In vivo dynamics of human medial gastrocnemius muscle-tendon complex during stretch-shortening cycle exercise

2000 ◽  
Vol 170 (2) ◽  
pp. 127-135 ◽  
Author(s):  
K. Kubo ◽  
H. Kanehisa ◽  
D. Takeshita ◽  
Y. Kawakami ◽  
S. Fukashiro ◽  
...  
Keyword(s):  
Gastrocnemius Muscle ◽  
Medial Gastrocnemius ◽  
Cycle Exercise ◽  
Stretch Shortening Cycle ◽  
Medial Gastrocnemius Muscle

Can in Vivo Medial Gastrocnemius Muscle–Tendon Unit Lengths be Reliably Estimated by Two Ultrasonography Methods? A Within-Session Analysis

2018 ◽  
Vol 44 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Francesco Cenni ◽  
Simon-Henri Schless ◽  
Lynn Bar-On ◽  
Guy Molenaers ◽  
Anja Van Campenhout ◽  
...  
Keyword(s):  
Gastrocnemius Muscle ◽  
Medial Gastrocnemius ◽  
Session Analysis ◽  
Medial Gastrocnemius Muscle

In vivo IIX and IIB fiber recruitment in gastrocnemius muscle of the rat is compartment related

1996 ◽  
Vol 81 (2) ◽  
pp. 933-942 ◽  
Author(s):  
C. J. De Ruiter ◽  
P. E. Habets ◽  
A. de Haan ◽  
A. J. Sargeant
Keyword(s):  
Cross Sections ◽  
Gastrocnemius Muscle ◽  
Periodic Acid ◽  
Medial Gastrocnemius ◽  
Periodic Acid Schiff ◽  
Fast Twitch ◽  
Medial Gastrocnemius Muscle ◽  
Stimulation Of

The purpose of the present study was to investigate to what extent fast-twitch IIX and IIB fiber recruitment was related to the natural existing muscle compartments (subvolumes of muscle innervated by different primary nerve branches) in rat medial gastrocnemius. Three groups (n = 6) of rats trotted on a motor-driven treadmill (20 degrees incline) at different speeds. A fourth group served as controls, and a fifth group received in situ electrical stimulation of all medial gastrocnemius muscle fibers. Postexercise glycogen levels (periodic acid-Schiff staining intensities) were made. Running caused more and in situ stimulation caused less glycogen breakdown in the proximal IIX and IIB fibers compared with the fibers of the same type in the most distal compartment. Furthermore, the boundaries of the most distal compartment could often be recognized in the periodic acid-Schiff-stained cross sections. It was concluded that during running the proximal IIX and IIB fibers were recruited to a greater extent (and at lower treadmill speeds) compared with the distal IIX and IIB fibers, respectively.

scholarly journals In vivo intramuscular fascicle-aponeuroses dynamics of the human medial gastrocnemius during plantarflexion and dorsiflexion of the foot

2009 ◽  
Vol 107 (4) ◽  
pp. 1276-1284 ◽  
Author(s):  
David D. Shin ◽  
John A. Hodgson ◽  
V. Reggie Edgerton ◽  
Shantanu Sinha
Keyword(s):  
Gastrocnemius Muscle ◽  
Imaging Techniques ◽  
High Stress ◽  
Proximal Region ◽  
Pennation Angle ◽  
Medial Gastrocnemius ◽  
Stress Concentrations ◽  
Fascicle Length ◽  
Medial Gastrocnemius Muscle

Velocity-encoded phase-contrast magnetic resonance (MR) imaging techniques and a computer-controlled MR-compatible foot pedal device were used to investigate the medial gastrocnemius muscle and aponeurosis deformations during passive and active eccentric movements of the plantarflexors. Intrafascicular strain, measured as the ratio of strain in the fascicle segment at its insertion to strain at its origin, was nonuniform along the proximodistal axis of the muscle ( P < 0.01), progressively increasing from the proximal to distal direction. The high intrafascicular strain regions appeared to correlate with the muscle regions that are likely to encounter high stress concentrations, i.e., the regions where the muscle physiological cross section decreases close to the tendons. The architectural gear ratio, i.e., the mechanical amplification ratio of fascicle length displacement to that of tendon/aponeuroses in a pennate muscle, also exhibited significant regional differences, with the highest ratios in the proximal region of the muscle accompanied by a higher initial pennation angle and a larger range of fascicular rotation about the origin. Values close to unity in the distal region of the muscle suggest that the aponeurosis separation may decrease in this region. Fascicle length and pennation angle changes were significantly influenced by force generation in the muscle, probably due to a shortening of the loaded muscle fibers relative to a passive condition. Overall, our data illustrate significant proximodistal intramuscular heterogeneity as supported by a regionally variable end-to-end strain ratio of fascicles and angle changes in the medial gastrocnemius muscle during passive and active ankle movements. These observations emphasize the need to reassess current conceptual models of muscle-tendon mechanics.

