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Calibrating Lifeline Chest Expander Cables - An Experiment

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#141 [url]

Jul 23 11 6:28 AM

Re: Email Correspondence From Lifeline's Kevin Dorsey

MrBrady wrote:
I'll tell you having a cable snap in a classroom situation did not make me happy! Thankfully it was only an arm slap, but she said it stung. This is NOT GOOD! Remember its was an essentially new cable, and very well cared for. BUT it was one of the 'plasticy' ones. I'm not a suing kind of man, but if she had been injured......

My personal opinion, they should take the whole system back to the drawing board. Get rid of the clever but awkward connection system, and use loops that are a proven performer.

I don't like the idea of having to go through the hassle of suing anyone either,  but if it ends up forcing a company to stop making and supplying inferior equipment that is dangerous, then I would do it if I had to.   

Any trainer carries a big responsibility for the safety of his/her trainees, and my respectful advice would be to stop using any Lifeline Chest Expanders before you have someone in your class that is seriously injured.  I would also contact Bobby straight away with this latest incident, so that at least he cant say that he wasn't told.  Hopefully he can then start asking his "engineers" a few pertinent questions. 

Gilstrap mentions that the handles are the main problem,  and I agree.  But I still believe that over-stretching is a significant factor,  one of my cables snapped in the middle.  There was no previous sign of wear. 

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#142 [url]

Jul 26 11 11:43 PM

Re: Email Correspondence From Lifeline's Kevin Dorsey

I wrote both Bobby and Kevin regarding the cable snap and the overall design of the Chest Expander. I received a very prompt reply from Kevin Dorsey.

This all bodes well! -

Hello Cole,

As a result of the strand pulling forum feedback, and Neal McKenzie, we are taking several steps to address the issues you and the members are describing.

Our Product Development and Quality Assurance Teams are finalizing the details on exactly how much length to add to the bands – we agree that this is a necessary step, as well as investigating the apparent material problem. Can you, if you haven’t already, send us the broken cable?

We will send you a replacement set at the longer length at no charge.

Also, the new Chest Expander design does feature a series of interchangeable looped cables.

Thank you,

Kevin Dorsey
Marketing Manager

“functional fitness since 1973”
www.LifelineUSA.com

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

From: Cole Dano
Sent: Monday, July 25, 2011 5:28 PM
To: Kevin Dorsey
Subject: Cable Breakage

Hello Kevin-

Recently i did a special class on Chest Expanders and had a almost unused cable break on one of my students.

The cable was a yellow, and it seemed to be of a different quality than the most cables. It had a kind of plasticly top layer. I'm not sure if thats a factor or not.

In any case the cable had not been used very much and was well cared for.

I'm sure you can understand this is a concern for use with the general public.

I have seen many members of the strandpulling forum i participate in also having cable breakages, often on new cables.

Since you relayed to the forum that Bobby is currently designing a new Chest Expander system, i hope you will consider going over to a loop system as they have proven much more reliable.

In the meantime, in addition to better quality control on the odd plasticy cable, i believe that the cables are just getting overstretched, and should be longer so they never are getting pulled to more than three times their original length.


Yours in Health-
Cole Dano

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#143 [url]

Jul 28 11 5:56 PM

Re: Email Correspondence From Lifeline's Kevin Dorsey

MrBrady wrote:
I wrote both Bobby and Kevin regarding the cable snap and the overall design of the Chest Expander. I received a very prompt reply from Kevin Dorsey.

This all bodes well!
Well you'll forgive me if I don't hold my breath,  I'm sure.   On the other hand,  if Lifeline makes a good loop or cable for its new Chest expanders, and advertises them correctly,  good for them.

  

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#144 [url]

Jul 28 11 6:03 PM

Re: Email Correspondence From Lifeline's Kevin Dorsey

Lifeline is shipping me a set of 19 inch cables to test. They also paid the expenses to ship my broken cable back to them so they can examine it.


I don't know what they did with you Macky but i think you should get in on this if you're not already involved.

Anyone with broken cables should correspond with Lifeline. As you can read in my email, i didn't request a new cable, Lifeline offered it to me.

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#145 [url]

Jul 29 11 6:40 AM

Re: Email Correspondence From Lifeline's Kevin Dorsey

MrBrady wrote:
Lifeline is shipping me a set of 19 inch cables to test. They also paid the expenses to ship my broken cable back to them so they can examine it.

I don't know what they did with you Macky but i think you should get in on this if you're not already involved.

Anyone with broken cables should correspond with Lifeline. As you can read in my email, i didn't request a new cable, Lifeline offered it to me.
Great that they are doing this for you MrBrady.  Mind you, you are quite a big customer.   I bought my Orange Lifeline set through John Woods site,  as they were the only ones to respond to my enquiries at the time.
When I first contacted Lifeline with my assertions that they were advertising grossly exaggerated pullweights,  I made it plain that I was not asking for a refund  ( possibly from or through John Woods ) but an explanation from Lifeline.  It's just comparatively recently that the second issue of cable quality and snapping strands has now appeared.
I've only ever bought a soft handles ( in my opinion, rubbish ) and Orange cable set.  As such, I'm happy to write them off,  without expecting any refund or other offers.  The moment my third and final band snaps,  the lot will be placed where all other rubbish goes,  into the trash can. 
If Lifeline ends up making a good set of chest expanders and posts correct pullweights on their Chest expander page,  then that's me finished with the matter,  as far as I'm concerned.   I may buy a set of the new Lifeline expanders sometime in the future,  but frankly I'm in no hurry after their performance of the last 17 months.      

