Length-tension relationship :: Sliding filament theory
The relationship between tension and intracellular calcium concentration ([Ca2+]i ) in intact frog skeletal muscle fibres was determined at two fibre lengths. The length-tension relationship can likely be explained by interactions between two underlying mechanisms: the active and passive length-tension relationships. In this video, learn about concentric/eccentric/isometric contraction and the length -tension relationship of muscle. Understand the passive.
Training-specific muscle architecture adaptation after 5-wk training in athletes. Influence of concentric and eccentric resistance training on architectural adaptation in human quadriceps muscles.
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Journal of sports sciences, 31 14 Short Muscle Length Eccentric Training. Frontiers in Physiology, 7. Neuromuscular adaptations to isoload versus isokinetic eccentric resistance training. The muscles then converts the isometric tension to isotonic contraction which enables the blood to be pumped out when they finally contract. The heart has an intrinsic control over the stroke volume of the heart and can alter the force of blood ejection. Force-velocity relationship Cardiac muscle has to pump blood out from the heart to be distributed to the rest of the body.
It has 2 important properties that enable it to function as such: It carries a preload, composed of its initial sarcomere length and end-diastolic volume. This occurs before ejecting blood during systole. This is consistent with Starling's law which states that: Force-velocity relationship in cardiac muscles.
At rest, the greater the degree of initial muscle stretch, the greater the preload. This increases the tension that will be developed by the cardiac muscle and the velocity of muscular contraction at a given afterload will increase. Upon stimulation of cardiac muscle, it develops isometric tension without shortening. Once enough tension has accumulated, the muscle can now overcome the afterload and eject the blood it was carrying. Tension however is maintained at this stage. Tension is greater in muscle stretched more initially as the preload at a given velocity for muscular shortening.
The same muscle with a shorter resting length has a lower tension in comparison. These observations are consistent with the length-tension relationship. They can't do their work. And so even though you get some force of contraction, it wouldn't be maximal. So I'll put something like this.
Length tension relationship | S&C Research
This will be our second spot. This will be number two. Now in number three, things are going to get much better. So you'll see very quickly now you have a much more spread out situation. Where now these are actually-- these actins are really not going to be in the way of each other.
You can see they're not bumping into each other, they're not in the way of each other at all. And so all of the myosins can get to work.
So the z-discs are now out here.
My overall sarcomere, of course, as I said, was from z-disc to z-disc. So my sarcomere is getting longer. And you can also see that because now there's more titin, right? And there isn't actually more titin. I shouldn't use that phrase. But the titin is stretched out. So here, more work is going to get done.
And now my force, I would say, is maximal. So I've got lots, and lots of force finally. And so it would be something like this. And so based on my curve, I've also demonstrated another point, which is that, the first issue, getting us from point one to point two, really helped a lot. I mean, that was the big, big deal. Because you needed some space here.
Again, this space really was necessary to do work at all. And now that we've gotten rid of the overlap issue, now that we've gotten these last few myosins working, we have even more gain.
Length tension relationship
But the gain was really-- the biggest advantage was in that first step. Now as we go on, let's go to step four. So this is step four now. As we go here, you're going to basically see that this is going to continue to work really well. Because you have your actin, like that, and all of your myosins are still involved in making sure that they can squeeze. So all the myosins are working.
And our titin is just a little bit more stretched out than it was before. And our force of contraction is going to be maximal. And you're going to have-- and so here, I'm drawing the z-discs again. They're very spread out. Our sarcomere is getting longer and longer. And our force of contraction is the same.
Now let's just take a pause there and say, why is it the same? Why did it not go up? Well, it's because here, in stage three, you had 20 myosin heads working. Up here, you had something like 16 out of 20 working.
The cellular basis of the length-tension relation in cardiac muscle.
Here, we said maybe zero out of 20 right? And here, you again have 20 out of So you still have an advantage in terms of all of the myosins working. But there's no difference between 0. Because again, all the myosins are working. So now in stage five, we kind of take this a little too far, right?