Active muscle stiffness in the human medial gastrocnemius muscle in vivo

2014 ◽  
Vol 117 (9) ◽  
pp. 1020-1026 ◽  
Author(s):  
Keitaro Kubo
Keyword(s):  
Gastrocnemius Muscle ◽  
Muscle Stiffness ◽  
Medial Gastrocnemius ◽  
Plantar Flexors ◽  
Active Muscle ◽  
Tendon Stiffness ◽  
Series Elastic Component ◽  
In Series ◽  
Medial Gastrocnemius Muscle

The aims of this study were to 1) directly assess active muscle stiffness according to actual length changes in muscle fibers (fascicles) during short range stretching; and 2) compare actual measured active muscle and tendon stiffness using ultrasonography with the stiffness of active (i.e., muscle) and passive (i.e., tendon) parts in series elastic component of plantar flexors using the alpha method. Twenty-four healthy men volunteered for this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated according to changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions [10, 30, 50, 70, and 90% maximal voluntary contractions (MVC)]. Using the variables measured during this fast stretch experiment, the stiffness of active (i.e., muscle) and passive (i.e., tendon) parts in plantar flexors was assessed using alpha method. Tendon stiffness was determined during isometric plantar flexion by ultrasonography. Active muscle stiffness increased with the exerted torque levels. At 30, 50, 70, and 90% MVC, there were no significant correlations between muscle stiffness using ultrasonography and stiffness of active part (i.e., muscle) by alpha method, although this relationship at 10% MVC was significant ( r = 0.552, P = 0.005). In addition, no correlation was noted in tendon stiffness between the two different methods ( r = 0.226, P = 0.209). The present study demonstrated that ultrasonography could quantified active muscle stiffness in vivo. Furthermore, active muscle stiffness and tendon stiffness using ultrasonography were not related to active (i.e., muscle) or passive (i.e., tendon) stiffness in series elastic component of plantar flexors by alpha method.

Efficiency of rat medial gastrocnemius muscle in contractions with and without an active prestretch

1989 ◽  
Vol 141 (1) ◽  
pp. 327-341 ◽  
Author(s):  
A. De Haan ◽  
G. J. Van Ingen Schenau ◽  
G. J. Ettema ◽  
P. A. Huijing ◽  
M. A. Lodder
Keyword(s):  
Gastrocnemius Muscle ◽  
High Energy ◽  
Medial Gastrocnemius ◽  
Stimulation Protocol ◽  
High Energy Phosphate ◽  
Concentric Contractions ◽  
Work Done ◽  
Positive Work ◽  
Medial Gastrocnemius Muscle

The efficiency of positive work was measured for rat medial gastrocnemius muscle at 25 degrees C during repeated contractions. Six muscles were stimulated to perform concentric contractions preceded by an active prestretch (PS contractions) and six muscles made to give concentric contractions from an isometric state (PI contractions). Both lengthening and shortening of the muscles (distance: 6 mm) occurred at a constant velocity of 20 mm s-1 (1.5 fibre lengths s-1). Stimulation was started 150 ms prior to the onset of concentric contraction for both types of contraction. For the PS contractions this meant that the active state was developed during the last 2.4 mm of the lengthening. Energy consumption (calculated from high-energy phosphate consumption) appeared to be equal for both types of contraction, although positive work output was 39.4% higher in the PS contractions than in the PI contractions. The efficiency of positive work was 36.8 +/− 3.5% in the PS contractions and 26 +/− 2.0% in the PI contractions. In contrast to results of previous studies, the positive work done by the muscle in the PS contractions was much larger than the negative work done on the muscle during stretch owing to the applied stimulation protocol which was intended to simulate in vivo conditions during running. The efficiency of positive work in the PS contractions is too low to explain the efficiencies of 40–70% reported for human and animal running.

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