Gravity Based Exercise Equipment vs. Motorized Exercise Machines

This is a video blog I made yesterday on my Arx Fit Omni. In it I discuss the superiority of motorized exercise machines over gravity based equipment, including

  • dumbbells
  • barbells
  • kettle-bells
  • body weight exercises
  • selectorized equipment

My argument boils down to one fundamental point, with two distinct derivative points.

Primary point

An intelligent alien being, with an intent to build an exercise machine for universal human use, with no external influences in the realm of exercise equipment, would not build an exercise machine that requires the user (~7 billion people) to adapt to the machine. That being would have to build an exercise machine that adapted instead, to the user.

Which is the exact opposite of most exercise equipment seen today.

Derivative point 1:

Gravity based equipment is incapable of perfectly adapting to bio-mechanical variables that change from person to person, however large or small.

Motorized exercise equipment, does.

Derivative point 2:

Gravity based equipment is almost universally incapable of adapting to a user’s increasing fatigue during live, intense use. Motorized exercise machines not only adapt to the user’s demands, they do so with 100% precision.

What about negatives?

Good question. This is something I did not discuss in the video.

The short version: with no external influences, why would an alien being build an exercise machine for universal human use, that does not track for a large increase in strength on the negative portion of every repetition?

Given the choice, it seems a little silly that you wouldn’t design a machine to provide the musculature with the resistance you ask of it, which is much higher on the negative of every rep.

So bottom line: same principles apply.

When does the set end?

From a Youtube viewer:

But if the machine is constantly adjusting the resistance to match your strength as you get tired, when does your set end ? You would never hit failure if the weight is continually being reduce. I don’t know cause I am new to this motorized stuff

My answer:

Good point. I think the answer lies in the fact that you now have more control, and responsibility over, when the set ends.

In a 100% volitional activity like exercise — from conception to being sprawled out on the floor — more control and responsibility being in the hands of the individual user and/or trainer, is always a good thing, by my judgement.


Links from the video.

About Anthony Dream Johnson

CEO, founder, and architect of The 21 Convention, Anthony Dream Johnson is the leading force behind the world's first and only "panorama event for life on earth". He has been featured on WGN Chicago, and in the NY Times #1 best seller The Four Hour Work Week.    His stated purpose for the work he does is "the actualization of the ideal man", a purpose that has led him to found and host The 21 Convention across 3 continents and for 6 years in a row. Anthony blogs vigorously at and

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30 Responses to Gravity Based Exercise Equipment vs. Motorized Exercise Machines

  1. Joshua Trentine May 30, 2012 at 5:37 pm #

    see: DUMPERS IV on the RenEx site (will release in the next week)

    Joshua Trentine

    ps you might want to ask your friend Drew Baye about this gravity based concept I think he can help you understand.

    • Anthony Dream Johnson May 30, 2012 at 5:41 pm #

      Hey Josh

      Will do, been waiting patiently for part 4 to release actually.

      Speaking of which, I think I’m making a pretty substantial point here in disfavor of all selectorized, gravity based machines, as compared to a properly designed motorized machine.

      I suspect the RenEx team has never been confronted with these arguments before. If that is the case, and if there is interest and motivation to respond to them, I’d love to see the response, and I’m sure many of my readers would as well.

      — Anthony

  2. Joshua Trentine May 30, 2012 at 6:07 pm #

    Hey Anthony,

    Way ahead of you, the Dumpers series is a detailed report.

    I have no problem with you saying ARX is best, but you really should experience and comprehend what you call inferior. The people who seem to be interested in this technology like the idea of training hard and enjoy going through the motions, but comparatively have no real desire to contract the muscle for the purpose of stimulating the adaptive response. Getting drug through an exercise is less productive than a tug of war. Having machines that act upon you is the furthest thing from customization.

    The Dumpers series is my final word on the subject.

    Joshua Trentine

    • Anthony Dream Johnson May 31, 2012 at 9:44 am #

      Hey Josh

      As I hinted at in the video, I have experienced a (limited) range of (prototype) RenEx equipment. Even the prototypes (at Ken’s studio in Altamonte) were without a doubt the best selectorized machines I have ever used. There was a lot more to appreciate with the studio as well, so overall, a fantastic experience.