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#146 [url]

Jul 29 11 7:37 AM

Re: Email Correspondence From Lifeline's Kevin Dorsey

I'm really not that big a customer Macky and that didn't weigh in this conversation at all.

I don't get why you'd go to all that effort and then when the ball is near the endzone give up, but its not my business either You did single handedly get them to change their product maybe that's enough.

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#147 [url]

Jul 30 11 6:36 AM

Re: Email Correspondence From Lifeline's Kevin Dorsey

MrBrady wrote:
I'm really not that big a customer Macky and that didn't weigh in this conversation at all.

I don't get why you'd go to all that effort and then when the ball is near the endzone give up, but its not my business either You did single handedly get them to change their product maybe that's enough.
I apologise if I gave the impression that Lifeline has given you preferential treatment only because of being a "big" customer.  Perhaps not as a distributor certainly,  but as a single customer,  you would probably have bought far more gear than the average strand-puller. I should have added that it would have no doubt been because of your willingness to commmunicate and try and work in with Lifeline and its problems in a constructive and helpful manner,  that they have included you in their testing process of their new cable lengths.
 
I first got into all this because of my observations on this Forum ( and on Youtube ) that many Lifeline owners were quoting vastly exaggerated pullweights in their training programs, and were disappointed later when they learned the truth.    Fatman and I conducted tests which proved beyond a shadow of a doubt that Lifeline's Chest expander advertising was 300% in excess of that truth.   These tests were repeated and confirmed later by neilkaz,  if my memory serves me correctly.
My first emails of enquiry were completely ignored until I specifically contacted Carrie Jensen.  Even after an email from her to Ray Rollins was ignored for a further three weeks until further prompting from me,  did I receive any answering email.  There have been no direct arguments at any time in the last 17 months or so, that my figures that I emailed to Ray Rollins were in error.   All I have had since then have been general statements about their cable measuring etc etc and which encompass and refer to their long cables,  and despite me repeating myself until I am blue in the face,  they have continued to give me these same irrelevant answers.  Lifeline have not even seen fit to lay aside 2 hours for one of its staff to check my ( and Fatman's and nielkaz' ) results and after taking most of the exaggerated figures from their old page last year,  have resurrected those same figures on their new page.
Those figures are blatantly fraudulent and have confused present owners and misled prospective owners into selections of cable colours which are 300% exaggerated.   
The issues of snapping bands,  quality control,  and cable lengths being too short have only cropped up in the last few months.  To their credit, Lifeline appear to be doing something about all that,  and I am confident that between you and I,  plus other reports of band failures on this Forum, we have been able to help bring about some positive changes in those directions.
However,  the original reason why I got into all this is still outstanding and ongoing.   Lifeline continues to ignore the basic fundamental issue of Chest expander advertised exaggerated cable pullweights that have/are causing confusion and outright disappointment,  and keeps puting out general and irrelevant statements in reply,  in other words, corporate-speak.
Even Kevin Dorsey's prompt responses ( as promised ) reflect the same mode of glossing over the one prime utterly simple issue.

I haven't given up MrBrady.  Lifeline are going to remove those BS and fraudulent cable pullweights from their Chest expander page,  or they will face a general complaint to the Federal Trade Commission,  for deliberately misleading the public and their customers.   Deliberate,  I say,  because there is no excuse for them not to know what they are doing,  after all the information I have given them over the last 17 months.  I have only posted a few of the latest emails between myself and Kevin Dorsey,  but there are a couple of earlier ones which I will shortly post up so you and the Forum members can see with your own eyes that I have put it to Lifeline in plain English,  that their Chest expander advertised cable pullweights are 300% in excess of what they actually are. 
I have already explained why I am doing this.  It's for the ordinary man in the street,  the dedicated trainer and strand puller who has paid hard cash in good faith to Lifeline for a product which they have not received,  and who base their choice of cables and their workout progress on blatantly misleading and fraudulent figures.      

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#148 [url]

Jul 30 11 8:04 AM

Re: Email Correspondence From Lifeline's Kevin Dorsey

7 June

Hello Mr. McKenzie,

 

I’ve received your email to our customer service team by way of forward earlier today.  I understand there have been various exchanges between you and other members of our team, and while I’m not entirely sure what was covered, I’ll do my best to try to help you.

 

Your first and fundamental question seems to be about our resistance cable rating system.  I have read through the discussion forum thread on “Calibrating Lifeline Chest Expander Cables” in its entirety and would first like to thank you and the other members of the forum for your commitment to and enthusiasm for strand pulling, and the general appreciation you all appear to have for the fine quality and function our particular models offer.

 

I’d also like to offer the context that LifelineUSA offers, through various brands and affiliations, over 90 systems that utilize premium, dipped rubber as the resistance delivering engine or mechanism.  We sell these systems to mass and niche markets around the globe, and have done so for some thirty-three years.  The cable rating system we employ is a universal, or comprehensive approach to qualifying the forces our cable components create.  We use both a poundage and color scheme to differentiate the cable components of these various systems to help our customers decide which cables suit their various needs.  I’ll also point out that the bands we offer range in length from 6 inches to 25 feet.  (Most of these options are no longer available through our own direct channels but are available in gyms, schools, shops, websites and catalogs around the world.) 

