scholarly journals The Effect of Multidirectional Loading on Contractions of the M. Medial Gastrocnemius

2021 ◽  
Vol 11 ◽  
Author(s):  
David S. Ryan ◽  
Norman Stutzig ◽  
Andreas Helmer ◽  
Tobias Siebert ◽  
James M. Wakeling
Keyword(s):  
Muscle Force ◽  
Force Production ◽  
Muscle Length ◽  
Muscle Thickness ◽  
Medial Gastrocnemius ◽  
Transverse Loading ◽  
Two Factors ◽  
Muscle Loading ◽  
Force Reduction ◽  
Multidirectional Loading

Research has shown that compression of muscle can lead to a change in muscle force. Most studies show compression to lead to a reduction in muscle force, although recent research has shown that increases are also possible. Based on methodological differences in the loading design between studies, it seems that muscle length and the direction of transverse loading influence the effect of muscle compression on force production. Thus, in our current study we implement these two factors to influence the effects of muscle loading. In contrast to long resting length of the medial gastrocnemius (MG) in most studies, we use a shorter MG resting length by having participant seated with their knees at a 90° angle. Where previous studies have used unidirectional loads to compress the MG, in this study we applied a multidirectional load using a sling setup. Multidirectional loading using a sling setup has been shown to cause muscle force reductions in previous research. As a result of our choices in experimental design we observed changes in the effects of muscle loading compared to previous research. In the present study we observed no changes in muscle force due to muscle loading. Muscle thickness and pennation angle showed minor but significant increases during contraction. However, no significant changes occurred between unloaded and loaded trials. Fascicle thickness and length showed different patterns of change compared to previous research. We show that muscle loading does not result in force reduction in all situations and is possibly linked to differences in muscle architecture and muscle length.

MUSCLE BULGING REDUCES MUSCLE FORCE AND LIMITS THE MAXIMAL EFFECTIVE MUSCLE SIZE

2006 ◽  
Vol 06 (03) ◽  
pp. 229-239 ◽  
Author(s):  
KARL DAGGFELDT
Keyword(s):  
Muscle Force ◽  
Muscle Length ◽  
Biomechanical Model ◽  
Muscle Performance ◽  
Muscle Size ◽  
Intramuscular Pressure ◽  
Shortening Velocity ◽  
Muscle Shortening ◽  
Force Reduction ◽  
Total Muscle

A biomechanical model was generated in order to investigate the possible mechanisms behind reductions in muscle performance due to muscle bulging. It was shown that the proportion of fiber force contributing to the total muscle force is reduced with fiber bulging and that the cause of this reduction is due to the intramuscular pressure (IMP) created by the bulging fibers. Moreover, it was established that the amount of IMP generated muscle force reduction is determined by the extent to which muscle thickening restricts muscle fibers from shortening, thereby limiting their power contribution. It was shown that bulging can set a limit to the maximal size a muscle can take without losing force and power producing capability. Possible effects, due to bulging, on maximal muscle force in relation to both muscle length and muscle shortening velocity were also demonstrated by the model.

In vivo determination of fascicle curvature in contracting human skeletal muscles

2002 ◽  
Vol 92 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Tadashi Muramatsu ◽  
Tetsuro Muraoka ◽  
Yasuo Kawakami ◽  
Akira Shibayama ◽  
Tetsuo Fukunaga
Keyword(s):  
Maximum Voluntary Contraction ◽  
Muscle Length ◽  
Muscle Thickness ◽  
Voluntary Contraction ◽  
Pennation Angle ◽  
Medial Gastrocnemius ◽  
Fascicle Length ◽  
Fascicle Curvature

