Where does power come from? - Page 11

Internal muscle forces can be measured in a several ways in real people. One directly and one indirectly. In the laboratory they can be measured by attaching strain gauges to tendons, etc. This is rarely done to real people. :-) There are probably some other methods also. It is not my area of expertise. Another method used in cyclists looks at the end result of a bunch of muscles together, that would be by using force pedals which measure the amount and direction of the resultant force but it does not actually tell you what is going on in each muscle alone or together because it doesn't measure losses or inefficiencies that occur before the force is applied, as I mentioned before.

Anyhow, the direct method is to insert a small needle into the muscle and measure the change in internal pressure. This doesn't give an actual force but it correlates extremely well to actual forces. The other and more usual way is to measure EMG activation of the muscle using skin electrodes. The stronger the EMG signal the stronger the muscle contraction. Again, pretty good correlation and pretty easy to do in the laboratory.

There are a couple of places doing some studies on my product who are looking at this very thing (EMG activation and changes that occur in both runners and cyclists from using the product) right now.

like i said you need to read up on what mechanical advantage is and how it works... think pliers, think tweezers... if power goes up then yes absolutely energy expenditures go up, but not necessarilly muscle forces... there is more than two way about it... to increase power you can keep force the same and increase cadence, you can leave cadence alone and increase force or you can increase both cadence and force...

this is grade 7-8 physics... Work = Force through a distance and we cannot reduce the work/energy expenditure (conservation of energy and all that..)... but in all cases.. tweezers, pliers, and bicycle gearing you reduce the force necessary and apply it through a longer distance so in the end you are actually doing the same work even though you are applying a much reduced force.. at the same power in a smaller gear your feet travel a greater distance (more revs...each rev represents a distance equal to the circumferance of the circle that goes though the pedal axis) per unit time than in a higher gear... as i said this is grade 7-8 physics... if you don't understand this, good luck understanding the more complex stuff..

W = Fxd
100 = 100x1
100 = 50x2
100 = 25x4

- reduced force.. greater distance applied through --> same work, same energy

he's actually right.. force is not zero the force is tangental to the crank... displacement for one revolution is zero (effective work might be zero.. but not likely since you likley put more force into the down stroke than lifting?).. but the distance i travel for one revolution is the circumference of my crank arms... if i do a ride starting at home and end up at home (total displacement is zero) i still exerted some ave force for whatever distance i traveled over and accomplish whatever work or exerted whatever force at a velocity of whatever with an average power of whatever... same is true of a pedal rev... sure i end up where i started but my pedal still traveled the circumference of the circle that goes though my pedal axles and applied whatever force for the duration... the fact that the total displacement is zero is not really a factor.

Sorry, it goes beyond grade 7-8 physics. I wasn't taught physics til high school. Overschooled I guess.

Here is what you are missing. How much energy it takes to make the legs go around. Look at the pumping action of the thigh. It is accelerating up to a maximum speed then decelerating to zero the back to a maximum speed and back to zero twice a rotation it does this acceleration and deceleration. The thigh weighs perhaps 20 lbs. If you increase the cadence, not only does the thigh have to accelerate to a higher speed but it has less time to get there. The energy requirement to do so increases with the square of the cadence. The power required to do this increases with the cube of the cadence.

Now, where is this power coming from. Some will say it is coming from the other leg, one is going up while the other is going down. Well, that balances the potential energy but it doesn't balance the kinetic energy changes because both legs are accelerating and decelerating at the same time, just in opposite directions. Since this is a scalar and not vector number these equal but opposites do not cancel out but add together. It is not 7-8th grade physics but it is basic college physics.

Now, where is the energy coming from to do this? It can only come from one place, the muscles, the same muscles pushing the bike forward. Do the energy analysis. It is tedious but straight forward and then get back to me with what you find.

cheers.

Ok..

So we can measure each muscle and add them all up to get our strength(X). I would suspect there are a lot of muscles that are being used in each pedal stroke. We will then analyze the data and determine what muscle we should focus our training on. The only problem is we come back to the study of 1 vs 6000 reps.

Question. This is only the one time strength, not the 6000 rep strength, correct?


Why do you not have a study conducted to test FTP of Elite/CAT1/CAT2/etc. riders?

No, these measuring systems can be used for multiple repetitions. The entire ride could be analyzed and watch how the muscle fatiques over time or how the coordination changes with time. It could be done for one rep or 10000 reps or anything in between, whatever is enough to answer the question the investigator is asking.

I don't have the study you ask about FTP for various levels because I don't care about that. I am sure it exists. I just don't think it is particularly interesting. People are as strong as they have trained usually. My interest is in making people better whatever their current level and in figuring out how to best do that.

Frank

And how many electrodes would need to be attached while riding to do this test?

Would it be easier to measure power output for an hour?

I am sure you do not. The art of marketing.

It would take one electrode for each muscle being measured.

It would be easier to measure power for an hour but you don't learn as much. If you want to know about muscle activity you need to measure it.

Marketing what? Everyone cannot know everything. There are others here who can answer your question I am sure.

Right, this is what my question was. Since I am not am MD I do not know. How many muscles are used for one pedal stroke. How many muscles are in the leg alone, at least eight.

I do not care about the muscle strengh in my left pinky, I just want it to relax so it does not use as much energy.

