[b said:
Quote[/b] (dkm1987 @ Oct. 02 2005,7:55)]Ok, I admit it I'm lost with that JV,
If you are saying force(tension) increases with speed? No, it doesn't.
I was thinking of the force applied on it, and so were the examples. Now that I look at them, they do seem vague. They're nothing complicated at all. It's only elementary physics I took right from my book, I just didn't label them enough, just typed them in a rush, sorry.
(And yeah, "Speed", velocity, isn't what changes tension. That would be saying F=mv, which is under Aristotle. We civilized modern people already follow Netwon, F=ma, acceleration, not velocity, so the rep speed itslef is not our concern)
For muscles, I chose the tensile stress model because it was simpler, and seeing as to how in tension they were.
We aren't actually increasing "speed" itslef, only the acceleration is actually important, but there's no way to do that without increasing speed (but that's not meaning the reps and sets will have to be faster as a whole movement). Since acceleration is what matters, it can be applied or demonstrated without much problem. We slow down the eccentric as needed, stop a little at the end (you don't even have to notice it actually, we simply do so as a habit since we avoid using momentum to swing the weights), giving us a starting velocity (for the concentric motion) of zero. Increasing the acceleration is obviously reaching a higher speed by the end of the motion - or at least somewhere along the motion, most naturally near the end. Comparing that is easy. If it takes you 1 second versus 2 seconds to complete the concentric part, you most probably have a greater acceleration. Same load, different acceleration. In effect, greater force is needed. (It's like the relationship of power and mass. More power is needed to move a certain mass in less time, less power needed if the time is longer - given of course that we are talking of the same distance in both cases.) The reps (and consequently also the sets) can be (as one whole movement) faster or slower, whatever you decide, as long as the acceleration is increased, which is what will produce greater force and a little more peak tension. Considering TTI is a different matter, since all we're concerned about here (I mean in this particular discussion) is increasing force, which is a tricky matter if you don't change the load.
I'm thinking more in physics, so that was what initially registered to me when you mentioned the formula for work. You can increase force by increasing acceleration. This only applies for the concentric part. It does increase peak tension by doing it faster there. Not in the eccentric.
You may (but shouldn't really) look at it in another point of view that may be simpler to understand (still physics though, sorry, I'm actually trying to forget that book, but you know what they say about every first thing that you've done). Increasing your acceleration makes you apply a greater force on anything (relative to a slower same thing you apply, for example, a punch or a kick). In this case we apply a force on a bar with weights attached to it. The force we apply on it is of course applied back to us, Newton's third law, and so our muscles get the same force applied on them which is of course spread evenly on their cross-sectional area (A). The more force you apply on it, the more force is applied to you. This model won't really hold so well, since not all the force applied will always be actually become force applied on the muscles only (and remember, you aren't always rock solid, so treat some force as "dissipated" when your body moves a little or is pushed back a little; also, actually applying tension force model here would be a little complicated since muscles involved are far from being massless ropes that are commonly used to simplify problems in physics that I'm sure you all remember one time or another. And, it's not really just the weightlifter-and-barbell system that we actually have to look at; like the regular college stumper of the "horse-and-cart" problem, we have to look at whatever we're gounded on during a lot of lifts.)
If you are already doing the concentric part as fast as you can, there is no way you can probably do this. But if you find that you are actually doing it a little slower, and you do all those mighty number of reps (again assuming we don't increase the load) and you hit your plateau, you can increase force and so tension by increasing your acceleration. This here is just peak tension. If you want TUL (other than increasing your already numerous reps we assumed), you can perhaps stop also at the top of the movement, or slow down the eccentric more, or whatever you can think of.
So we aren't actually really increasing the reps speed or "making the reps faster". Faster or slower, whatever you decide, as long as you increase the acceleration.