Fascicle curvature of human medial gastrocnemius muscle (MG) was determined in vivo by ultrasonography during isometric contractions at three (distal, central, and proximal) locations ( n = 7) and at three ankle angles ( n = 7). The curvature significantly ( P < 0.05) increased from rest to maximum voluntary contraction (MVC) (0.4–5.2 m−1). In addition, the curvature at MVC became larger in the order dorsiflexed, neutral, plantar flexed ( P < 0.05). Thus both contraction levels and muscle length affected the curvature. Intramuscular differences in neither the curvature nor the fascicle length were found. The direction of curving was consistent along the muscle: fascicles were concave in the proximal side. Fascicle length estimated from the pennation angle and muscle thickness, under the assumption that the fascicle was straight, was underestimated by ∼6%. In addition, the curvature was significantly correlated to pennation angle and muscle thickness. These findings are particularly important for understanding the mechanical functions of human skeletal muscle in vivo.

scholarly journals Age-related reductions in the number of serial sarcomeres contribute to shorter fascicle lengths but not elevated passive tension

2021 ◽  
Author(s):  
Geoffrey A. Power ◽  
Sean Crooks ◽  
Jared R. Fletcher ◽  
Brian R. Macintosh ◽  
Walter Herzog
Keyword(s):  
Force Production ◽  
Muscle Length ◽  
Medial Gastrocnemius ◽  
Slight Reduction ◽  
Passive Force ◽  
Fascicle Length ◽  
Age Related ◽  
Absolute Length ◽  
Old Rats ◽  
Length Changes

We investigated age-related changes to fascicle length (FL), sarcomere length (SL), and serial sarcomere number (SSN), and how this affects passive force. Following mechanical testing to determine passive force, the medial gastrocnemius muscle of young (n=9) and old (n=8) Fisher 344BN hybrid rats was chemically fixed at the optimal muscle length for force production; individual fascicles were dissected for length measurement, and laser diffraction was used to assess SL. Old rats had ∼14% shorter FL than young, which was driven by a ∼10% reduction in SSN, with no difference in SL (∼4%). Passive force was greater in the old compared to young rats at long muscle lengths. Shorter FL and reduced SSN in the old rats could not entirely explain increased passive forces for absolute length changes, owing to a slight reduction in SL in old, resulting in similar SL at long muscle lengths.

Does Raising Morning Rectal Temperature to Evening Levels Offset the Diurnal Variation in Muscle Force Production?

2013 ◽  
Vol 30 (4) ◽  
pp. 486-501 ◽  
Author(s):  
Ben J. Edwards ◽  
Samuel A. Pullinger ◽  
Jonathan W. Kerry ◽  
William R. Robinson ◽  
Tom P. Reilly ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Rectal Temperature ◽  
Muscle Force ◽  
Force Production ◽  
Muscle Force Production

Electromyographic and ultrasonographic evaluation of neuromuscular electrical stimulation training on the equine rectus abdominis muscle

2020 ◽  
Vol 16 (2) ◽  
pp. 87-100
Author(s):  
T. Hernández-Fernández ◽  
L. Gutiérrez-Cepeda ◽  
J. López-Sanromán ◽  
G. Manso-Díaz ◽  
R. Cediel
Keyword(s):  
Electrical Stimulation ◽  
Muscle Force ◽  
Neuromuscular Electrical Stimulation ◽  
Muscle Thickness ◽  
Muscular Contraction ◽  
Rectus Abdominis ◽  
Wilcoxon Test ◽  
Median Frequency ◽  
Rectus Abdominis Muscle ◽  
Test Analysis

