Gastrocnemius muscle specific force in boys and men

2008 ◽  
Vol 104 (2) ◽  
pp. 469-474 ◽  
Author(s):  
Christopher I. Morse ◽  
Keith Tolfrey ◽  
Jeanette M. Thom ◽  
Vasilios Vassilopoulos ◽  
Constantinos N. Maganaris ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Muscle Length ◽  
Tanner Stage ◽  
Surface Emg ◽  
Specific Force ◽  
Moment Arm ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Adult Men

The aim of this study was to assess whether the in vivo specific force and architectural characteristics of the lateral gastrocnemius (GL) muscle of early pubescent boys ( n = 11, age = 10.9 ± 0.3 yr, Tanner stage 2) differed from those of adult men ( n = 12, age = 25.3 ± 4.4 yr). Plantarflexor torque was 55% lower in the boys (77.4 ± 21.4 N·m) compared with the adults (175.6 ± 31.7 N·m, P < 0.01). Physiological cross-sectional area (PCSA), determined in vivo using ultrasonography and MRI, was 52% smaller in the boys ( P < 0.01). No difference was found in pennation angle, or in the ratio of fascicle length ( Lf) to muscle length between the boys and men. Moment arm length was 25% smaller in the boys ( P < 0.01). Antagonist coactivation, assessed using surface EMG on the dorsiflexors, was not different between the boys and men (11.8 ± 6.7% and 13.5 ± 5.8%, respectively). Surprisingly, GL force normalized to PCSA (specific force) was significantly higher (21%) in the boys than in the men (13.1 ± 2.0 vs. 15.9 ± 2.7 N/cm2, P < 0.05). This finding could not be explained by differences in moment arm length, muscle activation, or architecture, and other factors, such as tendinous characteristics and/or changes in moment arm length with contraction, may be held responsible. These observations warrant further investigation.

In vivo physiological cross-sectional area and specific force are reduced in the gastrocnemius of elderly men

2005 ◽  
Vol 99 (3) ◽  
pp. 1050-1055 ◽  
Author(s):  
Christopher I. Morse ◽  
Jeanette M. Thom ◽  
Neil D. Reeves ◽  
Karen M. Birch ◽  
Marco V. Narici
Keyword(s):  
Achilles Tendon ◽  
Voluntary Contraction ◽  
Pennation Angle ◽  
Specific Force ◽  
Plantar Flexor ◽  
Moment Arm ◽  
Plantar Flexors ◽  
Elderly Men ◽  
Cross Sectional

Sarcopenia and muscle weakness are well-known consequences of aging. The aim of the present study was to ascertain whether a decrease in fascicle force (Ff) could be accounted for entirely by muscle atrophy. In vivo physiological cross-sectional area (PCSA) and specific force (Ff/PCSA) of the lateral head of the gastrocnemius (GL) muscle were assessed in a group of elderly men [EM, aged 73.8 yr (SD 3.5), height 173.4 cm (SD 4.4), weight 78.4 kg (SD 8.3); means (SD)] and for comparison in a group of young men [YM, aged 25.3 yr (SD 4.4), height 176.4 cm (SD 7.7), weight 79.1 kg (SD 11.9)]. GL muscle volume (Vol) and Achilles tendon moment arm length were evaluated using magnetic resonance imaging. Pennation angle and fiber fascicle length (Lf) were measured using B-mode ultrasonography during isometric maximum voluntary contraction of the plantar flexors. PCSA was estimated as Vol/Lf. GL Ff was calculated by dividing Achilles tendon force by the cosine of θ, during the interpolation of a supramaximal doublet, and accounting for antagonist activation level (assessed using EMG), Achilles tendon moment arm length, and the relative PCSA of the GL within the plantar flexor group. Voluntary activation of the plantar flexors was lower in the EM than in the YM (86 vs. 98%, respectively, P < 0.05). Compared with the YM, plantar flexor maximal voluntary contraction torque and Ff of the EM were lower by 47 and 40%, respectively ( P < 0.01). Both Vol and PCSA were smaller in the EM by 28% ( P < 0.01) and 16% ( P < 0.05), respectively. Also, pennation angle was 12% smaller in the EM, whereas there was no significant difference in Lf between the YM and EM. After accounting for differences in agonists and antagonists activation, the Ff/PCSA of the EM was 30% lower than that of the YM ( P < 0.01). These findings demonstrate that the loss of muscle strength with aging may be explained not only by a reduction in voluntary drive to the muscle, but mostly by a decrease in intrinsic muscle force. This phenomenon may possibly be due to a reduction in single-fiber specific tension.

