to see a stronger dominant arm, with a larger pennation angle and greater muscle thickness. Interestingly, we found that ER strength was positively related to only the thickness of the infraspinatus muscle, and that soft tissue GIRD was positively related to only the side-to-side adaptation of the pennation angle within the deep portion of the teres minor. This suggests that when posterior shoulder tightness occurs, specifically the architecture of the teres minor muscle is involved. However, the organization to which these players belonged has a very extensive training protocol throughout the year that emphasizes bilateral training during a large majority of the exercises. Therefore, the results may not be generalizable to all professional players.

scholarly journals Correlation between age, muscle architecture, and muscle strength in children with Erb’s palsy

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Ahmed Saad Awad ◽  
Mostafa Soliman Ali ◽  
Mohamed Ismail Elassal
Keyword(s):  
Muscle Strength ◽  
Muscle Weakness ◽  
Muscle Thickness ◽  
Study Groups ◽  
Pennation Angle ◽  
Muscle Architecture ◽  
Active Movement ◽  
Significant Relation ◽  
Erb’S Palsy ◽  
Significant Difference

Abstract Background Muscle weakness is a widespread problem in children with Erb’s palsy as it can cause changes in muscle architecture parameters, which can be detected by ultrasonography. This study was conducted to determine the relation between age, muscle architecture, and muscle strength in children with Erb’s palsy. A total of 40 children with Erb’s palsy from both sexes aged 1–2.5 years were included in this study. Muscle thickness and pennation angle were measured by ultrasonography, and muscle strength was measured using the active movement scale. Results A significant relation was found between age, muscle thickness, pennation angle, and muscle strength (P < 0.05). Moreover, a significant difference was found in muscle architecture parameters during relaxation and contraction in both study groups and in each study group (P < 0.05). Conclusion Muscle weakness in children with Erb’s palsy has an effect on muscle architecture parameters, and these parameters also increase with age.

Effect of surface density and fiber length on the porosity and permeability of nonwoven flax reinforcement

2017 ◽  
Vol 88 (15) ◽  
pp. 1776-1787 ◽  
Author(s):  
Mohamed Habibi ◽  
Édu Ruiz ◽  
Gilbert Lebrun ◽  
Luc Laperrière
Keyword(s):  
Pore Size ◽  
Surface Density ◽  
Fiber Length ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Short Fiber ◽  
Fiber Volume ◽  
Fibrous Network ◽  
Porosity And Permeability ◽  
The Impact

This paper presents an experimental study and modeling of the influence of surface density and fiber length on the permeability of novel nonwoven flax fiber manufactured by the paper making process. Firstly, the relation between surface density, fiber lengths and pore size distribution measured with a porometer capillary instrument is reported in this study. The results show that higher surface density gives a denser fibrous network with a low porosity rate and longer fiber decreases the total number of fibers and increases the pore size for a given surface density. A liquid permeability study was then carried out to identify the impact of surface density, short fiber length and fiber volume fraction on in-plane impregnation of the reinforcement. Permeability was found to be inversely proportional to the reinforcement of surface density. In contrast, an increase of the fiber length increases the in-plane permeability of the reinforcement. Finally, a mathematical modeling is proposed to predict the permeability behavior of these innovative natural fiber webs.

scholarly journals The effects of eccentric training on hamstring muscle architecture

Kinesiology ◽  
2021 ◽  
Vol 53 (1) ◽  
pp. 141-153
Author(s):  
Murat Emirzeoğlu ◽  
Tüzün Fırat ◽  
Özlem Ülger
Keyword(s):  
Training Session ◽  
Muscle Thickness ◽  
Muscle Architecture ◽  
Eccentric Training ◽  
Hamstring Muscle ◽  
Cross Sectional ◽  
Functional Changes ◽  
Hamstring Injuries ◽  
Architectural Features ◽  
Hand Muscle

