T Nation

The Question I Dont Think Anyone Will Be Able To Answer

Hi there all,

A forum member states the below, but I just can not see this, 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.

A forum member 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 50 pounds, 50 pounds of tension on the biceps; the faster you lift the more tension is on the muscles. You can generate over 100 pounds of tension on 50 pounds when lifting fast. Just stand on a scale and side upright row 80%.

DB curl 50 pounds slow 4/4, roughly 50 pounds of tension on the biceps, roughly 70% of muscle fibers recruited, 70 divided by 50 = .7pounds on each fiber.

DB curl 50 pounds fast 5/.5, roughly 105 pounds of tension on the biceps, 100 % of muscle fibers recruited, 100 divided by 105 = 1.05 pounds on each fiber.

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

DB curl 50 pounds slow 4/4, roughly 50 pounds of tension on the biceps, roughly 50% of muscle fibers recruited, 50 divided by 50 = 1 pounds on each fiber.

DB curl 50 pounds fast 5/.5, roughly 105 pounds of tension on the biceps, 100 % of muscle fibers recruited, 100 divided by 105 = 1.05 pounds on each fiber.

The biceps even thou they only use a lower about of muscle fiber when repping slow would contract as a whole, this can easily be seen, just curl very slowly and look at your biceps not contract that much, now curl very far, and see the biceps contract very hard.

By the way I am into faster style repping, as I dont see much point in slower than 2/2.

Wayne

[quote]waynelucky wrote:
Hi there all,

A forum member states the below, but I just can not see this, 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.

A forum member 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 50 pounds, 50 pounds of tension on the biceps; the faster you lift the more tension is on the muscles. You can generate over 100 pounds of tension on 50 pounds when lifting fast. Just stand on a scale and side upright row 80%.

DB curl 50 pounds slow 4/4, roughly 50 pounds of tension on the biceps, roughly 70% of muscle fibers recruited, 70 divided by 50 = .7pounds on each fiber.

DB curl 50 pounds fast 5/.5, roughly 105 pounds of tension on the biceps, 100 % of muscle fibers recruited, 100 divided by 105 = 1.05 pounds on each fiber.

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

DB curl 50 pounds slow 4/4, roughly 50 pounds of tension on the biceps, roughly 50% of muscle fibers recruited, 50 divided by 50 = 1 pounds on each fiber.

DB curl 50 pounds fast 5/.5, roughly 105 pounds of tension on the biceps, 100 % of muscle fibers recruited, 100 divided by 105 = 1.05 pounds on each fiber.

The biceps even thou they only use a lower about of muscle fiber when repping slow would contract as a whole, this can easily be seen, just curl very slowly and look at your biceps not contract that much, now curl very far, and see the biceps contract very hard.

By the way I am into faster style repping, as I dont see much point in slower than 2/2.

Wayne
[/quote]

Wayne, you didn’t ask a question.

Before you do, consider what happens with an isometric contraction - when done correctly almost all motor units are recruited even though there is no movement. Movement and actual velocity are NOT required for motor units recruitment - 1000 pound squats are possible because rep speed does not matter for recruiting all available motor units.

I would go as far as to say that when it comes to max lifts, NO ONE will have a higher max at fast speed than slower speed.

One final thing concerning “By the way I am into faster style repping, as I dont see much point in slower than 2/2”. That’s fine that you don’t lift that way, but many do and since that is the case you don’t have the luxury of operationally defining reality.

That’s basically “majoring in the minors”. In other words, who really gives a crap how long it takes you to complete a rep. How many really big guys do you think worried about whether they were using a X0X rep cadence or 313 cadence along their path to getting big. Maybe a couple, but not the majority.

You also have to take into consideration the load they are using, their level of fatigue, the exercise in question, etc…

Just lift the damn weight and control it down on the negative. Anything more complicated than that is just making mountains out of molehills.

[quote]905Patrick wrote:
waynelucky wrote:

Wayne, you didn’t ask a question.
[/quote]

Thought I was going crazy for a minute.

[quote]Airtruth wrote:
905Patrick wrote:

Wayne, you didn’t ask a question.

Thought I was going crazy for a minute.[/quote]

Heh heh, it was odd. I read the post three times and eventually did a search for a question mark.