scholarly journals Three-dimensional geometrical changes of the human tibialis anterior muscle and its central aponeurosis measured with three-dimensional ultrasound during isometric contractions

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2260 ◽  
Author(s):  
Brent J. Raiteri ◽  
Andrew G. Cresswell ◽  
Glen A. Lichtwark
Keyword(s):  
Three Dimensional ◽  
Muscle Length ◽  
Pennation Angle ◽  
Human Muscle ◽  
Muscle Fibres ◽  
Isometric Contractions ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Shape Changes

Background.Muscles not only shorten during contraction to perform mechanical work, but they also bulge radially because of the isovolumetric constraint on muscle fibres. Muscle bulging may have important implications for muscle performance, however quantifying three-dimensional (3D) muscle shape changes in human muscle is problematic because of difficulties with sustaining contractions for the duration of anin vivoscan. Although two-dimensional ultrasound imaging is useful for measuring local muscle deformations, assumptions must be made about global muscle shape changes, which could lead to errors in fully understanding the mechanical behaviour of muscle and its surrounding connective tissues, such as aponeurosis. Therefore, the aims of this investigation were (a) to determine the intra-session reliability of a novel 3D ultrasound (3DUS) imaging method for measuringin vivohuman muscle and aponeurosis deformations and (b) to examine how contraction intensity influencesin vivohuman muscle and aponeurosis strains during isometric contractions.Methods.Participants (n= 12) were seated in a reclined position with their left knee extended and ankle at 90° and performed isometric dorsiflexion contractions up to 50% of maximal voluntary contraction. 3DUS scans of the tibialis anterior (TA) muscle belly were performed during the contractions and at rest to assess muscle volume, muscle length, muscle cross-sectional area, muscle thickness and width, fascicle length and pennation angle, and central aponeurosis width and length. The 3DUS scan involved synchronous B-mode ultrasound imaging and 3D motion capture of the position and orientation of the ultrasound transducer, while successive cross-sectional slices were captured by sweeping the transducer along the muscle.Results.3DUS was shown to be highly reliable across measures of muscle volume, muscle length, fascicle length and central aponeurosis length (ICC ≥ 0.98, CV < 1%). The TA remained isovolumetric across contraction conditions and progressively shortened along its line of action as contraction intensity increased. This caused the muscle to bulge centrally, predominantly in thickness, while muscle fascicles shortened and pennation angle increased as a function of contraction intensity. This resulted in central aponeurosis strains in both the transverse and longitudinal directions increasing with contraction intensity.Discussion.3DUS is a reliable and viable method for quantifying multidirectional muscle and aponeurosis strains during isometric contractions within the same session. Contracting muscle fibres do work in directions along and orthogonal to the muscle’s line of action and central aponeurosis length and width appear to be a function of muscle fascicle shortening and transverse expansion of the muscle fibres, which is dependent on contraction intensity. How factors other than muscle force change the elastic mechanical behaviour of the aponeurosis requires further investigation.

scholarly journals Three-dimensional architecture of the whole human soleus muscle in vivo

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4610 ◽  
Author(s):  
Bart Bolsterlee ◽  
Taija Finni ◽  
Arkiev D’Souza ◽  
Junya Eguchi ◽  
Elizabeth C. Clarke ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Diffusion Tensor ◽  
Three Dimensional ◽  
Muscle Length ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Quantitative Measurements ◽  
Muscle Fascicle ◽  
Total Muscle

Background Most data on the architecture of the human soleus muscle have been obtained from cadaveric dissection or two-dimensional ultrasound imaging. We present the first comprehensive, quantitative study on the three-dimensional anatomy of the human soleus muscle in vivo using diffusion tensor imaging (DTI) techniques. Methods We report three-dimensional fascicle lengths, pennation angles, fascicle curvatures, physiological cross-sectional areas and volumes in four compartments of the soleus at ankle joint angles of 69 ± 12° (plantarflexion, short muscle length; average ± SD across subjects) and 108 ± 7° (dorsiflexion, long muscle length) of six healthy young adults. Microdissection and three-dimensional digitisation on two cadaveric muscles corroborated the compartmentalised structure of the soleus, and confirmed the validity of DTI-based muscle fascicle reconstructions. Results The posterior compartments of the soleus comprised 80 ± 5% of the total muscle volume (356 ± 58 cm3). At the short muscle length, the average fascicle length, pennation angle and curvature was 37 ± 8 mm, 31 ± 3° and 17 ± 4 /m, respectively. We did not find differences in fascicle lengths between compartments. However, pennation angles were on average 12° larger (p < 0.01) in the posterior compartments than in the anterior compartments. For every centimetre that the muscle-tendon unit lengthened, fascicle lengths increased by 3.7 ± 0.8 mm, pennation angles decreased by −3.2 ± 0.9° and curvatures decreased by −2.7 ± 0.8 /m. Fascicles in the posterior compartments rotated almost twice as much as in the anterior compartments during passive lengthening. Discussion The homogeneity in fascicle lengths and inhomogeneity in pennation angles of the soleus may indicate a functionally different role for the anterior and posterior compartments. The data and techniques presented here demonstrate how DTI can be used to obtain detailed, quantitative measurements of the anatomy of complex skeletal muscles in living humans.

