Impulse/force in pounds for the time frame

waynexk8

Please, for all to answer this one.

I was just wondering and thinking, ARE you adding “all” the force, I mean with the fast there are NOT just force being exerted by the muscles, there are HUGE forces on them, for say .1 of a second x the 6 reps = high forces on the muscle for maybe .6 of a second. Have you added these in ???

I mean the peak force from the transition from negative to positive, the [b]force on the muscle, NOT given out by the muscles ??? We call them the MMMTs {Momentary Maximum Muscle Tensions} these forces “ON” the muscles can be as high as 140%

Have you added these on ???

Lift 1,
You lift 80% of the ground, up 1m and then down 1m all in 1 second, .5/.5

Lift 2,
You start at the top, lower the weight down 1m, and then lift it back up 1m all in 1 second, .5/.5

On lift 2, on the transition from negative to positive, there will be huge force on the muscles and coming from the muscles.

Wayne

DaleSpam

Wayne, please focus. I am trying to help you learn some physics, that is what you came here for, right? Do you understand the force-time diagram. Do you see how the force is not constant, but that it varies over the lift? Do you graphically see what the impulse is?

DaleSpam

EMG measures electrical activity in the muscles, not force nor energy.

Yes.

No, you do 0 work over a rep regardless of if you do it fast or slow.

Peak power, yes, average power is 0.

OK, this can be interpreted more than one way, but at least one of them is correct.

While I am sure that you do fail faster with fast reps I don't think that your conclusions follow. Something is exhausting the muscle's ability to function, but why MUST it be the tension/time. Why couldn't it be the energy expenditure/time, or the oxygen debt, or ATP depletion, or lactate buildup, or temperature rise? I can think of lots of things that it could be, so the MUST just isn't true. Just because they fail faster does not imply that there is more tension/time.

Definitely.

Please get back on track, if you want to get anything out of this you need to actually challenge yourself mentally and learn a bit. Do you understand the previous graph, in particular, do you see what is meant by impulse?

douglis

O.K. Wayne....so you claim that all the above somehow prove that more force per unit of time is applied for the fast reps.
The least thing you should do is to try to prove with physics that those variables have the effect you claim.You obviously can't even try because you lack of even basic physics knowledge so you only have two options:

1)DaleSpam has the superhuman patience to help you learn step by step some basic physics.Shut up and read carefully what he writes.

2)A better and more time saving option.....read DaleSpam's last post and just accept it as a fact with no question asked.Especially this part:

waynexk8

Ok.

Yes, and thank you

Yesish.

Yes I understand that all too well.

Not really sure what you are getting at here ??? Are you saying/showing that my force will go up and up, as I am trying to accelerate the weight as much as I can, then as I have to decelerate it to stop for the transition in the repetitions, I have to use less force ??? If so yes I see that. However I think the area for the acceleration deceleration is a bit out. We found in a study that when using 81% the bar actually decelerated for 52% of the ROM. {range of motion} However, there was a flaw in that lift, as the concentric part of that lift, took 1.5 seconds. So I would say one of my lifts would have more an acceleration of 80% so I am using close to 100% force for 80% of .5 of a second.

Wayne

sophiecentaur

Wayne - you really can't bring yourself to believe that you are on a hiding to nothing and that what goes on in your arms is to do with your Muscles and their non-ideal behaviour. Muscles are not simple machines or springs and cannot be modeled as such. If they were, you would use no energy / force / strength / bananas if you just stood and held something stationary. You know that doesn't happen. Why keep ignoring this?

DaleSpam

OK, that doesn't sound very confident. Can you explain what makes you hesitate or a little unsure?

I am not getting at anything yet, I am just teaching you the meaning of the various important quantities. Are you unsure about what it means to have an area under a curved line, or is there something else bothering you about the area under the force v time diagram?

That is correct. The part where you are accelerating it up is the "peak" on the force v. time diagram, and the part where you are decelerating it is the "valley".

