Muscle Fiber Conundrum

[waynelucky2]

You basically recruit fewer fibers when moving slow, however a forum member says that there will be more overall tension on each of these fibers, than when all are recruited when moveing at a faster rep, say 1/1,

I do not not think this.

So and so states;
When you move a weight fast, you are recruited higher threshold motor units to do so, sharing the load amongst more motor units generates more force yes, but the actual tension placed on each of the muscle fibres is less due to more motor units being recruited.

Think 10 people pushing a car instead of 5

When you use a slow tempo you do 2 things.

1/ Recruit less motor units so less muscle fibres have to lift the same load, more tension is placed on these muscle fibres.

2/ Increase the TUT per recruited muscle fibre increasing fatigue.


Wayne states;

Lets say the biceps has 100 muscle fibers.

Lift 80% at 2/4, lets say this is 20 pounds, 20 pounds of tension on the biceps; the faster you lift the more tension is on the muscles. You can generate over 20 pounds of tension on 20 pounds when lifting fast. Just stand on a scale and side upright row 20 pounds; the scale will register about 25 pounds more.

DB curl 20 pounds slow 4/4, roughly 20 pounds of tension on the biceps, roughly 70% of muscle fibers recruited, 20 pounds divided by 70 muscle fibers = .2 pounds on each fiber.

DB curl 20 pounds fast 5/.5, roughly at least 40 pounds of tension on the biceps, 100 % of muscle fibers recruited, 40 divided by 100 muscle fibers = .4 pounds on each fiber.

The fibers recruited would not be this low but lets just add them up.

Same as above,

DB curl 20 pounds slow 4/4, roughly 20 pounds of tension on the biceps, roughly 70% of muscle fibers recruited, 20 pounds divided by 70 muscle fibers = .2 pounds on each fiber.

Now lets say the fast rep just recruited 70% if fibers, which it des not, and the tension on the muscles just went up by 5 pounds, which it would not,

DB curl 20 pounds slow 4/4, roughly 25 pounds of tension on the biceps, roughly 70% of muscle fibers recruited, 25 pounds divided by 70 muscle fibers = .3 pounds on each fiber.

As physics dictates the faster an object moves the more tension it will have. Just look at the faces of pilots when the G-forces hit, it just cant be the opposite.

Or as real World training dictates, if there was to be more tension placed on less muscle fibres, why do you fail faster in the faster reps, and not faster in the slow rep ???

Wayne

[N@tural1]

http://forum.bodybuilding.com/showpo...postcount=1727
http://forum.bodybuilding.com/showpo...postcount=1733
http://forum.bodybuilding.com/showpo...postcount=1734
http://forum.bodybuilding.com/showpo...postcount=1735
http://forum.bodybuilding.com/showpo...postcount=1737
http://forum.bodybuilding.com/showpo...postcount=1741


Answer: YOU NEED BOTH!

[all pro]

I posted this in another thread:

You need both. I absolutely HATE the either or mentality. You buy a 500 horsepower engine and install it in your car. But because you're smarter than the guy that designed it you decide a 2 barrel carburetor and single exhaust will work better than the super charger and tube headers that it was originally equipped with. Guess what happens the first time you take it up on the thruway and nail the accelerator to the floor. That's right, you get passed by a '72 Volkswagen beetle like you were sitting on jack stands. What happened to your 500 horsepower?
FUEL IN
EXHAUST OUT
What do 10 rep sets improve more so than 5 rep sets?
That's right, you got it. FUEL IN EXHAUST OUT
A 5 rep program will stall when strength gains out pace size gains.
A 10 rep program will stall when size gains out pace strength gains.
If your program is set up correctly and you can retire the 2Xs with heavy weight low rep sets and come right back with liter weight higher rep sets you will get the best of both worlds. 5 rep sets push strength gains straight up. 10 rep sets push size gains straight up. The trick is to find the right combination for 'YOU'.
4-6 reps + 8-12 reps
1-3 sets heavy 1-3 sets lite.
How many sets is something you have to find out for yourself. What works for me might not work for you. I use a six week cycle. 3x5 + 1x10. By week six I should be hitting failure on the first 5 rep set. Then I reduce the weight and start the cycle again. Twice per week.
1) -25 pounds / -20 pounds
2) -15 pounds / -10 pounds
3) -5 pounds / previous best weight for 3x5
4) +5 pounds / +10 pounds and so forth until failure happens on the first 5
5) rep set
6)
I use about 35% less weight for the pump set for 10-15 reps.
This is just an example. There are an endless variety of ways to set this up.