[quote]… 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.

[/quote]

Um, ‘tension’? An object gains ‘tension’ as it moves?

Relativistically, it gains MASS as it goes faster.

But ‘tension’?

Tension is what causes a pilot’s face to get pulled back when experiencing ‘g-forces’?

Where’d you get your doctorate?

This is way too overly complicated, I stopped reading it after the 2nd paragraph. Eat big, lift heavy, sleep. Much simpler!

[quote]josh86 wrote:
This is way too overly complicated, I stopped reading it after the 2nd paragraph. Eat big, lift heavy, sleep. Much simpler![/quote]

AMEN.

(but funny how that seems too hard to a lot of people as well)

[quote]Sentoguy wrote:
That’s basically “majoring in the minors”. In other words, who really gives a crap how long it takes you to complete a rep. How many really big guys do you think worried about whether they were using a X0X rep cadence or 313 cadence along their path to getting big. Maybe a couple, but not the majority.

You also have to take into consideration the load they are using, their level of fatigue, the exercise in question, etc…

Just lift the damn weight and control it down on the negative. Anything more complicated than that is just making mountains out of molehills.

[/quote]

Quoted for goodness. [/end thread]

You’re forgetting about our friend Mr. Gravity.

Doesn’t CT say rack pulls and long lock-outs are actually great for muscle growth but officially you’re not actually doing any “work”.

[quote]Sentoguy wrote:
That’s basically “majoring in the minors”. In other words, who really gives a crap how long it takes you to complete a rep. How many really big guys do you think worried about whether they were using a X0X rep cadence or 313 cadence along their path to getting big. Maybe a couple, but not the majority.

You also have to take into consideration the load they are using, their level of fatigue, the exercise in question, etc…

Just lift the damn weight and control it down on the negative. Anything more complicated than that is just making mountains out of molehills.

[/quote]


You mean lift the weight as fast and you can, regardless of how fast it actually moves, and then control the eccentric.

[quote]LightsOutLuthor wrote:
… 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.

Um, ‘tension’? An object gains ‘tension’ as it moves?

Relativistically, it gains MASS as it goes faster.

But ‘tension’?

Tension is what causes a pilot’s face to get pulled back when experiencing ‘g-forces’?

Where’d you get your doctorate?
[/quote]

I studied with Sir Newton.

What I was trying to say was, if you curl 50% slow there will not be that much muscle tension on the biceps, curl it very fast and there will be very high biceps muscle tension.

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

[quote]josh86 wrote:
This is way too overly complicated, I stopped reading it after the 2nd paragraph. Eat big, lift heavy, sleep. Much simpler![/quote]

Yep I know its complicated, but its a question that has never come up, and thought it would be fun to see if anyone really knew the answer.

Wayne

[quote]905Patrick wrote:
Airtruth wrote:
905Patrick wrote:

Wayne, you didn’t ask a question.

Thought I was going crazy for a minute.

Heh heh, it was odd. I read the post three times and eventually did a search for a question mark.[/quote]

Yes there was a question, which do you think was/is right ??? The forum member statement or mine Waynes statement. As both of us as you will see have different views on the subject.

Do you think a slow rep puts more tension on just a few muscle fibers, or a fast rep puts more tension on all muscle fibers.

forum member 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 50 pounds, 50 pounds of tension on the biceps; the faster you lift the more tension is on the muscles. You can generate over 100 pounds of tension on 50 pounds when lifting fast. Just stand on a scale and side upright row 80%.

DB curl 50 pounds slow 4/4, roughly 50 pounds of tension on the biceps, roughly 70% of muscle fibers recruited, 70 divided by 50 = .7pounds on each fiber.

DB curl 50 pounds fast 5/.5, roughly 105 pounds of tension on the biceps, 100 % of muscle fibers recruited, 100 divided by 105 = 1.05 pounds on each fiber.

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

DB curl 50 pounds slow 4/4, roughly 50 pounds of tension on the biceps, roughly 50% of muscle fibers recruited, 50 divided by 50 = 1 pounds on each fiber.