 The poundage rating is calculated and tested based on the cable component itself.  While I’m not a physicist, I believe the discrepancy between the forces you measure and the forces we list comes down to the method we use to determine the forces the cables produce.  Our cable rating system was developed in the 1970’s by an affiliate of the University of Wisconsin who was asked to describe the cable component force acting on the body of a person standing on the center of a 5’ cable and stretching it with both hands.  The force in the cable (also the force acting on the body), as it was explained to me, is the sum of the forces measured at the handles multiplied by two, to account for the equal and opposite force acting on the foot of the person stretching the cable.

 

The universal use of this poundage rating system in all our cable products is made possible by the inherent properties of elastic resistance, because any length of cable, except those that are less than 10 inches, will generate the same elastic force at a ratio of stretch tied to its original or ‘resting’ length.  We test this ratio and hold our manufacturing partners to it on a batch to batch basis, because it does vary.  We know that the larger cables do vary more than the lighter ones, but are generally within 10% of the specified rating. 
As this relates to our Chest Expanders, the force a 50lb cable component creates at 3x its resting length is 50lbs.  If you measure one handle, it will read 25lbs 10%.  We have archives of batch testing information that substantiates this claim.  (I’d further like to clarify that in addition to the cable forces, we test and specify the inner and outer diameters of the cables to 1/1000 of an inch.  On that product, we also test the chemical makeup of the rubber itself (to measure latex content and water soluble protein content).  We also test and specify the quality of the webbing, sewing thread and foam grips, as well as the chemical, and toughness properties of the plastics that makeup the cable pockets.)  To understand the 50lb claim, you must account for the equal and opposing force the cable is generating on both ends.  If you’d like to measure this another way, simply utilize two load cells – one on each end and sum their readings.  The point of measurement, should you like to conduct this test, is the upper edge of the tapered cable plug that is inserted into the cables.
I understand that the point you’re asserting is that the rating system is confusing and can lead to improper cable selection by patrons such as yourself.  In the four years I’ve been with LifelineUSA, I am aware of only a handful of customer confusion issues that have resulted in an inquiry to our offices, across all the cable systems we manufacture and market.  While we take every customer satisfaction issue extremely seriously, and each incident does trigger internal review of each situation, we have literally sold millions of bands in the same timeframe.  I was actually part of the team that took and tested your questions about the cable ratings last November.  It was the decision of our former CEO, Barbara Koren, to do our best to deliver satisfactory explanations to you at that time.  You likely received the cable force measurement PDF that was developed as a direct result of your inquiries, and is now posted on our FAQ page.  Since the development of that document, I believe we’ve provided it to four other patrons, along with an offer to exchange the cables they had purchased for heavier ones, at no additional charge
While we maintain that our rating system is valid, for all the reasons I’ve attempted to outline in the message, we have still to resolve the important matter of your customer satisfaction.  This fitness company and the dedicated team we have working here, really do care deeply about our customers and the way our tools facilitate success in their athletic endeavors.  We feel that the effort we put into product development and improvement is a monument to that commitment.  As I mentioned in the forum post, Bobby Hinds himself is developing a new Chest Expander that will revolutionize the category with an innovative new system.
I’d like to keep this dialogue open with you until we reach a conclusion you deem satisfactory, and hope to earn your loyalty and future business.

 

Best regards,
Kevin Dorsey

8 June

 
Hi Kevin,
 
First of all I would like to thank you for your prompt reply and consideration. 
Secondly,  I want to say that it has not been for my satisfaction ( whether as a customer or merely to prove a point ) that I have carried on trying to make Lifeline see the truth of what I am saying about their false chest expander pullweights on their page.
Thirdly,  I am not interested,  nor have I ever been, in Lifeline's Long cables or any other product, or manufacturing methods,  except the Chest expanders and their advertised pullweights, in this context.
 
Now I would respectfully ask you to pay attention to what I'm saying ( I've said it so many times before ) so that you have a clear idea of what exactly I am on about.
Your Chest expander cables are approx only ONE THIRD of your advertised pullweights on your Chest expander page.

The FAQ page you have referred to me and the Forum, is for Long Cables ,  not chest expander cables.  Is that clear ?
Those pullweights may well be accurate for the long cables but for 16" chest expander cables, they are not.  The whole FAQ page is describing the long cables.  How can you possibly compare them with 16" chest expander cables ?
This is part of the confusion that Lifeline staff are labouring under,  and the affiliate from the University that developed the cable rating system was working on the LONG cables.  Even the list on the FAQ page is for Long cables,  which is perfectly obvious because the list on your FAQ page includes a 100lb Black cable,  which is NOT in the Chest expander cable range.

Now that you may be gaining a glimmer of understanding about what I'm saying,  we will take a simple case of basic physics.
If you anchor one end of a 16" chest expander cable and pull out to 32" length ( twice the resting length,  which is what I'm repeatedly told by Lifeline is the determining pullweight of their chest expander cables, not Long cables at 3X )  and then measure with some sort of accurate scale the poundage pullweight,  ( say it;s 10lbs ) then that cable will have 10lbs of force exerted on the stopped end,  and the cable will have 10lbs of tension on it.    If it had anything else the scale would read differently.   Simple.