OK. So in the approximation I am using the bar is decelerating for 50% rather than 52%. We could certainly use more accurate representations of the motion, but if we did so the math would quickly get more complicated. I just used the simplest function that I thought was close. I am actually very glad to know that it is only ~2% off by that measure.

waynexk8

Will get back to the older questions.

Electrical muscle activity in the muscles is the force/strength they are using for the set time. Why/how could you think other, and what did you think it was ???

http://www.actabio.pwr.wroc.pl/Vol4No2/2.pdf

For the evaluation of muscle activities associated with force exertion the surface
electromyography method is well established. The amplitude of the EMG signal
quantitatively expresses muscle activity [16], [18], [32], [40] and has been used in
studies of various vocations to estimate muscle loads in tasks involving upper limbs [9],
[17], [38].
As maximum force exerted by the hand depends on upper limb location, for
musculoskeletal load assessment it is important to determine how the value of
maximum force changes in relation to upper limb location. Although studies which
considered this problem (as cited above) have been performed, taking into account
variety of upper limb locations, further research is still needed for normalisation
purposes.
The force which the muscle exerts as well as muscle tension expressed by the
amplitude of the EMG signal depend on muscle length (upper limb location) [3]. Also
the study of DUQUE, MASSET and MALCHAIRE [7] confirmed that differences in EMG
signal amplitude in the flexor carpi radialis muscle should occur according to wrist
flexion and extension, and the study of Wright (as cited in [6]) showed that the activity
of the long head of the biceps brachii depends on the arm abduction and arm rotation.
Muscle activity during force exertion can be spread up between muscle activity for
upper limb stabilisation in a defined upper limb location and activity connected with
the external force exertion. It should be expected that not only the component of
muscle activity, which is responsible for upper limb stabilisation, depends on upper
limb location but muscle activity associated with force exertion is influenced by upper
limb location as well. Therefore, it is also an interesting problem to see whether the
component of muscle activity, which is associated with handgrip force exertion, varies
according to upper limb location.

This is why I bought the EMG, to show what I call the total/overall muscle force or/and strength used in a set time will be different.

Let me try and prove my total/overall muscle force theory. Lift a very light weight up and down for 10 seconds, lift a very heavy weight up and down for 10 seconds, and the very heavy weight will need more total/overall force.

You use more energy in the fast,

You do more work in the fast.

As I move the weight 12m to the slow 2m, that’s more work done ??? Or are you saying, that if I move up, and then back down to the starting position I have done no work ??? Still don’t get that, as I thought work was force times the distance through which goes, thus 12m = more distance the force was used for than the 2m ???

So that’s more power in the fast.

Don’t get that sorry ??? Lets calculate how much power I would be used on both rep speeds. Distance weight 91 kg moved 1.85 M.

Determine the force we will need to figure out what the weight of the barbell is (W = mg = 91 kg x 9.81 m/s = 892 kg.m/s or 892 N). Now, if work is equal to Force x distance then, U = 892 N x 1.85 m = 1650 Nm.

We can calculate that lifting a 200 lb barbell overhead a distance of 1.85 m required 1650 J of work. You will notice that the time it took to lift the barbell was not taken into account.

Let us only add up the positive part of the lift.

The concept of power however, takes time into consideration. If for example, it took .5 seconds to complete the lift, then the power generated is 1650 J divided .5 s = 3300 J/s.

If it took 2 seconds to complete the lift, then the power generated is 1650 J divided 2 s = 825 J/s.

Slow set,
825 x 6 = 4950Joules.

Fast set,
3300 x 25 = 82500Joules

You move the weight 6 times further in the fast,

K.

You fail with these variables, 50% faster in the fast = there MUST be more tension on the muscles per unit of time to make them fail faster, = more tension = there must be more total/overall force if there is more tension as on failing faster.