[N@tural1]

all pro

waynes issue is with fast reps.

he feels they are superiour to slow reps.

iv tried to explain that we cant say that one is better than another as both serve a slightly different function/purpose.

USE BOTH tempos!!

On a side note: Landau is being his usual self in the "Undeniable Bodybuilding" thread at D's.

LOL according to him powerlifters only use multi sets for skill development!

PMSL!

[Kelei]

all pro

waynes issue is with fast reps.

he feels they are superiour to slow reps.

iv tried to explain that we cant say that one is better than another as both serve a slightly different function/purpose.

USE BOTH tempos!!

On a side note: Landau is being his usual self in the "Undeniable Bodybuilding" thread at D's.

LOL according to him powerlifters only use multi sets for skill development!

PMSL!

Fast reps are better for 2B hypertrophy because these fibers do not reach peak tension at low speeds, moderate reps are better for 2A hypertrophy, slow reps are better for type 1 hypertrophy because these fibers require more time to reach peak tension levels.

To maximally stimulate your 2B fibers you must either,

1. Lift as fast as possible
2. Lift maximal loads

Basically it means that your 2B fibers are not being optimally stimulated unless you are attempting to apply the maximal amount of possible force you can generate at that point in time, regardless of fatigue or not, anytime you attempt to apply maximal force to a load you are calling your 2B fibers into action. While it is true that a set taken to failure with lighter weight (RE method) will also eventually call your 2B fibers into play, such a set does not require the 2B's to generate peak tension levels, instead they fire at lower tension levels for a more sustained period of time to support the failing 2A fiberr or lower threshold 2B fibers that have fatigued earlier.

[all pro]

all pro

waynes issue is with fast reps.

he feels they are superiour to slow reps.

iv tried to explain that we cant say that one is better than another as both serve a slightly different function/purpose.

USE BOTH tempos!!

On a side note: Landau is being his usual self in the "Undeniable Bodybuilding" thread at D's.

LOL according to him powerlifters only use multi sets for skill development!

PMSL!

On a side note: Landau is being his usual self in the "Undeniable Bodybuilding" thread at D's.

LOL according to him powerlifters only use multi sets for skill development!

Because according to him there are no different strength qualities. I already addressed this....twice. Did you miss it?

[waynelucky2]

Fast reps are better for 2B hypertrophy because these fibers do not reach peak tension at low speeds, moderate reps are better for 2A hypertrophy, slow reps are better for type 1 hypertrophy because these fibers require more time to reach peak tension levels.

To maximally stimulate your 2B fibers you must either,

1. Lift as fast as possible
2. Lift maximal loads

Basically it means that your 2B fibers are not being optimally stimulated unless you are attempting to apply the maximal amount of possible force you can generate at that point in time, regardless of fatigue or not, anytime you attempt to apply maximal force to a load you are calling your 2B fibers into action. While it is true that a set taken to failure with lighter weight (RE method) will also eventually call your 2B fibers into play, such a set does not require the 2B's to generate peak tension levels, instead they fire at lower tension levels for a more sustained period of time to support the failing 2A fiberr or lower threshold 2B fibers that have fatigued earlier.

Thx for the reply Kelei, however, what I was looking for was what do you think actually happens when doing a slow rep to a faster one,

1,
We know you basically recruit fewer fibers when moving slow, but will there be more overall tension on each of these fibers, than when all are recruited when moving at a faster rep, say 1/1, as we know when moving anything faster there is far more tension on whatever is moving.

Take a person trying to break a wooden plank with a blow, it would not break with a slow to medium speed, but would with a very fast speed.

Siff and Verkhoshansky used a force plate machine to determine the maximum effort a highly skilled weight lifter could display. This lifter generated 264 pounds of force on a 154 pound bar; 154 is 58% of 264. This demonstrates the optimal relationship between force and velocity, where speed strength is best developed.

Wayne

[all pro]

Wayne you are working the hell out of me. I'm answering your post on 2 boards. So I'm going to try to keep this quick and simple.

A fast contraction speed in the 1-6 rep range is SUPERIOR for increasing strength, power, myofibular hypertrophy and RFD.
A normal contraction speed in the 10+ rep range is SUPERIOR for increasing endurance and sarcoplasmic hypertrophy.
YOU NEED BOTH!