scholarly journals Specific force of the vastus lateralis in adults with achondroplasia

2018 ◽  
Vol 124 (3) ◽  
pp. 696-703 ◽  
Author(s):  
David T. Sims ◽  
Gladys L. Onambélé-Pearson ◽  
Adrian Burden ◽  
Carl Payton ◽  
Christopher I. Morse
Keyword(s):  
Vastus Lateralis ◽  
Force Production ◽  
Limb Length ◽  
Muscle Size ◽  
Knee Extensors ◽  
Specific Force ◽  
Moment Arm ◽  
Cross Sectional ◽  
Volume Activation

Achondroplasia is a clinical condition defined by shorter stature and disproportionate limb length. Force production in able-bodied individuals (controls) is proportional to muscle size, but given the disproportionate nature of achondroplasia, normalizing to anatomical cross-sectional area (ACSA) is inappropriate. The aim of this study was to assess specific force of the vastus lateralis (VL) in 10 adults with achondroplasia (22 ± 3 yr) and 18 sex-matched controls (22 ± 2 yr). Isometric torque (iMVCτ) of the dominant knee extensors (KE) and in vivo measures of VL muscle architecture, volume, activation, and patella tendon moment arm were used to calculate VL physiological CSA (PCSA), fascicle force, and specific force in both groups. Achondroplasic muscle volume was 53% smaller than controls (284 ± 36 vs. 604 ± 102 cm3, P < 0.001). KE iMVCτ was 63% lower in achondroplasia compared with controls (95 ± 24 vs. 256 ± 47 N⋅m, P < 0.001). Activation and moment arm length were similar between groups ( P > 0.05), but coactivation of bicep femoris of achondroplasic subjects was 70% more than controls (43 ± 20 vs. 13 ± 5%, P < 0.001). Achondroplasic subjects had 58% less PCSA (43 ± 10 vs. 74.7 ± 14 cm2, P < 0.001), 29% lower fascicle force (702 ± 235 vs. 1704 ± 303 N, P < 0.001), and 29% lower specific force than control subjects (17 ± 6 vs. 24 ± 6 N⋅cm−2, P = 0.012). The smaller VL specific force in achondroplasia may be attributed to infiltration of fat and connective tissue, rather than to any difference in myofilament function. NEW & NOTEWORTHY The novel observation of this study was the measurement of normalized force production in a group of individuals with disproportionate limb length-to-torso ratios.

Muscle Quality, Architecture, and Activation in Cachectic Patients with Rheumatoid Arthritis

2009 ◽  
Vol 37 (2) ◽  
pp. 282-284 ◽  
Author(s):  
VERENA MATSCHKE ◽  
PETER MURPHY ◽  
ANDREW B. LEMMEY ◽  
PETER J. MADDISON ◽  
JEANETTE M. THOM
Keyword(s):  
Rheumatoid Arthritis ◽  
Physical Function ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Pennation Angle ◽  
Voluntary Activation ◽  
Muscle Quality ◽  
Specific Force ◽  
Fascicle Length ◽  
Cross Sectional

Objective. To explore muscle-specific force (force per physiological cross-sectional area, or PCSA) and muscle activation in cachectic patients with rheumatoid arthritis (RA).Methods. In 14 muscle-wasted patients with RA and age and sex matched healthy controls, vastus lateralis (VL) force and voluntary activation capacity were assessed during maximal isometric contractions with electromyography and superimposed electrical stimulations. VL PCSA was determined from ultrasound measures of fiber fascicle length (Lf), pennation angle, and volume, together with assessments of body composition by dual energy x-ray absorptiometry and objective physical function.Results. Although patients with RA had reduced physical function, lower muscle mass, and VL volume relative to controls, there were no differences in muscle-specific force and activation. PCSA, force, and pennation angle tended to be lower in RA, with no differences in Lf.Conclusion. Muscle-specific force and activation are not compromised and thus are unlikely to contribute to reduced function in cachectic patients with RA.