Basically you fail faster because your muscles are working harder, and why would your muscles need to work harder ??? Because they were using more force/strength per unit of time. As the muscles don’t work harder because things are getting easier, but they work harder like machines or anything else, when the situation gets harder, and its far harder to accelerate a weight 6 times in 6 seconds, and to move a weight 12m to 2m in the same time frame.

It will be also energy expenditure/time, oxygen debt, ATP depletion, lactate build-up, and temperature rise, but the question is, “why” do you use more of these ??? I would think there can only be one answer, as the muscles are using more total/overall force, and having more total/overall force exerted on them, thus more tension on the muscles.

Question,
1,
I lift and fail at 24 seconds, I lift the weight 24 times and 48m, you lift the weight for 24 seconds, you lift the weight 4 times and 8m, if wanted you could lift the weight for 48 seconds, but you stop at 24 seconds, which muscle has worked the hardest ??? Which do I use more force.

2,
I lift and fail 50% faster, at 30 seconds, I then lift up a lighter weight and lift it for another 30 seconds. which muscle has worked the hardest ???

Which do I use more force, 1 or 2 ??? Which lifters muscles work the hardest ???

More speed, velocity and acceleration on the fast.

Please get back on track, if you want to get anything out of this you need to actually challenge yourself mentally and learn a bit. Do you understand the previous graph, in particular, do you see what is meant by impulse?[/QUOTE]

Right answered that one.

Wayne

DaleSpam

I have a PhD in biomedical engineering and did some coursework and research in functional electrical stimulation for neuro-prosthetic applications, so I know a thing or two about EMG, EEG, EKG, muscle recruitment, electrical stimulation, pacemakers, etc. Electrical muscle activity measures voltage changes due to the depolarization of the muscle cell membranes during the muscle's action potential, not the force exerted by the muscle.

Note, the key word "estimate". If you know the EMG and you know the tension v recruitment curve and you know the position of the limb and you know the force v tension curve for that position then you can use the EMG to make a good estimate as to what the force is. An estimate and a measurement are not the same thing. Force is measured with a force transducer, an EMG is a voltage transducer. The units of the EMG are μV, not N.

Before you can prove your total/overall muscle force theory you need to define it, otherwise there is no theory to prove or disprove. That is the purpose of teaching you about the standard physics concepts. I am hoping that as you learn what is meant by them you can express your concepts in the standard language, clearly define your theory, and then we can see the implications.

So, let's talk a little more about impulse and see if it has the properties that you expect for "total/overall muscle force".

Impulse has the property that if you exert twice the force for the same amount of time you have doubled your impulse. So, for example, if you exert 100 lbs for 10 s and I exert 50 lbs for 10 s you have exerted twice the impulse that I have. Does this agree with your concept of "total/overall muscle force"?

Impulse also has the property that if you exert the same force for twice as long you have doubled your impulse. So, for example if you exert 100 lbs for 10 s and I exert 100 lbs for 5 s you have exerted twice the impulse that I have. Does this also agree with your concept of "total/overall muscle force"?

douglis

Hi DaleSpam....if you have the time check the paragraph "2.1 Participants and experimental protocol" in this study.Do you think that the magnitude total muscle activation (TMA) can give a good estimation of the impulse?It's basically the integration of the EMG curve in respect of time.

It's interesting that the TMA per second is greater for the slow puh ups(in contast of what Wayne claims).For example if you check the tables 1 and 3 for the pectoralis major:
for the slow push ups the TMA is 3121.81 for 101.2 sec.(TMA/t=30.85)
while for the fast push ups the TMA is 2114.22 for 84.2 sec.(TMA/t=25.11)

waynexk8

Hi D. and all.

Are you trying to be sarcastic or something ??? I mean we are on a physics forum, I have all ready proved this, ITS UP TO YOU TO “TRY” AND DISPROVE IT, the cards are in my hands, the EMG states you wrong.

