scholarly journals Non-crossbridge stiffness in active muscle fibres

2016 ◽  
Vol 219 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Barbara Colombini ◽  
Marta Nocella ◽  
Maria Angela Bagni
Keyword(s):  
Muscle Fibres ◽  
Active Muscle

Light diffraction studies of active muscle fibres as a function of sarcomere length

1981 ◽  
Vol 2 (2) ◽  
pp. 215-224 ◽  
Author(s):  
Toshiharu Oba ◽  
Ronald J. Baskin ◽  
Richard L. Lieber
Keyword(s):  
Sarcomere Length ◽  
Light Diffraction ◽  
Muscle Fibres ◽  
Active Muscle

Storage and release of mechanical energy by active muscle: a non-elastic mechanism?

1985 ◽  
Vol 115 (1) ◽  
pp. 79-87 ◽  
Author(s):  
G. A. Cavagna ◽  
M. Mazzanti ◽  
N. C. Heglund ◽  
G. Citterio
Keyword(s):  
Isometric Contraction ◽  
Sarcomere Length ◽  
Mechanical Energy ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Elastic Recoil ◽  
Active Muscle ◽  
A Value ◽  
Elastic Mechanism ◽  
Isotonic Shortening

In frog muscle fibres, tetanically stimulated at a sarcomere length of about 2 micron, stretched at a velocity of 1 lengths-1 and released against a force equal to the maximum isometric, P0, a phase of rapid isotonic shortening takes place after release. As the amplitude of the stretch is increased from 1.5 to 9% of the initial length: (1) the amount of rapid isotonic shortening increases up to 9–10 nm per half sarcomere and (2) the stiffness of the fibre (an indication of the number of bridges attached) decreases to a value about equal to that measured during an isometric contraction. If a 5–10 ms delay is left between the end of stretch and release, the amount of rapid isotonic shortening increases to about 12 nm hs-1. A 300–500 ms delay, however, results in a decrease in rapid isotonic shortening to about 5 nm hs-1 and also results in a velocity transients against P0 that are similar to those described during release from a state of isometric contraction. It is concluded that the force attained after large, fast stretches is due to a greater force developed by each bridge and not to a greater number of bridges. After the elastic recoil (when the force is suddenly reduced to P0), these strained bridges are able to shorten by about 12 nm hs-1, suggesting that, during and immediately after stretching, they are charged to levels of potential energy greater than those attained in an isometric contraction.

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