If you read my test figures for the Orange cables that I bought from John Wood's site,  you would have seen this.....
O1 @ 32" =  15.5lbs  average
O2 @ 32" =  15.8lbs       "
O3 @ 32" =  15.6lbs       "

O1 at full stretch =  28lbs average
O2 at full stretch =  27lbs     "         
O3 at full stretch =  26.6lbs  "        

That is your single ( each ) cable ratings for your Orange Chest expander cables.  Period.   Even at full arm stretch,  your  50lb Orange rating is vastly exaggerated.
That has caused confusion,  debate,  and disappointment for years all over the world, ( there is ample evidence on the Forum and on Youtube and other sites ) and I am asking you if someone or yourself buy a simple suitcase or spring scale and actually do what I've asked Lifeline to do for the last 15+ months,  check my results, then you will see why your pullweights for single ( each ) chest expander cables are potentially fraudulent.  Never mind all the university clever stuff which has only served to confuse everyone at Lifeline,  at least as far as Chest expander cables are concerned.
Take 27 scale readings, three for each chest expander colour, so that a reasonable consistent pullweight may be determined. The average of the three pullweight readings for each colour cable is posted on your Chest expander page. Up to 10% either way is also acceptable for a stretchy type material, let's be reasonable. 
 
I now repeat what I have asked Lifeline to do before, and add some alternatives, in the interest of Lifeline's integrity :-
1.  If you must keep the pullweights on the Chest expander page as they are,  change the words "each" for "all three cables".  As they are only one third the advertised pullweight,  this would be sufficient to reflect the truth.
2.  Post genuine pullweights for the range of single cables.
3.  Remove the pullweights altogether and put the colours back on your new page.  There is a wide consensus here in the Forum that the pullweights,  even if they are correct,  are meaningless because they only reflect twice the resting cable length stretch.  Even if "full-stretch" pullweights were posted,  everyone's arm span is different.  Many trainers have abandoned Lifelines pullweights in frustration and now base their workouts on colours.   " Moving from three Oranges to two Oranges and one Red " for example.
This is a far better way to advertise your Chest expander cable range.  Let's face it,  everyone knows that pulling out three Blues is a "rite of passage" into the realm of the Strongman,  whereas your previous adverts citing three blues as having 270lbs of resistance is just pure nonsense.
I hope I have made things crystal clear to you, and if you need further explanations don't hesitate to ask me.  Now that I've shown you the correct way to calibrate Lifeline's range of Chest Expander cables,  unless a staff member can PROVE that I am in error,  I expect to see one of my three suggestions acted on within two weeks, please.  It would take a half a day at the most to measure Lifeline's range of Chest expander cables,  and post the true pullweights onto your new Chest expander page.
 
Yours sincerely
Neal McKenzie

Can I have possibly put it more plainly than that ? 
There were some interim emails where Kevin informed me he was out of town,  which was good because dialogue was being maintained, instead of just deafening silence,  but the official reply on the matter came through on 20 July.  I've already posted the full email on this thread,  but these are the relevant paragraphs for this issue.   More generalisations instead of specifically addressing what I've been emailing Lifeline for 17 months for.  What can I now do to make Lifeline address what is being brought to their notice,  other than contemplating involving  the FTC and bringing a complaint against Lifeline for exaggerated and misleading advertising ?  Any suggestions ?

We cannot, unfortunately, do away with our cable rating system as this is a keystone system we use to help our wide array of customers decide which bands are right for them.  In general, the system seems to work.  We sell well over a million bands a year, Chest Expanders being a small part, and the feedback is overwhelmingly positive.
I understand the frustration of those on the Strand-pulling forum, but as a company we do our very best to offer great value and information to help our customers navigate our product lines.  How would you help a new strand-puller decide which bands to start with?  I could potentially incorporate this feedback into a modification of our Chest Expander website product description.

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#149 [url]

Jul 30 11 4:05 PM

Below is a quote from Kevin Dorsey of Lifeline USA in correspondence with our Macky -

As this relates to our Chest Expanders, the force a 50lb cable component creates at 3x its resting length is 50lbs.  If you measure one handle, it will read 25lbs 10%.  We have archives of batch testing information that substantiates this claim.  (I’d further like to clarify that in addition to the cable forces, we test and specify the inner and outer diameters of the cables to 1/1000 of an inch.  On that product, we also test the chemical makeup of the rubber itself (to measure latex content and water soluble protein content).  We also test and specify the quality of the webbing, sewing thread and foam grips, as well as the chemical, and toughness properties of the plastics that makeup the cable pockets.)  To understand the 50lb claim, you must account for the equal and opposing force the cable is generating on both ends.  If you’d like to measure this another way, simply utilize two load cells – one on each end and sum their readings.  The point of measurement, should you like to conduct this test, is the upper edge of the tapered cable plug that is inserted into the cables.


This takes us back to what i was thinking earlier. The scale attached to the end of the cable does indeed measure the tension at the end of the cable. Each hand is exerting that amount of force against that tension.

This much we all agree on! Beyond this we have to define what we are measuring. If we want we can say pull-weight is equal to the tension or we can say that since each hand is pulling the force of the tension, the pull-weight is equal to the total force being used or twice the tension.

