Strain distribution within human triceps surae muscles during isometric contraction: in vivo study by Tagging MRI

Architectural properties of the triceps surae muscles complex were determined In Vivo for thirty subjects. These subjects were assigned to two groups. The first group of subjects consisted of 8 healthy men and the second group of subjects was composed of 22 patients with motor disorders. The ankle was positioned at -15 ° (dorsiflexion), and 0 ° (neutral anatomical position), and 15 °, and 30 ° (plantarflexion), with the knee set at 120 °and with an angle in the ankle joint of 90 °. At each position, longitudinal ultrasonic images of the Medial (MG) and Lateral (LG) Gastrocnemius and Soleus (SOL) muscles were obtained while the subject was relaxed (passive) and performed 50 % maximal voluntary isometric plantar flexion (active), from which fascicle Lengths (L) and angles (Θ) with respect to the aponeuroses were determined. From the ultrasonic image, it was observed that and Θ changed during an isometric contraction of the triceps surae muscle. Changes in L and were expressed as a function of relative torque. The Θ change was not identical for the three muscles. The fascicle Θ of MG demonstrated the greatest variation in three muscles. The effects of activation and relaxation positions were significant in all three muscles. The differences in MG fascicle Θ because of changes in ankle positions were significant among control and patients both in the passive and active conditions. Fascicle Θ of LG and SOL not differed among control and patient in the relaxation condition but not in the activation condition. For LG, and SOL ol fascicle Θ were changes were larger in control with the patients. The mean values fascicle Θ of MG, LG, and SOL an isometric contraction (50 % MVC) in the control groups increased by 60 %, 41 %, and 41 %, respectively; in the patient groups were a smaller increase, by 28 %, 26 %, and 36 %, respectively. Different lengths and angles of fascicles, and their changes bу contraction by patients and normal subjects, might bе related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses.

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Architectural and functional features of human triceps surae muscles during contraction

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.2.398 ◽

1998 ◽

Vol 85 (2) ◽

pp. 398-404 ◽

Cited By ~ 328

Author(s):

Yasuo Kawakami ◽

Yoshiho Ichinose ◽

Tetsuo Fukunaga

Keyword(s):

Plantar Flexion ◽

Triceps Surae ◽

Passive Condition ◽

Human Triceps Surae ◽

Functional Features ◽

The Subject ◽

Triceps Surae Muscles ◽

Ultrasonic Images ◽

Elastic Characteristics

Architectural properties of the triceps surae muscles were determined in vivo for six men. The ankle was positioned at 15° dorsiflexion (−15°) and 0, 15, and 30° plantar flexion, with the knee set at 0, 45, and 90°. At each position, longitudinal ultrasonic images of the medial (MG) and lateral (LG) gastrocnemius and soleus (Sol) muscles were obtained while the subject was relaxed (passive) and performed maximal isometric plantar flexion (active), from which fascicle lengths and angles with respect to the aponeuroses were determined. In the passive condition, fascicle lengths changed from 59, 65, and 43 mm (knee, 0°; ankle, −15°) to 32, 41, and 30 mm (knee, 90° ankle, 30°) for MG, LG, and Sol, respectively. Fascicle shortening by contraction was more pronounced at longer fascicle lengths. MG had greatest fascicle angles, ranging from 22 to 67°, and was in a very disadvantageous condition when the knee was flexed at 90°, irrespective of ankle positions. Different lengths and angles of fascicles, and their changes by contraction, might be related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses.

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MRI MEASUREMENT OF IN VIVO BEHAVIOR OF HUMAN TRICEPS SURAE DURING VOLUNTARY SUBMAXIMAL ISOMETRIC CONTRACTIONS

Medicine & Science in Sports & Exercise ◽

10.1097/00005768-200305001-02140 ◽

2003 ◽

Vol 35 (Supplement 1) ◽

pp. S384

Author(s):

A M. Lai ◽

J A. Hodgson ◽

T Finni ◽

V R. Edgerton ◽

J C. Puffer ◽

...

Keyword(s):

Triceps Surae ◽

Isometric Contractions ◽

Human Triceps Surae

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Production of hydroxyl radicals in contracting skeletal muscle of cats

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.3.1197 ◽

1996 ◽

Vol 81 (3) ◽

pp. 1197-1206 ◽

Cited By ~ 107

Author(s):

C. A. O'Neill ◽

C. L. Stebbins ◽

S. Bonigut ◽

B. Halliwell ◽

J. C. Longhurst

Keyword(s):

Skeletal Muscle ◽

Triceps Surae ◽

Oxygen Species ◽

Static Contraction ◽

Maximal Tension ◽

Cumulative Production ◽

Triceps Surae Muscles ◽

Specific Species

Reactive oxygen species increase during exhaustive contraction of skeletal muscle, but characterization of the specific species involved and their rates of production during nonexhaustive muscle contraction have not been investigated. We hypothesized that the production rate of hydroxyl radical (.OH) increases in contracting muscle and that this rate is attenuated by pretreatment with deferoxamine (Def) or dimethylthiourea (DMTU). We measured the rate of production of .OH before, during, and after 5 min of intermittent static contraction of the triceps surae muscles in cats (n = 6) using the formation of p-, m-, and o-tyrosines by hydroxylation of phenylalanine. L-Phenylalanine (30 mg/kg i.v.) was administered to each animal 3 min before contraction. Blood samples were collected from the popliteal vein 1 min before contraction; 1, 3, and 4.5 min during contraction; and 1 min after contraction. During and after contraction, the cumulative production rates of p-, m-, and o-tyrosines were elevated by 42.84 +/- 5.41, 0.25 +/- 0.04, and 0.21 +/- 0.03 nmol.min-1.g-1, respectively, compared with noncontracting triceps surae muscles. Pretreatment with Def (10 mg/kg i.v.; n = 5) or DMTU (10 mg/kg i.v.; n = 4) decreased the cumulative rates of production of p-, m-, and o-tyrosines during and after contraction. Additionally, the rate of tyrosine production increased in proportion to the percentage of maximal tension developed by the triceps surae muscles. These results directly demonstrate that .OH is produced in vivo in the skeletal muscle of cats during intermittent static contraction and that production can occur before the onset of fatigue.

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