[jgreystoke]

^^^^^^^^

Sums it up.

Best of both worlds!

[N@tural1]

We know you basically recruit fewer fibers when moving slow, but will there be more overall tension on each of these fibers

I have already provided you exact links to Kelei posts on this subject.

Click > read.

Lifting 300 pounds in 0.5 seconds may generate 100 units of force and 50 units of tenson upon recruited fibers, although you actually recruit more fibers you are not increasing tension per fiber by recruiting additional motor units, because there are more motor units involved there is less tension placed upon each motor unit.

- Lifting 300 pounds in 2 seconds may generate 25 units of force and 100 units of tension upon recruited fibers, because there are less motor units recruited there is more tension placed upon those that are recruited.

To generate maximal tension you would need to lift as slow as possible on the concentric phase and as fast as possible on the eccentric phase.

1. Slow concentrics generate more tension than fast concentrics.
2. Fast eccentrics generate more tension than slow eccentrics.

-During a slow concentric there is less force being generated than during a fast concentric, this allows greater tension.
-During a fast eccentric there is less force being generated than during a slow eccentric, this allows greater tension.

Of course the eccentric is most important, because the weight is actually moving backwards so there obviously is less force being generated than when the weight is moving forwards (concentric), this allows greater tension, as force increases tension decreases, as force decreases tension increases.

[Defiant1]

3 ways for maximal tension:

Move as quickly as possible

Use as heavy a load as possible

Use a submaximal load to failure.


That's it.

Submaximal slowly does not create maximal tension. It is impossible.

Think about the physics.

The whole idea of "creating more tension within certain muscle fibers" does not follow muscle physiology.

[N@tural1]

D1

Whats your opinion that using a slower rep speed recruits less fibres, therfore the load is spread over less fibres therfore more actual tension (or stress) on the fibres that are recruited as Kelei has explained?

[Defiant1]

D1

Whats your opinion that using a slower rep speed recruits less fibres, therfore the load is spread over less fibres therfore more actual tension (or stress) on the fibres that are recruited as Kelei has explained?

Well, the tension CAN'T be higher, or more motor units would be recruited. I think people are confusing perceived effort with actual effort.

Force recruits motor units. F = m x a. Intentionally slow movement reduces both m AND a.

You COULD say that you could focus on lower threshold units because you are not working the higher threshold MUs, but not with increased tension per unit.

An example of this is jogging.

[N@tural1]

Well, the tension CAN'T be higher, or more motor units would be recruited.

I think the actual deliberate act of moving slower prevents HTMU recruitment initialy (untill they are needed of course)

I think people are confusing perceived effort with actual effort.

I think the confusion is between max recruitment and actual "stress" to each fibre - tension

You COULD say that you could focus on lower threshold units because you are not working the higher threshold MUs, but not with increased tension per unit.

An example of this is jogging.

But with jogging there is no load

We'r talking moving a load in the typical bodybuilding rep range 60-75% 1rm - at a slower tempo.


I can see what Kelei was trying to say.

When you deliberatly fire your HTMU by repping fast, you're spreading the load over a greater amount of fibres.

When repping slower, you're recruiting less fibres to move the same load.

Therfore the force generated to move the load is the responsibility of less fibres (initialy)

Think - 5 people trying to move a heavy fridge instead of 10

The more people (fibres) the more the load is spread.

[Squat-Man]

D1

Whats your opinion that using a slower rep speed recruits less fibres, therfore the load is spread over less fibres therfore more actual tension (or stress) on the fibres that are recruited as Kelei has explained?

Natural2 there is nothing wrong with the idea that Kelei explained but when focusing on this we miss the other points. For example when using slower speeds fast twitch fibers will not be recruited much and as a result this will greatly decrease the load and tension. Kelei's explanations are right about tension but that's not explaining the whole parts of the puzzle. Let's make an assumption ' Would more tension be occured if we would perform the negative phase of the exercises fast and positive phase of the movements slowly and keep TUT let's say between 40-70.' Answer is NO because performing reps in this style would lower the load much and this would lower the tension with a significant degree. I guess Kelei will agree with this.

[Defiant1]

I think the actual deliberate act of moving slower prevents HTMU recruitment initialy (untill they are needed of course)



I think the confusion is between max recruitment and actual "stress" to each fibre - tension



But with jogging there is no load

We'r talking moving a load in the typical bodybuilding rep range 60-75% 1rm - at a slower tempo.