Do a study, post a 40% increase, and hope nobody questions it.

And, failing miserably.

i *challenge* you to show me one person who has improved from average as you previously described (i.e., 2nd or 3rd cat cyclist) and gained this 'mythical' (or perhaps better described as b@ll@cks) 40% power. With their permission send me their Power Tap files to validate the improvement.

Ric

__________________
http://www.cyclecoach.com

ric,

I have failed miserably in getting you and some others to look at the potential of the device. I have not failed miserbly in getting some riders inestimably better than you or anyone you coach (Bettini, Backstedt, Steels, Leipheimer, etc. etc.) to believe in the system.

The Canadian National Cycling facilities at both Hamilton and Victoria BC use them a lot, we are trying to get some test data from them. I will be sure to let you know what they report to us. Or, why don't you contact them directly and ask them what they think? But, what would they know? Or, we just got the Belgian Olympic squad on them but what would they know? We expect to get some power data from them in time. That was part of the deal. You will have to wait like we will but I will be sure to let you know when we get it even though you will belittle it because I doubt we will increase their power 40%.

Here is some of what we do have. Other than the studies you know about all we have are reports of riders, none have sent us PT files. However some reports surely suggest 40% increases are possible in experienced cyclists. Josh Horowitz a CAT I who writes for pezcyclingnews has reported an increase in cruising power in one year from 225 to over 300 watts. That only calculates to a 33% increase I know but is the same order of magnitude we claim. You can contact him on your own and ask him about his improvement. that way I don't get in the way. Phil Holman reported an increase in top speed on the track from 35 to 38 mph and pursuit speed from 30 to 32 mph in 7 months, then he won a bronze at Worlds. That again calculates to only about a 27% improvement but that isn't bad to take someone to world class. Joe Skufka, a triathlete reported an increase in his speed during his monthly 12 mile TT test from 20 to 25 mph in six months. This is close to a doubling of his power in this time and the next year he increased to 27 mph and the next year to 28 mph.

You seem to think I guarantee that everyone will gain 40% in power. I do not. I just guarantee enough improvement that the customer will be happy with the purchase. Few return them. 40% improvement is very typical in one year. Some see more some see less.

Believe it or not. You choose NOT without the least little bit of investigation or curiosity because you think such improvement impossible. That is your choice. Ignore them at your competitive peril.

Frank

1st for clarity sake lets establish that we are talking about something different now...

- before we were talking about from basically from the pedal/bike side of the human machine interface... and the gross forces, power etc...
- now you want to talk about from the foot/leg side of the human machine interface... this is different.. kind of like first talking about the forces on the crank shaft of a car and gross power etc and then now you want to talk about the efficiencies and mechanics of inside the engine itself.

don't need to do any analysis.. higher cadences are obviously less efficient.. you need to lift you legs more times a second this is obvious... just like in a car the pistons and mechanics of the engine need to be lifted through gravity more, more friction etc.. but so what? in a car you put gas in the tank on a bike i eat more... the cost of maximizing power and just like with cars a rider probably has a power to rpm curve where at rpms x you achieve max sustainable power... let's reverse what you said... if lower cadences are so much better we'd all be riding at cadences of 10 rpms... in a race where you can refuel as much as need be do you want to be in the Ferrari or do you want to be in the Civic?

and where does the energy come from to make your legs change direction? when a train goes around a corner where does the energy come from to make it change direction? how about the tracks! cripes man your legs are strapped into pedals.. even a dead mans legs would go round and round if strapped him on a bike and you spun the cranks.. can you say inertia... how much muscular force is a dead man's legs exerting on the pedals?

all i have to say about your comment is so what? what the hell does this have to do with leg strength and do you actually have a point? what does this have to do with anything we are talking about? now that all your other points have been shown to be complete bs now you want to shift gears and talk about efficiency... which has nothing to do with what we were talking about before...

i'm out... i don't know how i got sucked into this unending vortex of the insane in the 1st place, but i know i'm getting out of it... sorry man, you're going to require more time than i have... either you are just unwilling or you are just unable to learn (there's a word for that...).. it's not ignorance you seem to be familiar with the formulas and the concepts, you just have no idea what they mean or how to apply them... it doesn't seem to matter how it's explained to you or how many times... you just don't get it..

Frank,

i really have no idea if your product works or not.. but i do know this, with 100% certainty from your comments you've made in this thread... you do not have a clue how or why is does or doesn't work... that's for sure!

I'll second that. The pattern is familiar now. Make a bold and ridiculous statement. When folks point out the error take a sideways step and either redefine a term or change the point of reference of the discussion. Keep dancing and you'll never get caught. Next we'll be arguing "force{}" as a nearly impossible to validate measure of intramuscular forces. If that doesn't work we'll move on to torque[] as in how Frank can get so many folks torqued up by making ridiculous claims and then dance around them with equally ridiculous misdirection.

Frank, you say you don't have a sales and marketing background. Too bad, kinda seems like you missed your calling. How about politics, your slide sideways debate style seems well suited to that profession as well. I don't care if the next five tour winners endorse your product. Your credibility has dropped to zero AFAIC.

Time to leave this thread to someone who cares........

Don't bail out now.
This thread will quickly catch the "It's killing me" thread in post count in no time.

I have to say this guy is persistent to say the least.
There's no way I could hang on that long with a forum discussion.