I think Lifeline has every right to think of it this second way for their purposes. In fact i think that's the best way to think of it.

So if we accept that the total force definition is ok and then we add the change of length from 2x to 3x we do indeed find theoretically LifeLine USAs measurements correspond with those found on the forum.

This morning i decided to test an orange cable. Since i don't have a hand scale is simply attached 25lbs to the end of the cable and found it to have stretched to 3x it length.

In my earlier post i was thinking in terms of cable tension and did mess that up, but reference to a physics text set me straight. If we think in terms of total force at the handles everything is fine. 

The second source of confusion was Lifeline's own drawing, but they assume that the rope under the feet is the same as the rope attached to a wall. They only measure the force at the handles, which is actually the same as in strand-pulling.

With this new information, i am completely satisfied with Lifeline's ratings.

The only outstanding issue being that they do mix pull lengths on the site, sometimes saying 2x and sometimes 3x. 

Last Edited By: MrBrady Jul 30 11 6:23 PM. Edited 1 time.

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#150 [url]

Jul 30 11 4:08 PM

Re: Email Correspondence From Lifeline's Kevin Dorsey

Macky, Kevin's explanation is very through and complete and explains the situation perfectly. 

I wanted to keep the measurement problem together in the old thread so if you want to check here...

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#151 [url]

Jul 30 11 6:49 PM

With all due respect MrBrady,  Lifeline's reasoning as regarding the Chest Expander cables is fundamentally flawed.   They have done what I suspected some posts ago,  confused their Long Cable calculations and measurements with the Short Chest expander cables, citing dimensions and process which do NOT belong to Chest expander cables, by their own disclosures.  I have said many times that I am not talking or interested in Lifeline's Long cables.

 Our cable rating system was developed in the 1970’s by an affiliate of the University of Wisconsin who was asked to describe the cable component force acting on the body of a person standing on the center of a 5’ cable and stretching it with both hands.  The force in the cable (also the force acting on the body), as it was explained to me, is the sum of the forces measured at the handles multiplied by two, to account for the equal and opposite force acting on the foot of the person stretching the cable.

 Since when do you calibrate a 16" cable 2X stretched in a straight line by standing in the centre of a 5' cable,  presumably grasping both ends,  then taking a measurement from there ?
 Next,  the paragraph that you posted mentions 3X its resting length.  Lifeline have repeatedly stated that their Chest Expander cables are calibrated at 2X their resting length.  If they had actually measured their Chest expander cables they would quickly see that their Chest expander cables differ from their advertising.  They have in fact NEVER measured their Chest expander cables in the manner that they say,  they have simply transferred their Long cable measurements per colour to the Chest expander page.  This is simply a reliance on some academic's results 30+ years ago( which may well be correct for Long cables ) and it amazes me that in 17 months they have not seen fit ( a multi-million-dollar company ) to spend $40 on a suitcase scale and check my figures,  preferring instead to firstly ignore research from outside their company,  then engage in hours of confused figures and explanations of process which have no relevance whatsoever to the exaggerated advertising issue. 

"So if we accept that the total force definition is ok and then we add the change of length from 2x to 3x we do indeed find theoretically LifeLine USAs measurements correspond with those found on the forum."  

Sorry, quite wrong.  My full arm stretch handle to handle is 64".  Taking 6" off each end for the handles we end up with 52" stretch on a 16" cable.  Given that only about 13.5" of the cable does the stretching,  that is well in excess of 3X it's resting length. Even more than 3X 16" total length.  Even then the Orange cables only measured approx 27 lbs each at this stretch,  about 54% of stated and advertised pullweight of 50lb.  How can their measurements correspond with those found on this forum ?

"This morning i decided to test an orange cable. Since i don't have a hand scale is simply attached 25lbs to the end of the cable and found it to have stretched to 3x it length."

I presume it was an Orange chest expander cable that you tested here MrBrady.  Given Lifeline's own parameters,  the 25lbs weight should not have even stretched the cable 2X,  never mind 3X.   It should take a 50lb weight to stretch the Orange cable 2X if their posted advertised pullweights are correct.  Remember pullweight is pullweight,  whether by a barbell plate or by muscular force.  A cable therefore with a 50lb plate hanging off one end with the other attached to a scale will have 50lbs tension on it,  and the scale at the other end of the plate will register 50lbs.  This is a basic fundamental fact of physics that can be proven both by experiment and by careful deduction.   We are not talking about standing in the centre of a 5' cable,  we are measuring a 16" cable in a straight-line stretch.  

Lifeline are totally confused when it comes to the calibrations of their Chest expander cables.  They have also NEVER done any Chest expander ( 16" ) measurements,  otherwise we wouldn't keep being subjected to this confused corporate line they continue to indulge in.  All it takes is someone in Lifeline to stop talking,  get off their butt,  and do what I have suggested, actually measure their Chest expander cables, and confirm what at least three members of this forum have proved 17 months ago.

Is that asking too much ?    So far it certainly is.

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#152 [url]

Jul 30 11 8:20 PM

Macky there is no confusion, they are essentially the same measurements. The key is realizing that what is being looked at is the force exerted at each handle. Whether the cable is straight or held under the feet doesn't actually affect this.