I can see what Kelei was trying to say.

When you deliberatly fire your HTMU by repping fast, you're spreading the load over a greater amount of fibres.

When repping slower, you're recruiting less fibres to move the same load.

Therfore the force generated to move the load is the responsibility of less fibres (initialy)

Think - 5 people trying to move a heavy fridge instead of 10

The more people (fibres) the more the load is spread.

It doesn't work like that. When you would get to a certain level of force needed, then you would recruit more fibers, not fatigue the original ones.

In your "5 people" analogy, there are ALWAYS 10 people present. 6-10 will help if necessary. Always.

The reason you are only recruiting the lower number of fibers is that the force requirement is low. So to say you are moving the same load with less fibers is NOT correct. The load is the same ONLY in terms of "weight", but not actual "load" on the muscle.

Again, if you want to say you are focusing on the lower threshold units by AVOIDING using the higher threshold units, then that is okay. But not because you are generating the same tension spread between fewer fibers. You are generating less tension.

[N@tural1]

Natural2 there is nothing wrong with the idea that Kelei explained but when focusing on this we miss the other points. For example when using slower speeds fast twitch fibers will not be recruited much and as a result this will greatly decrease the load and tension.

It seems I spend alot of time on this board trying to defend Kelei, the fact is he KNOWS that there is more to the picture, he made those posts simply to explain the relationship between force and tension.

He then followed on to explain HIMSELF that he knows its just a small part of the picture.

Of course you need both, I wasnt suggesting which way to train, just stating information, I was hoping that most people would have enough brain power to consider the information and put the picture together for themselves.

All I said was that slow concentrics generate greater tension than fast concentrics, and that fast eccentrics generate more tension than slow eccentrics, I wasn't trying to say which is best because that entirely depends on your training goals.

Of course there is more to hypertrophy than simply tension, but I was simply talking about tension itself, I wasn't talking about hypertrophy. Basically all I told you guys was how rep speeds influence tension and motor unit recruitment, that's all. If I was to explain to you how a bullet works then you should take it for what it is, I am not trying to explain how the entire gun and all it's components work in relation to the bullet, I am simply talking about the bullet.

You agreed!

You are right about the relationship between force and tension also for fast reps more motor units will be recruited. No need to argue these.

Maybe you just forgot about these posts?

Kelei's explanations are right about tension but that's not explaining the whole parts of the puzzle.

See above.

Kelei just simply took the time to explain the relationship between force and tension. he never suggested that how we all train 100% of the time.

Like everything, its a tool

[Defiant1]

Slow concentrics DO NOT generate more tension than fast concentrics.

F = m x a. You are reducing a. You are reducing force.

He is correct about fast eccentrics.

[N@tural1]

It doesn't work like that. When you would get to a certain level of force needed, then you would recruit more fibers, not fatigue the original ones.

Performing an explosive rep speed would recruit more fibres than if rep speed was slow. You feel thats correct?

In your "5 people" analogy, there are ALWAYS 10 people present. 6-10 will help if necessary. Always.

Yes you are exactly right, but wouldnt they only be necessary if the actual speed of movement increased OR as the others fatigued?

But not because you are generating the same tension spread between fewer fibers. You are generating less tension.

I think we may be viewing tension and force differently.

D1, why in your opinion is it that the eccentric movement stimulates more hypertrophy than the concentric?

[N@tural1]

F = m x a. You are reducing a. You are reducing force.

Thats what Kelei was saying, by generating less force you create greater tension on the recruited fibres.

Maybe we are defining force and tension differently

[Defiant1]

Performing an explosive rep speed would recruit more fibres than if rep speed was slow. You feel thats correct?

Depends if the force was beyond threshold.

Yes you are exactly right, but wouldnt they only be necessary if the actual speed of movement increased OR as the others fatigued?

As I said, if you want to focus on the Lower TMUs, then it is fine. But it doesn't create the same tension spread throughout less fibers. It can't.

D1, why in your opinion is it that the eccentric movement stimulates more hypertrophy than the concentric?

I don't necessarily believe that. Most studies that show that are comparing isokinetics (no negatives AT ALL) v. eccentric movement.

In fact, the evidence is that FAST eccentrics are better than SLOW eccentrics.

http://www.ncbi.nlm.nih.gov/sites/en...RVAbstractPlus

http://www.ncbi.nlm.nih.gov/sites/en...indexed=google

[Defiant1]

Thats what Kelei was saying, by generating less force you create greater tension on the recruited fibres.