Don’t you understand, it’s up to you to try and prove me wrong and you right, WHAT PROOF AND EVIDENCE HAVE YOU ???

1,
EMG states fast,

I have the videos to prove it. All EMGs state this; it was MORE than obvious to me and most.

I mean walk up a 1 mile very steep hill with a pack on your back, then “try” and run up it as fast as you can. Which is the hardest on the muscles or/and which physiologically causes the greatest stimulus, as they are fast and slow actions causing far far far different stimulus even though they produce the same mechanical work, as computed by moving the same load through the same distance.


2,
You use more energy in the fast,

This has been known for a 100 years, I knew this 40 years ago. And this physics site showed and proved this to you.

3,
You do more work in the fast,

Work is the product of a force times the distance through which it acts, I move the weight 12m you move it 2m in the same time frame.

4,
So that’s more power in the fast,


Lets calculate how much power I would be used on both rep speeds. Distance weight 91 kg moved 1.85 M.

Determine the force we will need to figure out what the weight of the barbell is (W = mg = 91 kg x 9.81 m/s = 892 kg.m/s or 892 N). Now, if work is equal to Force x distance then, U = 892 N x 1.85 m = 1650 Nm.

We can calculate that lifting a 200 lb barbell overhead a distance of 1.85 m required 1650 J of work. You will notice that the time it took to lift the barbell was not taken into account.

Let us only add up the positive part of the lift.

The concept of power however, takes time into consideration. If for example, it took .5 seconds to complete the lift, then the power generated is 1650 J divided .5 s = 3300 J/s.

If it took 2 seconds to complete the lift, then the power generated is 1650 J divided 2 s = 825 J/s.

Slow set,
825 x 6 = 4950Joules.

Fast set,
3300 x 25 = 82500Joules

5,
You move the weight 6 times further in the fast,

I move the weight 12m you move the weight 2m

6,
You fail with these variables, 50% faster in the fast = there MUST be more tension on the muscles per unit of time to make them fail faster, = more tension = there must be more total/overall force if there is more tension as on failing faster.

There is a huge study proving this, have no time to find it right now, but you have seen it.

And there is my video.

http://www.youtube.com/watch?v=sbRVQ...1&feature=plcp


7,
More speed, velocity and acceleration on the fast.

Well if you don’t understand that ???


I am listening and answering, and all here are very intelligent and polite, and I thank them.

But no one is disproving what I say, like the 1 to 7 above, just try and say prove the EMG is wrong, but that’s not possible, as it’s a test that’s been done over and over by me, and 100,00 around the World, it’s one of the first tests people do when learning EMG, it’s a standard test.

Then there is you fail 50% faster, I mean that’s more obvious than 1 + 1 = 2, I mean you fail faster because the faster reps, like running to walking are far hider, they are harder because your putting more total/overall tension per unit of time on the muscles, that more tension = more total/overall force per unit of time on the muscles, or what do you think it means.

Why do you think your using more energy ??? Look, what happens when you run faster and faster, you use more and more force, vertical and horizontal and a little different, but basically the same, you have to use more force to run faster, and more force to rep the weight faster.

Will read his posts now.

Wayne

waynexk8

Could someone please answer this.


What forces do you think you have that can make up of balance out the higher propulsive forces of the fast in the studies ???

Let’s take the mean propulsive forces, slow 6.2mean in 10.9 seconds. Fast 45.3mean 2.8 seconds, now let’s divided the mean slow of 10.9 seconds by the fast 2.8 = 3.8, so now let’s divide the slow mean by 3.8 = 1.6.

Fast mean for 2.8 seconds = 45.3.

Slow mean for 2.8 seconds = 1.6.

The fast has nearny 3000% more mean propulsive force as in N's in the same time frame.