The current study aimed to determine the effects of neuromuscular electrical stimulation (NMES) on equine rectus abdominis using surface electromyography (sEMG) and ultrasonographic muscle thickness evaluation. Five horses were trained with NMES for 12 weeks; muscle thickness and sEMG evaluations were obtained before and after the training period. Three different tests were carried out for sEMG evaluations: Test A tried to elicit a voluntary maximal isometric contraction (VMIC); Test B used NMES to elicit a muscular contraction; and Test C used 1 ms repetitive electrical impulses to elicit a series of M-waves. Muscle strength was evaluated from the root mean square (RMS; Tests A and B) and peak to peak (PP; Test C) values obtained from the sEMG data. Measures related to amplitude (RMSa; RMSm; RMSa; PP) were normalised with their pre-training values for every muscle prior to statistical analysis, leading to values as a proportion of the initial value. The evaluation of muscle fatigue was performed using a Fourier test analysis of the frequency range, obtaining the median frequency (MF) for all tests. Muscle thickness (MT) was measured by ultrasound of left and right sides of the rectus abdominis. Data were analysed using non parametric test of Wilcoxon (Test A RMSa; Test A RMSm; Test B RMSa; Test B RMSm; Test C PP; MT; P<0.05) and t-test (Test A MF; Test B MF; Test C MF; P<0.05). Statistical differences were observed between baseline and trained horses. Muscle force increase following NMES training in Test B (RMSa 2.50±0.69; RMSm 2.59±0.76) and Test C (PP 5.20±1.76). Fatigue of the rectus abdominis decreased in Test A (168.33±55.19 vs 232.63±44.15 Hz) and Test C MF (187.93±20.76 vs 236.98±52.39 Hz), but not in Test B (363.98±45.48 vs 327.95±50.84 Hz). The difference in muscle thickness between the two groups was not significant (10.96±0.64; 11.78±0.79 mm). The results suggest that NMES training could be used as an effective method to increase muscle force and fatigue resistance of the rectus abdominis muscle in the horse.

The effects of pH on force and stiffness development in mouse muscles

1987 ◽  
Vol 65 (8) ◽  
pp. 1798-1801 ◽  
Author(s):  
J. M. Renaud ◽  
R. B. Stein ◽  
T. Gordon
Keyword(s):  
High Frequency ◽  
Small Amplitude ◽  
Force Production ◽  
Muscle Length ◽  
Low Ph ◽  
Muscle Stiffness ◽  
Average Force ◽  
Cross Bridge ◽  
Effects Of Ph ◽  
Cross Bridges

Changes in force and stiffness during contractions of mouse extensor digitorum longus and soleus muscles were measured over a range of extracellular pH from 6.4 to 7.4. Muscle stiffness was measured using small amplitude (<0.1% of muscle length), high frequency (1.5 kHz) oscillations in length. Twitch force was not significantly affected by changes in pH, but the peak force during repetitive stimulation (2, 3, and 20 pulses) was decreased significantly as the pH was reduced. Changes in muscle stiffness with pH were in the same direction, but smaller in extent. If the number of attached cross-bridges in the muscle can be determined from the measurement of small amplitude, high frequency muscle stiffness, then these findings suggest that (a) the number of cross-bridges between thick and thin filaments declines in low pH and (b) the average force per cross-bridge also declines in low pH. The decline in force per cross-bridge could arise from a reduction in the ability of cross-bridges to generate force during their state of active force production and (or) in an increased percentage of bonds in a low force, "rigor" state.

Selected Contribution: Effect of chronic passive length change on airway smooth muscle length-tension relationship

2001 ◽  
Vol 90 (2) ◽  
pp. 734-740 ◽  
Author(s):  
Lu Wang ◽  
Peter D. Paré ◽  
Chun Y. Seow
Keyword(s):  
Smooth Muscle ◽  
Force Production ◽  
Muscle Length ◽  
Electrical Field Stimulation ◽  
Length Change ◽  
Electrical Field ◽  
Optimal Length ◽  
Active Length ◽  
Reference Length ◽  
Relationship Of

The ability of rabbit trachealis to undergo plastic adaptation to chronic shortening or lengthening was assessed by setting the muscle preparations at three lengths for 24 h in relaxed state: a reference length in which applied force was ∼1–2% of maximal active force (Po) and lengths considerably shorter and longer than the reference. Passive and active length-tension ( L-T) curves for the preparations were then obtained by electrical field stimulation at progressively increasing muscle length. Classically shaped L-T curves were obtained with a distinct optimal length ( L o) at which Podeveloped; however, both the active and passive L-T curves were shifted, whereas Po remained unchanged. L o was 72% and 148% that of the reference preparations for the passively shortened and lengthened muscles, respectively. The results suggest that chronic narrowing of the airways could induce a shift in the L-T relationship of smooth muscle, resulting in a maintained potential for maximal force production.