Maybe we are defining force and tension differently

Not "greater", more like "only". The idea of creating the SAME force or tension with less recruitment doesn't make sense.


It's simply working at less than your capacity.

[waynelucky2]

Wayne you are working the hell out of me. I'm answering your post on 2 boards. So I'm going to try to keep this quick and simple.

A fast contraction speed in the 1-6 rep range is SUPERIOR for increasing strength, power, myofibular hypertrophy and RFD.
A normal contraction speed in the 10+ rep range is SUPERIOR for increasing endurance and sarcoplasmic hypertrophy.
YOU NEED BOTH!

Yup I agree.

Wish over at Ellingtons you would not say slow reps, as I imagine you mean on using 80% of your 1RM, that a fast contraction speed is as fast as possible or roughly .5/.5 and a normal contraction speed is 1/1 ???

As they think you are backing them up when you say slow speeds, which you did earlier

Wayne

[N@tural1]

D1 this is what Im trying to explain.

""You lower the weight by turning off some motor units.
This decreases the force exerted by your muscle on the
weight. Once the downward force of the weight is a bit
greater than the muscular force, the weight moves
downward under control. Thus, fewer motor units are
recruited to lower the weight under control than to hold the
weight stationary.""

""A motor unit performs work when it contracts against
an external load, such as a barbell. The load also exposes
the motor unit to tension, which damages the motor unit.
The motor unit receives a consequent growth stimulus that
causes hypertrophy of the motor unit when it gets repaired.
The more tension placed on the motor unit, the greater is
the growth stimulus experienced by the motor unit (within
reason, of course). This is one reason why lifting heavy
weights is more productive for muscle growth than staying
with lighter weights.
The key to understanding negatives lies in the
recruitment of motor units, discussed above. When motor
units are turned off to lower a weight, a decreasing number
of motor units are left holding the weight. These
remaining motor units are thus exposed to a greater level
of tension, which provides an opportunity for a greater
growth stimulus.""

"Suppose youre going to use a muscle comprised of
ten motor units to lift a weight of 100 lbs. When you lift
the weight, all of the motor units participate, as shown in
Figure 2. Because all ten motor units participate, the
weight exposes each motor unit to 10 lbs of tension. Once
youve lifted the weight, you lower it by turning off some
motor units. Lets suppose that you turn off three motor
units, as shown in Figure 3. This leaves seven motor units
to lower the weight under control. Because there are now
fewer motor units supporting the weight, each motor unit
is exposed to more tension""

""Since each motor unit is exposed to greater tension
during the eccentric portion of the lift, the eccentric
portion is a bit more inclined to produce a growth stimulus.""

http://www.ridgely.ws/publications/eccentric-reps.pdf

[Defiant1]

D1 this is what Im trying to explain.

""You lower the weight by turning off some motor units.
This decreases the force exerted by your muscle on the
weight. Once the downward force of the weight is a bit
greater than the muscular force, the weight moves
downward under control. Thus, fewer motor units are
recruited to lower the weight under control than to hold the
weight stationary.""

""A motor unit performs work when it contracts against
an external load, such as a barbell. The load also exposes
the motor unit to tension, which damages the motor unit.
The motor unit receives a consequent growth stimulus that
causes hypertrophy of the motor unit when it gets repaired.
The more tension placed on the motor unit, the greater is
the growth stimulus experienced by the motor unit (within
reason, of course). This is one reason why lifting heavy
weights is more productive for muscle growth than staying
with lighter weights.
The key to understanding negatives lies in the
recruitment of motor units, discussed above. When motor
units are turned off to lower a weight, a decreasing number
of motor units are left holding the weight. These
remaining motor units are thus exposed to a greater level
of tension, which provides an opportunity for a greater
growth stimulus.""

"Suppose youre going to use a muscle comprised of
ten motor units to lift a weight of 100 lbs. When you lift
the weight, all of the motor units participate, as shown in
Figure 2. Because all ten motor units participate, the
weight exposes each motor unit to 10 lbs of tension. Once
youve lifted the weight, you lower it by turning off some
motor units. Lets suppose that you turn off three motor
units, as shown in Figure 3. This leaves seven motor units
to lower the weight under control. Because there are now
fewer motor units supporting the weight, each motor unit
is exposed to more tension""

""Since each motor unit is exposed to greater tension
during the eccentric portion of the lift, the eccentric
portion is a bit more inclined to produce a growth stimulus.""

http://www.ridgely.ws/publications/eccentric-reps.pdf

I don't agree with the conclusions posted there.