Our cable rating system was developed in the 1970’s by an affiliate of the University of Wisconsin who was asked to describe the cable component force acting on the body of a person standing on the center of a 5’ cable and stretching it with both hands.  The force in the cable (also the force acting on the body), as it was explained to me, is the sum of the forces measured at the handles multiplied by two, to account for the equal and opposite force acting on the foot of the person stretching the cable.

Here Kevin is making the same mistake that i made in my earlier post. TENSION is the force exerted through the cable. For our purposes it will always be the force on ONE handle. We actually agreed on this earlier. The tension the a measure of the weight the cable is supporting.

Let's do a little experiment:

Hang a cable from a hook on the ceiling and attach 25lbs to the end. As we already agreed, and i confirmed via reference to my university physics text,  the cable will have 25 lbs of Tension on it.

Now, if i take the cable off the hook and hold it with my arm, i'm obviously holding 25 lbs. (plus the weight of the cable and handles, but we can assume they are light and ignore that for this discussion)

Ok so i'm holding 25lbs with one arm, now i take the weight off the end and with my free hand stretch the cable to the same length it was with the 25lbs hanging from it.

Then that arm is now exerting 25 lbs of force as well. Its the same force the weights were exerting. Since we already measured the force in the upper arm at 25 lbs that means BOTH arms are exerting 25 lbs of force for a total exertion of 50 lbs.

If i decide to step on the band and pull it to the exact same length each hand will still see 25 lbs of force, it really doesn't matter. (if you get really picky you could subtract the length of cable underfoot)

So when you realize that they are measuring force in each handle,  everything checks out.

Yes they do make the statement that the stretch length is 2x in many places, that needs to be corrected, but with the 3x stretch my quick measurement confirms what Lifeline states.

You can disagree and think they should measure tension, but to claim they are misrepresenting the facts is not the case. Depending on your viewpoint, you can think they should measure tension instead, but that doesn't make them liars. I personally think the force on each handle is exactly what we are interested in.

So really the only thing that needs fixing on Lifeline's site are the places where it says 2x. 

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#153 [url]

Jul 30 11 8:43 PM

Here's an email from Ray Rollins from last year  ( 9 March ) which shows exactly the same confusion as Kevin's emails,  between Lifeline's Long cables and their Short Chest expander cables.
Can anybody tell me what a 5' cable with two handles and the cable going through a door attachment has to do with a 16" Chest expander cable ? There is no R10 Chest expander cable that he mentions here, so what is Ray Rollins waffling on about ?  The R10 is the 100lb Black of the Long cables on the FAQ page, which describes the testing methods and the list of Long cables.  Nothing to do with Chest expander cables.
Note also the mention of the automated tensile strength tester ( the same as what Bobby Hinds mentioned only a short time ago ).  Seems to me that nobody in Lifeline knows how to design and build one,  much less know what a simple spring or suitcase scale is. 
That of course is not surprising,  given that Lifeline does not know the difference between their 5' and a 16" cables, despite being told repeatedly.

Hi Neil,

Sorry for the delay.  We are a company where each employee has to wear many hats.  My job is changing more into Quality Control.  I’m in the process of developing (with outside resources) an automated cable tensile strength tester that we will be using to validate the existing data.  Currently the stated poundage comes from using a 5’ cable with two handles and the cable going through a door attachment.  The result of this is having 2 - 2 ½’cables with two handles.  Taking a R10 and stretching 2 ½ times its resting length, 50 lbs per handle will be generated.  Cable is not a finite product like dumbbells.  There are variances in the inside diameter, outside diameter, and chemical makeup which may affect the results.  We try to control those as much as possible; which is why we are developing an automated tester.  I hope this answers your questions.  I will look into the stated poundage on the chest expander to make sure it is correct.  If you have any more questions, please ask.

 

Cheers, 
  Ray Rollins
Product & Production Engineering/QC
Lifeline

June 13 

Dear Ray
 
I forward you my emails to refresh your memory of my concerns about your company's false advertising and the reasons why.
I note that 3 months later the situation has not been rectified and is still causing confusion among otherwise satisfied Lifeline customers everywhere.
 
I post you the page URL and the offending paragraphs and ask that you deal with them immediately, as by the growing evidence in the submissions to the Strandpulling Forum I belong to prove that confusion over Lifeline's cable pullweights is ongoing.
 
Yours sincerely
Neal McKenzie
 
 
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Shortly after this most of the false pullweights were removed from Lifeline's old chest expander page.  Why have they found their way back onto the new page ?   The confusion between 16" cables and Long cables has never been cleared up,  that's why.

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#154 [url]

Jul 30 11 8:55 PM

Macky cable doesn't care if its bent in the middle. It just a matter of how much it is stretched from rest length. Read my previous post.

It is interesting that at that time Ray gave a figure of 2.5x stretch.

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#155 [url]

Jul 30 11 9:23 PM

You have confused the issue and contradicted your own previous paragraphs,  I'm sorry MrBrady.
"Then that arm is now exerting 25 lbs of force as well. Its the same force the weights were exerting. Since we already measured the force in the upper arm at 25 lbs that means BOTH arms are exerting 25 lbs of force for a total exertion of 50 lbs."