scholarly journals Reports of the length dependence of fatigue are greatly exaggerated

2006 ◽  
Vol 101 (1) ◽  
pp. 23-29 ◽  
Author(s):  
M. B. MacNaughton ◽  
B. R. MacIntosh
Keyword(s):  
Muscle Length ◽  
Repetitive Stimulation ◽  
Double Pulse ◽  
Medial Gastrocnemius ◽  
Passive Force ◽  
Active Force ◽  
Rightward Shift ◽  
Length Dependence ◽  
Force Depression ◽  
In Series

Relative force depression associated with muscle fatigue is reported to be greater when assessed at short vs. long muscle lengths. This appears to be due to a rightward shift in the force-length relationship. This rightward shift may be caused by stretch of in-series structures, making sarcomere lengths shorter at any given muscle length. Submaximal force-length relationships (twitch, double pulse, 50 Hz) were evaluated before and after repetitive contractions (50 Hz, 300 ms, 1/s) in an in situ preparation of the rat medial gastrocnemius muscle. In some experiments, fascicle lengths were measured with sonomicrometry. Before repetitive stimulation, fascicle lengths were 11.3 ± 0.8, 12.8 ± 0.9, and 14.4 ± 1.2 mm at lengths corresponding to −3.6, 0, and 3.6 mm where 0 is a reference length that corresponds with maximal active force for double-pulse stimulation. After repetitive stimulation, there was no change in fascicle lengths; these lengths were 11.4 ± 0.8, 12.6 ± 0.9, and 14.2 ± 1.2 mm. The length dependence of fatigue was, therefore, not due to a stretch of in-series structures. Interestingly, the rightward shift that was evident when active force was calculated in the traditional way (subtraction of the passive force measured before contraction) was not seen when active force was calculated by subtracting the passive force that was associated with the fascicle length reached at the peak of the contraction. This calculation is based on the assumption that passive force decreases as the fascicles shorten during a fixed-end contraction. This alternative calculation revealed similar postfatigue absolute active force depression at all lengths. In relative terms, a length dependence of fatigue was still evident, but this was greatly diminished compared with that observed when active force was calculated with the traditional method.

scholarly journals Muscle Thickness and Echo Intensity by Ultrasonography and Cognitive and Physical Dimensions in Older Adults

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1471
Author(s):  
Alvaro Mateos-Angulo ◽  
Alejandro Galán-Mercant ◽  
Antonio Ignacio Cuesta-Vargas
Keyword(s):  
Older Adults ◽  
Older People ◽  
Physical Performance ◽  
Functional Capacity ◽  
Biceps Brachii ◽  
Handgrip Strength ◽  
Muscle Thickness ◽  
Medial Gastrocnemius ◽  
Echo Intensity ◽  
Physical Dimensions

The purpose of the present study was to investigate the associations between muscle thickness and echo intensity with cognitive and physical dimensions like functional capacity measured in older people. This cross-sectional study involved 20 older adults (15 women and 5 men, mean age ± SD: 85 ± 7 years, body mass index: 25 ± 3 kg/m2) from a geriatric centre in Malaga (Spain). Anthropometric measurements, cognitive assessment with Pfeiffer Short Portable Mental Status Questionnaire and Motor Memory test, Physical Performance with Short Physical Performance Battery, and muscle strength were tested. Additionally, using B-mode ultrasonography, images of wrist flexors, biceps brachii, rectus femoris, vastus lateralis, medial gastrocnemius, and tibialis anterior were captured, and muscle thickness and echo intensity variables were extracted. An association between muscle parameters assessed by ultrasonography and cognitive and physical dimensions were found in older people. Echo intensity was the best predictor in a set of regression models with different muscle parameters and a battery of cognitive and physical tests in older people. Echo intensity adjusted by handgrip strength could be a low cost and ambulatory index and an indirect and reversible indicator of functional capacity.

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