The architectural features of the hamstring muscle group are important to prevent injury or to reduce the risk of re-injury. Besides, eccentric training is often used in the rehabilitation of hamstring injuries. The aim of this systematic review was to examine the changes created by eccentric training on hamstring muscle architecture and to determine the minimal values of training duration and intensity for requiring functional changes. The research was conducted on the PubMed, Scopus, Web of Science, COCHRANE, CINAHL, and Pedro databases. Full-text studies examining the effect of eccentric training on at least one parameter of the hamstring muscle architecture were included in the review. Studies on cadavers and animals and studies involving different types of training combined with eccentric training were excluded. Twelve of the 7954 studies met the set criteria. According to the results, eccentric training undoubtedly increases fiber length. However, the pennation angle tends to decrease. On the other hand, muscle thickness and cross-sectional area tends to increase depending on the eccentric training. Although the frequency, number of sets and number of repetitions in sets were similar in the examined studies, muscle architecture changes were different. We think that eccentric training duration and the number of repetitions in total or per training session seem to have an impact on muscle architecture. In order to determine the minimal eccentric training program that can create these changes, quality research is needed to examine the duration, intensity and methods of eccentric training.

scholarly journals Fractional pulping of packaging board in high consistency drum pulping

TAPPI Journal ◽  
2017 ◽  
Vol 16 (02) ◽  
pp. 89-95
Author(s):  
HEIKKI UPOLA ◽  
ARI AMMALA ◽  
MIRJA ILLIKAINEN
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Fiber Length ◽  
Short Fiber ◽  
Strength Properties ◽  
Ash Content ◽  
Packaging Materials ◽  
Wet Strength ◽  
Fiber Fractions ◽  
High Consistency

A wide variety of packaging materials with different wetting rates and wet strength properties are used in old corrugated container (OCC) processing. The disintegration rates of the different grades also vary and enable the use of the fractional pulping concept where easily disintegrated material is removed at the early stages. In the present study, fractional drum pulping was studied by pulping (Pilot drum pulping) and fractionating (Tampella oscillating screen) a mixture of strong-grade kraftliner and weak-grade fluting at high consistency to determine if energy consumption could be reduced. The results showed that a 25% energy saving could be realized through fractional pulping and an even higher potential might be possible if pulping conditions are optimized. Average fiber length, fines content, and ash content in the separated fractions were analyzed. The separated short fiber fractions and long fiber fractions could be individually processed, thus decreasing the volumes in the unit processes on the OCC line.

Strength of short fiber reinforced polymers: Effect of fiber length distribution

2008 ◽  
Vol 29 (6) ◽  
pp. 644-648 ◽  
Author(s):  
Muratahan Aykol ◽  
Nihat Ali Isitman ◽  
Emre Firlar ◽  
Cevdet Kaynak
Keyword(s):  
Fiber Length ◽  
Length Distribution ◽  
Short Fiber ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Fiber Length Distribution

scholarly journals CORRELATION BETWEEN FIBER LENGTH, ULTRASTRUCTURE, AND THE LENGTH-TENSION RELATIONSHIP OF MAMMALIAN SMOOTH MUSCLE

1972 ◽  
Vol 52 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Peter H. Cooke ◽  
Fredric S. Fay
Keyword(s):  
Fiber Length ◽  
Ultrastructural Organization ◽  
Cross Sectional ◽  
Dense Bodies ◽  
Tentative Model ◽  
Functional Consequences ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Basic Features ◽  
Relationship Of

The length-tension relationship was determined for strips of guinea pig taenia coli and correlated with the length and ultrastructural organization of the component fibers. The mean fiber length in "stretched" strips (passive ≥ active tension) was 30% greater than that for fibers in "unstretched" strips (active &gt;&gt; passive tension). In stretched fibers the dense bodies and 100 A diameter myofilaments were consolidated into a mass near the center of fibers in cross-sectional profile. The thick myofilaments were segregated into the periphery of the fiber profiles. In unstretched fibers the dense bodies-100 A diameter filaments and the thick myofilaments were uniformly distributed throughout cross-sectional profiles. A tentative model is proposed to account for the change in fiber length and ultrastructural organization that accompanies stretch. The basic features of the model require the dense bodies to be linked together into a network by the 100 A diameter filaments. The functional consequences of stretching the fibers are discussed in relation to the model proposed for this network.

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