What are you talking about when you say there is a total exertion of 50lbs ?  We are talking about posted cable pullweights ( tension ) ratings not the force that one has to apply to a cable in order to stretch it to 25lbs tension with two arms. 
If there was a scale inserted in the cable being stretched, and the handle,  when the scale read 25lbs,  then there would be 25lbs force exerted on each end,  whether they were being both stretched apart, or one end of the cable was fixed. Therefore whether you were using both arms to put 25lbs of tension on the cable,  or only using one arm with the other end of the cable firmly fixed,  the moment the scale read 25lbs and the cable was stretched to 2X its resting length,  then that is the rated pullweight.
The problem is that you and Lifeline also cant seem to get away from the FAQ page which describes the method and list of measurements for the Long cables.  If you take another look at the FAQ page you will see a couple of diagrams showing a person standing on a foot scale and puting 50lbs of force on the scale by stretching upwards two handles.  Because both handles are pushing up in the same direction,  this effectively places the foot scale at one end of a straight line pull, and the handles at the other.  THEN the 50lbs tension will be shared by the two handles at 25lbs each.

That is not the case when you set out to measure a 16" cable at 2X and post a rating for that cable. That 16" is not folded around any object and then the angle of pull is altered.  It's pulled from each end ( or anchored ) in a straight line, directly opposite each end.   

And that is precisely where a lot of the confusion has been.  I'm surprised that the "engineers" have not picked up on that,  which is why I've remarked before that they are only there to eat their lunch and pick their pay up.  Even more amazing,  nobody in Lifeline seems to understand plain English or take the time to check my assertions. 

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#156 [url]

Jul 30 11 9:51 PM

Oh Macky - you are simply wrong here. I'm really sorry, i don't know how to explain it any better.

The scale will read 50 lbs, but the diagram doesn't show that the feet are also pushing back at 50 lbs. It isn't relevant either so it doesn't need to. The total exertion the man is using is 100 lbs, but the interest here is what is at the handles.

I do have a degree in physics and have worked as an engineer, maybe that makes me another lacky. I'm not paid by Lifeline, i just find this an interesting problem.

Like i said they are NOT measuring tension, they are measuring total force at the handles, which is quite smart because then the ratings do work for any cable situation, once you understand the idea. Its their choice to do it that way, its not wrong, its just the way they choose to do it. However the results will be consistent across the line.

In the case of their picture the force at the handles is ALSO the tension, because they don't count the force at the feet. In a strand pull that's the difference, so it winds up being 2x the tension, but the force at both handles is the same in either case.


I'm not contradicting anything i said before. I was earlier corrected by you on the matter of tension, when i claimed it was twice the pull of the weight. Now you are saying its twice the pull.

If i am holding the band with weight attached, i'm holding that weight. I'm exerting that much force against the weight to hold it. If i take the weight away, and use my free hand it has to push as much as the weight was, to the other hand it is still holding as much as before, so the hands together are now doing twice a much. Its Newton - for every force there is an equal and opposite force.

The only problem is why the degree of stretch is changing, from 2x to 2.5x to 3x.

Last Edited By: MrBrady Jul 30 11 10:03 PM. Edited 2 times.

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#158 [url]

Jul 31 11 8:37 AM

MrBrady wrote:
Oh Macky - you are simply wrong here. I'm really sorry, i don't know how to explain it any better.

The scale will read 50 lbs, but the diagram doesn't show that the feet are also pushing back at 50 lbs. It isn't relevant either so it doesn't need to. The total exertion the man is using is 100 lbs, but the interest here is what is at the handles.

I do have a degree in physics and have worked as an engineer, maybe that makes me another lacky. I'm not paid by Lifeline, i just find this an interesting problem.

Like i said they are NOT measuring tension, they are measuring total force at the handles, which is quite smart because then the ratings do work for any cable situation, once you understand the idea. Its their choice to do it that way, its not wrong, its just the way they choose to do it. However the results will be consistent across the line.

In the case of their picture the force at the handles is ALSO the tension, because they don't count the force at the feet. In a strand pull that's the difference, so it winds up being 2x the tension, but the force at both handles is the same in either case.

I'm not contradicting anything i said before. I was earlier corrected by you on the matter of tension, when i claimed it was twice the pull of the weight. Now you are saying its twice the pull.

If i am holding the band with weight attached, i'm holding that weight. I'm exerting that much force against the weight to hold it. If i take the weight away, and use my free hand it has to push as much as the weight was, to the other hand it is still holding as much as before, so the hands together are now doing twice a much. Its Newton - for every force there is an equal and opposite force.

The only problem is why the degree of stretch is changing, from 2x to 2.5x to 3x.

My good friend,  let's go back to the basics of my original assertion and firstly deal with 16" chest expander cables, ok ? This is my prime and only issue, as by now the other issues appear to be getting taken care of,  with your able help I might add.

It's important that we have this interesting and friendly debate,  and get things clear in your mind because you are dealing with Lifeline more closely now,  and if you end up agreeing with their confused and erroneous Chest expander information,  you will effectively give them an outside ( customer ) endorsement of their ratings,  particularly since you have disclosed that you have a degree in physics, which they will undoubtedly seize on if they are monitoring these discussions on this Forum.

1.  Anchor one end of the said 16" cable and using a scale,  stretch out to twice its resting length.   How that stretch is applied, or whether the other end is also being pulled instead of anchored has no relevance to the outcome.  The instant the cable reaches 2X its resting length,  the poundage registering on the scale is the rated pullweight, and that figure should be reflected on the Chest expander page as a bona fide,  no BS,  rating for that particular coloured cable.  Are we agreed on this ?  I have proven that even at full arm stretch,  Lifeline's advertised pullweights are grossly exaggerated.  That should have been the end of the matter,  make some new measurements and post them up on the chest expander page.