Check out the links I posted re: fast v slow eccentrics.

[waynelucky2]

Depends if the force was beyond threshold.



As I said, if you want to focus on the Lower TMUs, then it is fine. But it doesn't create the same tension spread throughout less fibers. It can't.





I don't necessarily believe that. Most studies that show that are comparing isokinetics (no negatives AT ALL) v. eccentric movement.

In fact, the evidence is that FAST eccentrics are better than SLOW eccentrics.

http://www.ncbi.nlm.nih.gov/sites/en...RVAbstractPlus

http://www.ncbi.nlm.nih.gov/sites/en...indexed=google

Yup thats what I think now, but thought before (ok last three years) positives fast negatives slow, but not anymore, please give my post a read Defiant, as 3 second negatives are fantastic.

http://www.drdarden.com/readTopic.do?id=478850

Wayne

[all pro]

Nat2 I know I've used analogies before to explain this stuff. But all you need to understand is that the 2X group is out of fuel in 5-10 seconds. They'll be recruited but they aren't going to respond. No damage. No hypertrophy. If they get a training effect it will a conversion to a slower type. In the mean time as you near failure the CNS increases it's firing rate an the 2As take a pounding. Some of them will be retired due to damage. They will come back bigger and stronger. Some of them will run out of fuel. They will adapt to a slower type with improved endurance. That's why I do the heavy stuff first. If I damage the 2xs first in a 5 rep set they wont be available for a 10 rep set. The 2Xs will get bigger and stronger as will some of the 2As and the remainder of the 2As will gain endurance. Either or, like singe factor non-mixed qualities is a loser. Think outside the box and get greedy. Try to improve across the board.

[N@tural1]

""The relationship between force (tension) development and velocity (rate) of muscle contraction is said to be inverse. In this sense, eccentrics are considered "slower" than isometric contractions, and isometrics are considered "slower" than concentric contractions. Eccentric contractions can develop more tension than isometric contractions, and isometric contractions can develop more tension than concentric contractions. However, it may be clearer to consider each type of contraction individually. Faster concentric contractions develop less tension than slower concentric contractions. Faster eccentric contractions develop more tension than slower eccentric contractions. Isometric contractions develop more tension than concentrics, but less than eccentrics.""

http://academic.uofs.edu/faculty/kos...5/forcevel.htm

[waynelucky2]

Well, the tension CAN'T be higher, or more motor units would be recruited. I think people are confusing perceived effort with actual effort.

Force recruits motor units. F = m x a. Intentionally slow movement reduces both m AND a.

You COULD say that you could focus on lower threshold units because you are not working the higher threshold MUs, but not with increased tension per unit.

An example of this is jogging.

We are taking of moving 80%

At first I thought hmm, that sounds right, but it just cant be, so then I thought, the faster you move a weight the more tension it pusts on the muscles, just jump on a scale and this is easily proved, thus as proved above in my first post, there will be more tension on each of the more fibers that are recruited.

Siff and Verkhoshansky used a force plate machine to determine the maximum effort a highly skilled weight lifter could display. This lifter generated 264 pounds of force on a 154 pound bar; 154 is 58% of 264. This demonstrates the optimal relationship between force and velocity, where speed strength is best developed.

Thus huge tensions on the muscle fibers compeered to the less fibers being recruited on the slow reps.

BIG THX for all the answers, I am now going out for a quite beer, will catch up on the debate tomorrow.

NEARLY forgot, and you all should like this, I E-mailed Roger M. Enoka the question, but as most know the way I put things is not that good, but I good a reply. Now I have sent a re-wrote letter.

Roger M. Enoka wrote,

Wayne,

The force that a muscle must exert to move a load depends on two factors: the mass of the load and the amount of acceleration imparted to the load. The number of muscle fibers recruited during the lift increases with the speed the lift.

I hope this helps.


Roger M. Enoka, Ph.D.
Professor and Chair
Department of Integrative Physiology
University of Colorado
Boulder, CO 80309-0354, USA
Phone: 303-492-7232
Fax: 303-492-6778

Wayne

[N@tural1]

The number of muscle fibers recruited during the lift increases with the speed the lift.

Exactly what Iv been saying.