In vivo loads on airway smooth muscle: the role of noncontractile airway structures

1992 ◽  
Vol 70 (4) ◽  
pp. 602-606 ◽  
Author(s):  
Philip Robinson ◽  
Mitsushi Okazawa ◽  
Tony Bai ◽  
Peter Paré
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Muscle Activation ◽  
Muscle Length ◽  
Tracheal Cartilage ◽  
Elastic Load ◽  
Muscle Shortening ◽  
Trachealis Muscle

The degree of airway smooth muscle contraction and shortening that occurs in vivo is modified by many factors, including those that influence the degree of muscle activation, the resting muscle length, and the loads against which the muscle contracts. Canine trachealis muscle will shorten up to 70% of starting length from optimal length in vitro but will only shorten by around 30% in vivo. This limitation of shortening may be a result of the muscle shortening against an elastic load such as could be applied by tracheal cartilage. Limitation of airway smooth muscle shortening in smaller airways may be the result of contraction against an elastic load, such as could be applied by lung parenchymal recoil. Measurement of the elastic loads applied by the tracheal cartilage to the trachealis muscle and by lung parenchymal recoil to smooth muscle of smaller airways were performed in canine preparations. In both experiments the calculated elastic loads applied by the cartilage and the parenchymal recoil explained in part the limitation of maximal active shortening and airway narrowing observed. We conclude that the elastic loads provided by surrounding structures are important in determining the degree of airway smooth muscle shortening and the resultant airway narrowing.Key words: elastic loads, tracheal cartilage, airway smooth muscle shortening.

Motor unit firing rates during isometric voluntary contractions performed at different muscle lengths

2004 ◽  
Vol 82 (8-9) ◽  
pp. 769-776 ◽  
Author(s):  
Alejandro Del Valle ◽  
Christine K Thomas
Keyword(s):  
Motor Unit ◽  
Muscle Activation ◽  
Muscle Length ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Force Frequency ◽  
Triceps Brachii ◽  
Firing Rates ◽  
Motor Unit Firing ◽  
Voluntary Contractions

Firing rates of motor units and surface EMG were measured from the triceps brachii muscles of able-bodied subjects during brief submaximal and maximal isometric voluntary contractions made at 5 elbow joint angles that covered the entire physiological range of muscle lengths. Muscle activation at the longest, midlength, and shortest muscle lengths, measured by twitch occlusion, averaged 98%, 97%, and 93% respectively, with each subject able to achieve complete activation during some contractions. As expected, the strongest contractions were recorded at 90° of elbow flexion. Mean motor unit firing rates and surface EMG increased with contraction intensity at each muscle length. For any given absolute contraction intensity, motor unit firing rates varied when muscle length was changed. However, mean motor unit firing rates were independent of muscle length when contractions were compared with the intensity of the maximal voluntary contraction (MVC) achieved at each joint angle.Key words: muscle activation, length–tension relationships, force–frequency relationships.

scholarly journals What makes long-term resistance-trained individuals so strong? A comparison of skeletal muscle morphology, architecture, and joint mechanics

2020 ◽  
Vol 128 (4) ◽  
pp. 1000-1011 ◽  
Author(s):  
Thomas M. Maden-Wilkinson ◽  
Thomas G. Balshaw ◽  
Garry J. Massey ◽  
Jonathan P. Folland
Keyword(s):  
Skeletal Muscle ◽  
Muscle Volume ◽  
Sectional Area ◽  
Joint Mechanics ◽  
Moment Arm ◽  
Trained Group ◽  
Patella Tendon ◽  
Fascicle Length ◽  
Cross Sectional

Here we demonstrate that the larger muscle strength (+60%) of a long-term (4+ yr) resistance-trained group compared with untrained controls was due to their similarly larger muscle volume (+56%), primarily due to a larger physiological cross-sectional area and modest differences in fascicle length, as well as modest differences in maximum voluntary specific tension and patella tendon moment arm. In addition, the present study refutes the possibility of regional hypertrophy, despite large differences in muscle volume.

