The force curve ruler for exercise machines has one long side corresponding to the force curve of the associated muscle for whose training the relevant force curve ruler is inserted in the corresponding training machine. Both long sides can correspond to the force curve of two identical muscles ...
The capacity of a muscle to produce force is known to depend on the history of contraction.1, 2, 3 Contraction histories that lead to an increase in force compared to the force predicted by the force–length (FxL) and force–velocity relationship have been of special interest to the scienti...
The latter muscle also has a steeper normalized passive length force curve and produces more active tetanic force per gram muscle (877 g/g for gastrocnemius versus 379 g/g for semimembranosus).No differences between the semimembranosus and gastrocnemius are found with respect to the passive ...
However, almost all the isotonic data have been restricted to one length, l(0), the maximum length with almost no resting tension; the velocities measured are those initial values when the load begins to move. The force-velocity curve extrapolates to zero velocity for isometric tension, but ...
The length-tension relationship examines how changes in preload affect isometric tension development. When a muscle fiber contracts, it also shortens so that external work can be performed. If we were to isolate a piece of cardiac muscle and study the effects of afterload on the velocity of fibe...
Reconstruction of the Human Gastrocnemius Force–Length Curve in Vivo: Part 1—Model-Based Validation of Method The muscle fiber force–length relationship has been explained in terms of the cross-bridge theory at the sarcomere level. In vivo, for a physiologically r... SL Winter,JH Challis -...
The molecular bases of the Frank-Starling law of the heart and of its cellular counterpart, the length dependent activation (LDA), are largely unknown. However, the recent discovery of the thick filament activation, a second pathway beside the well-known
and then falls back to zero at about 160% resting length. Above resting length, the tension in the muscle is the sum of activeand passive components (seeFig. 2.23), which explains why we stretch (“preload”) muscles for a strong force exertion, such as in bringing the arm behind the ...
Force-frequency curves were examined, first in response to altered muscle length and second, following fatigue. There was no leftward shift in the curve when the knee extensors were shortened, although maximal force increased. In contrast, we observed a rightward shift in the curve after ...
Instead, the in situ length or an arbitrary but clearly defined reference length should be used. We propose the usage of "length adaptation" to describe the phenomenon whereby the length-force curve of a muscle shifts along the length axis due to accommodation of the muscle at different ...