DB curl 50 pounds fast 5/.5, roughly 105 pounds of tension on the biceps, 100 % of muscle fibers recruited, 100 divided by 105 = 1.05 pounds on each fiber.

The biceps even thou they only use a lower about of muscle fiber when repping slow would contract as a whole, this can easily be seen, just curl very slowly and look at your biceps not contract that much, now curl very fast, and see the biceps contract very hard.

By the way I am into faster style repping, as I dont see much point in slower than 2/2.

Wayne

The key to determining MU recruitment is internal muscular tension, not external muscular force.

Fast reps are effective because you have to recruit a large number of the available MU’s to move the weight fast, and it is probably more sport specific.

Slow reps are effective because you only use a few MU’s early on, which get fatigued, which in turn means you must recruit more MU’s to keep going. There is tremendous intramuscular tension at the end of a tough set.

Isometrics also work as an above poster pointed out. So the answer is you both are correct, lifting fast recruits a lot of MU’s and so does lifting slow when it is taken to fatiguing levels.

Rep per rep, fast is better, but you have to look at the whole set, not just one fast rep vs one slow rep.

[quote]waynelucky wrote:
LightsOutLuthor wrote:
… 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.

Um, ‘tension’? An object gains ‘tension’ as it moves?

Relativistically, it gains MASS as it goes faster.

But ‘tension’?

Tension is what causes a pilot’s face to get pulled back when experiencing ‘g-forces’?

Where’d you get your doctorate?

I studied with Sir Newton.

What I was trying to say was, if you curl 50% slow there will not be that much muscle tension on the biceps, curl it very fast and there will be very high biceps muscle tension.

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[/quote]

Well, think of the tension on a bridge cable. It doesn’t really ‘move’ per se, but the force of the gravity on the bridge is equal and opposite the force on the cable.

The idea of slowing down seems to make sense until you realize that in the case of a weight that is CONSTANT, you’re not changing anything other than the force you’re using to pull it up, by changing the acceleration (which can be the change in speed or DIRECTION of the speed).

I’ll think about it more, but I think the question is needing some fleshing out because the fact that velocity and acceleration and tension are all vector forces, and are related to direction as well as value.

But, like all the folks here say, I don’t think it REALLY matters except in a lab, because there are far more variables than can be modeled effectively for what we’re all trying to do here!

This post was flagged by the community and is temporarily hidden.

You are getting some great replies here wayne! And since you’re talking theory, I’d expect to see your understand grow - assuming you assimilate the responses that differ from your POV.

"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."

I do not believe that number 1 is accurate in cases for anything other than high threshold motor units. The body will recruit whatever it needs and has available to get the job done. Fast rep speed or slow, it doesn’t matter. Note however that slow rep speed can be impacted by all fibers while fast reps, once the movement has been started, will only be impacted by fast twitch - that’s why the lifting work of a world record lifts is slower.

Number 2 is accurate in my view, it’s sparse but on point.

Wayne’s stuff:

The biceps even thou they only use a lower about of muscle fiber when repping slow would contract as a whole, this can easily be seen, just curl very slowly and look at your biceps not contract that much, now curl very far, and see the biceps contract very hard.

By the way I am into faster style repping, as I dont see much point in slower than 2/2.

The body will recruit whatever is needed to get the job done. Since fast reps start off as 0 speed reps, there will be some recruitment of slow twitch but as the movement speed increases, we’d expect to see less of them firing. So I believe you are correct with what you are saying, and it is of very little training consequence to them because they fire for only a moment.

I think people should train with a variety of rep speed but that’s an opinion so I’m not going to tell you that you are wrong for not doing it.

Slow lifting does nothing no matter what your goal is, there are studies about that. Lift fast and control the way down (± 3 seconds). Stop worrying about strict tempo. As fatigue sets in you won’t be able to lift to fast which is good, means the fibers are being recruited and fatigued, though if your trying to lift as fast as possible the neural and muscular effect is the same.

Take home lesson - lift as FAST as you CAN

First of all, I agree with everyone early on that basically said who gives a crap, lift the weight.

Secondly, however, isn’t the point of trying to move the weight fast (not necessarily translating into fast bar speed) that you will recruit more fast twitch muscle fibers - the ones most prone to growth?