Enhanced myogenic activation in skeletal muscle arterioles from spontaneously hypertensive rats

1993 ◽  
Vol 265 (6) ◽  
pp. H1847-H1855 ◽  
Author(s):  
J. C. Falcone ◽  
H. J. Granger ◽  
G. A. Meininger
Keyword(s):  
Venous Pressure ◽  
Muscle Length ◽  
Vascular Wall ◽  
Intraluminal Pressure ◽  
Active Tension ◽  
Hypertensive Rats ◽  
Cross Sectional ◽  
Wall Area ◽  
Myogenic Responses

The purpose of this study was to determine whether the vascular myogenic response is enhanced in hypertension. Experiments were conducted in the intact cremaster muscle microcirculation as well as in isolated arterioles of hypertensive (SHR) and normotensive (WKY) rats. Increasing venous pressure in vivo by approximately 5 mmHg had no effect on normotensive first- (1A) or third-order arteriolar (3A) diameters; in contrast, hypertensive 1A diameter decreased 4% (89 +/- 2 to 85 +/- 3 microns) with an 8% decrease in 3A (24 +/- 2 to 22 +/- 2 microns). To further examine this enhanced constriction to elevated intravascular pressure in SHR, diameter was monitored in isolated 1A during step increases and decreases in intraluminal pressure. Normotensive arterioles displayed myogenic responses between pressures of 50 and 170 cmH2O; in contrast, hypertensive arterioles demonstrated myogenic responses over an extended pressure range (50–210 cmH2O). In addition, the change in diameter for each step change in pressure was greater in the arterioles from SHR, indicating an increased myogenic responsiveness. The myogenic reactions were unaffected by alpha-receptor blockade with phentolamine (10(-6) M), indicating that adrenergic hypersensitivity was not involved in the enhanced response to stretch. Morphometric analysis of the vascular wall revealed no differences in wall thickness, cross-sectional wall area, or wall-to-lumen ratio between normotensive and hypertensive rats. The length-tension relationships for normotensive and hypertensive rats demonstrated that peak active tension occurred at nearly the same vascular smooth muscle length. In addition, SHR arterioles were capable of maintaining higher levels of active tension that WKY arterioles, indicating an altered length-tension curve in chronic arterial hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Rate of Muscle Activation in Power-and Endurance-Trained Boys

2011 ◽  
Vol 6 (1) ◽  
pp. 94-105 ◽  
Author(s):  
Cameron Mitchell ◽  
Rotem Cohen ◽  
Raffy Dotan ◽  
David Gabriel ◽  
Panagiota Klentrou ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Peak Torque ◽  
Surface Emg ◽  
Knee Extension ◽  
Endurance Athletes ◽  
Group Differences ◽  
Electromechanical Delay ◽  
Cross Sectional ◽  
Isometric Knee Extension ◽  
Muscle Cross Sectional Area

Previous studies in adults have demonstrated power athletes as having greater muscle force and muscle activation than nonathletes. Findings on endurance athletes are scarce and inconsistent. No comparable data on child athletes exist.Purpose:This study compared peak torque (Tq), peak rate of torque development (RTD), and rate of muscle activation (EMG rise, Q30), in isometric knee extension (KE) and fexion (KF), in pre- and early-pubertal power- and endurance-trained boys vs minimally active nonathletes.Methods:Nine gymnasts, 12 swimmers, and 18 nonathletes (7–12 y), performed fast, maximal isometric KE and KF. Values for Tq, RTD, electromechanical delay (EMD), and Q30 were calculated from averaged torque and surface EMG traces.Results:No group differences were observed in Tq, normalized for muscle cross-sectional area. The Tq-normalized KE RTD was highest in power athletes (6.2 ± 1.9, 4.7 ± 1.2, 5.0 ± 1.5 N·m·s–1, for power, endurance, and nonathletes, respectively), whereas no group differences were observed for KF. The KE Q30 was significantly greater in power athletes, both in absolute terms and relative to peak EMG amplitude (9.8 ± 7.0, 5.9 ± 4.2, 4.4 ± 2.2 mV·ms and 1.7 ± 0.8, 1.1 ± 0.6, 0.9 ± 0.5 (mV·ms)/(mV) for power, endurance, and nonathletes, respectively), with no group differences in KF. The KE EMD tended to be shorter (P = .07) in power athletes during KE (71.0 ± 24.1, 87.8 ± 18.0, 88.4 ± 27.8 ms, for power, endurance, and nonathletes), with no group differences in KF.Conclusions:Pre- and early-pubertal power athletes have enhanced rate of muscle activation in specifically trained muscles compared with controls or endurance athletes, suggesting that specific training can result in muscle activation-pattern changes before the onset of puberty.

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