Please what forces have I left out that the slow has to make up or balance out these ???

http://www.jssm.org/vol7/n2/16/v7n2-16pdf.pdf

Wayne

waynexk8

Not sure what you mean here ??? I know its to do with my muscles, but I thought we were not debating this out on a machine repping the weight ???

I need to get back to your other post from a few days ago, sorry there.

Wayne

waynexk8

How do you work that out ??? What machine can lift say 80% up, and then lower it down using very little energy, and what energy is this ???

Wayne

Where and how does the machine get its energy back ??? It will be powered by say diesel or electricity, let’s say diesel, so it uses, let’s just say a half a pint of diesel to lift the weight, you tell me where and how the machine gets that diesel back ??? You know very well that when the half a pint of diesel is gone, has been used to lift the weight, you can “never” get it back.

And when it lowers the weight, it will have to use energy again, as in the diesel, a little less this time, but it has to use energy/diesel to move in any direction, as its using force, and this force is putting tension on the machine.

You and all here know physics far better than me, but I give you 7 real World practical points proving your theory does not fit, and as you know, a theory, is just a theory until you can prove it with a practical experiment, and I have proved it wrong and few times.

Just for now take the EMG, and the fact that you fail 50% faster.

Also, what have you proved ??? I see no equations, what you did say that there is no such thing as total/overall force in physics, yet the EMG reads out a higher average reading on the faster, and the EMG work with the equations of physics, they are put in the EMG.

I thought is was the physics job to do the theory, and when the practical proves this wrong, the physics needs to be looked at.

I do see what you mean, but what about my points, like the EMG, and the fact you fail faster, they can only mean one thing, the fast is putting more tension on the muscle, and the only way to put more tension on the muscle is by putting out more force, and taking more force on the muscles.

Wayne

waynexk8

Could anyone please answer this ???

I was just wondering and thinking, ARE you adding “all” the force, I mean with the fast there are NOT just force being exerted by the muscles, there are HUGE forces on them, for say .1 of a second x the 6 reps = high forces on the muscle for maybe .6 of a second. Have you added these in ???

I mean the peak force from the transition from negative to positive, the force on the muscle, NOT given out by the muscles ??? We call them the MMMTs {Momentary Maximum Muscle Tensions} these forces “ON” the muscles can be as high as 140%

Have you added these on ???

Lift 1,
You lift 80% of the ground, up 1m and then down 1m all in 1 second, .5/.5

Lift 2,
You start at the top, lower the weight down 1m, and then lift it back up 1m all in 1 second, .5/.5

On lift 2, on the transition from negative to positive, there will be huge force on the muscles and coming from the muscles.

Wayne

sophiecentaur

Here you go again - leaping in with both feet in the absence of knowledge. Do you know the difference between a Machine and an Engine? Of course a diesel engine has no energy return but a Machine, consisting of no more than a SPRING can lift and lower a weight without losing any energy at all (allowing for a minuscule amount, due to friction.

You have got it wrong when you say it is up to us to Disprove what you say. I'm afraid that it is up to you to Prove what you say because it goes against all known Physics. Just read any simple text book to find out the meanings and derivations the various terms that you are using with such abandon.

There is not a single statement from any of us which denies the fact that you feel more knackered and your muscles ache more when you are doing exercise faster. Our issue it that you are trying to 'explain' this in 'physics' terms that just don't apply. You have a gut feeling that it should be straightforward but you don't seem to realise just how muscles actually work. If you read what douglis tells you, instead of giving all those "but surely" - type responses then you might learn something.

Most people come on this forum in order to learn something. You have breezed in and you're trying to tell us all how we should be able to do something with the Physics that we understand but that you do not. Do you ever consider that you might just be plain wrong in this?

douglis

OMG you're really delusional.You don't have a clue about basic physics terms and you think have proved something!ALL your nonsesnse from 1-7 show NOTHING in terms of force.
I won't repeat them....it's a waste of time.
For your own good....quit your nonsense and just focus on DaleSpam's posts...he's really trying to help you.