2. However, since you and Lifeline both insist on making references to the methods and poundages contained in the FAQ page for their Long cables and relating them back to the Chest expander cables ( thereby utterly and completely confusing the issue )  let's get a few things straight right there and then.
First of all, the total exertion the man is using will not be 100lbs as you say.  Otherwise the scale that he is standing on ( the other end of the pull ) would register 100lbs, apart from the addition of his own weight of course.

Have a look at the lower diagram on the FAQ page showing the cable stretched around a single pivot point instead of a foot scale.  That reflects a truer picture of the stretch length of 3X than the "standing on the scale" pictures.
Taking that it is an Orange cable being measured, it is therefore 50lbs of tension registering on the scale because the scale is hooked around both handles. 
That is Lifeline' rating for the Long Orange cable. 
Because both handles are pulling in the same direction and held together by the scale,  they are effectively one end of a straight line stretch,  the pivot hook is the other end.  50lbs at each end. 50lbs TOTAL stretch for the TWO cable lengths.  If it was not so,  the scale would register something different.  
If we obtain another scale and separate the handles, and measure them with each scale,  there will be 25lbs of tension on each scale. There will still be 50lbs of tension on the pivot hook.  I think that is well understood.
But the cable tension overall will not be actually 50lbs,  as is rated,  it will be ( and is ) 25lbs when stretched to 3X its resting length.

Therefore you are correct when you say Lifeline are not measuring cable tension,  they are combining the total force at the handles at 25lbs each = 50lbs. Once this is clearly understood,  then the diagrams with the guy standing on the scale being compared to the diagrams showing him lifting the same barbell weight, become straight forward and the ratings for the Long cables become clear.  

Like I have often said in my posts,  Lifeline's Long cable ratings may well be correct,  for all I know.   Now that I have been forced to spend time on the FAQ page determining what is true and what is not,  they are in fact correct by way of the interpretation that has been applied.

This interpretation is not smart at all from a customer's point of view.  The poundages have been listed next to the cable colours as a 3X stretch rating for that colour.  Even the diagrams which become clear after some considerable thought do not help the situation,  because as we both know,  there wouldn't be all this debate and confusion if the page was more clearly presented.  Most trainers brousing the Net for cable equipment will not spend time having to work out how Lifeline has determined its "clever" parameters.  They will simply glance at the cable ratings list and take them as bona fide cable pullweights,  basing their purchases and subsequent workouts on these ratings.  There is plenty of evidence around this forum and on Youtube to support what I have just said.

Worse still,  this confusion has spilled over to the Chest expander cables, which instead of actually being measured properly,  as Lifeline asserts,  have been given the same ratings as the Long cables,  on the Chest expander page.  This has resulted in confused and erroneous responses to my original assertion that Lifeline's Chest expander cables are advertised exaggerated by 300%.

Plain simple information which I have spent 17 months supplying to Lifeline has been completely ignored and the same old "party line" responses have been issued in answer to my ( and others ) test results for their Chest expander cables.  What really amazes me is how long they can keep this corporate dogma up,  while not even spending 30 minutes to check whether I am right or not.

The only reason why I am not taking them to the FTC at the moment is because I am waiting for their new Chest expander cable lengths to be tested and rated.
I would hope that they test them properly,  and dont just do what they did with their current ones,  transfer the Long cable ratings onto the Chest expander page.   


As another respectful warning to you,  I advised that with your Yellow near-new cable snapping and hitting the girl in the arm,  you cease using Lifeline Chest expanders altogether until they have their act sorted out re cable batch quality.
Whether for monetary gain or not,  you obviously take classes in PhysEd in a structured manner.  You will know this better than I do, that the safety and well-being of your students/trainers are your first consideration.
If that girl had lost an eye instead of merely receiving a slap on the arm, and had decided to sue,  her lawyer would have been advising her to not only sue Lifeline,  but you as well.   As the controller of the class it would be able to be proved that you knowingly and willingly exposed the girl ( under your care ) to equipment which you KNEW was erratic in quality and had many failures previously.
I'm certainly not presuming to tell you what or what not to do, I am simply conveying a warning to you as a friend,  before you become the defendant in serious financial litigation.
The other option would be for your trainers to wear safety goggles. 

      
  

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#159 [url]

Jul 31 11 12:34 PM

Re: Email Correspondence From Lifeline's Kevin Dorsey

ayeedee wrote:
Are their cables made of latex, or is dipped rubber the same thing?
I have no idea ,  sorry ayeedee.  

  

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#160 [url]

Jul 31 11 4:00 PM

Re: Email Correspondence From Lifeline's Kevin Dorsey

I believe that they use Latex Free Rubber.


The dipping refers to the process they use to make the cables. There are two main ways to extrude or dip. Dipping gives a number of layers, and (in theory!) the cables will last longer as and nicks or breaks won't immediately go through like they would if it were a solid hunk of rubber.

I'd be interested to know how Latex feels to pull vs Non-Latex, the latex may feel stretchier, but non-laytex avoids any allergy problems.

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