      Never the less nothing I saw, nothing I have read, and nothing I have even remotely heard of, suggests to me that *any* selectorized machine (regardless of quality, piss poor or absolutely out of this world) is better than a properly designed motorized machine (with would *not* include x-force).

      I am arguing from the point of an accepted basic premise, the most fundamental point we can discuss, and I am arguing that the basic premise that an Arx Fit Omni operates on, is the only correct one in existence.

      — Anthony

  3. Bill DeSimone May 30, 2012 at 8:00 pm #

    Hello Anthony. OK, this is interesting, I’ll have to see if there’s one in NJ/NY to try.
    My preference at the moment is conventional weights and stacks. Well, and the Bodyblade, but never mind. But the added negative certainly makes the workout more efficient.
    I had tried the old Lifecycle computerized equipment from 20(?) years ago. These pieces had you do one rep to set the range. the negative was heavier than the positive, and across a programmed 12 reps set, the resistance did a pyramid: 80%, 90%, then 100% for 8 reps, then back down for the last two. I could never finish a full set of 12, I burned out in the middle of the set. Lucky for me they were so expensive I never saw them outside of trade shows, or I might have quit training if i had to go through that agony.
    Currently, as far as adding to the negative goes, I don’t regard it as mandatory (because obviously you can progress other ways), but it certainly could be useful.

    • Anthony Dream Johnson May 31, 2012 at 9:49 am #

      The BodyBlade is definitely a fun tool =). Not sure if there is an Omni in NY/NJ, you could ask by email though.

      I believe John Little is testing one up in Canada too if you felt like making a trip out of it.

      Re negatives, I’m not arguing that they are mandatory either. As usual I’m arguing philosophy =). In this case, the body is asking for more resistance on each negative repetition … so why not provide that resistance, as asked, if it’s available?

      • Joe A May 31, 2012 at 10:58 am #

        The body’s ability to absorb, disperse and withstand greater amounts of force on the ‘negative’ is a far cry from the body “asking for more resistance on each negative repetition”.

        I find it odd that you speak of a concern for your joints/structures (a la CE, biomechanics, etc) out one side of your mouth and then turn around and promote loading yourself in this manner outside of the other. This is not a sustainable model for muscular loading during exercise, IMO and IME. That said, there are limited applications in which it could be really useful. Outside of those applications, there are safer ways to load the body that are *at least* equally effective, if not more.

        • Anthony Dream Johnson May 31, 2012 at 11:55 am #

          Hey Joe

          I fully agree that the bodies capacity to safely withstand a greater amount of force is a *different and separate* concept from it’s capacity to load a greater amount of resistance in the negative portion of any particular physical movement. It is actually a comment left by you on BBS that alerted me to this distinction, well in advance of actually getting my Omni machine. I.e. why would you want to lower something if you can’t lift it.

          This begs the question though : is the human body not capable of withstanding the forces generated by the resistance *it is capable of loading in eccentric contraction* in a safe, slow, controlled manner? In fact, the resistance the muscles in a sense “request” when under 100% exertion?

          I.e. if you can safely (acute) lower it, what law says the body is incapable of doing that, without long term negative consequences?

          I am under the impression that the human body has few weak links, and is overall, a fine tuned, well functioning machine. As such, it seems unlikely to me that the body would be capable of adequately resisting willingly and slowly applied, controlled forces that it was not also capable of healthfully withstanding.

          Finally, perhaps this is not well known information, so I should make it known in this discussion.

          The Arx Fit Omni is capable of providing positive only resistance, negative only resistance, or obviously, both. It also tracks your force output by the second, and my model happens to be especially accurate. This provides instantaneous feedback to a trainer, trainee, or both, during every exercise, and allows a capable trainee to adjust his efforts accordingly.

          Easier said than done under duress, but by no means impossible, or perhaps, no more difficult than changing your repetition speed (live) on a selectorized machine, on your own account, or by the advisement of your trainer.

          • Joe A May 31, 2012 at 12:36 pm #


            Just to be clear, my post was in response to your statement to Bill re: negatives, not your post about the Omni. I’ll refrain from addressing specifically a machine I have not actually used…however, the feedback is the coolest thing about machine, at first glance.

            The amazing thing about the human body is its ability to withstand the multifarious stresses it is faced with AND respond and adapt to them. Specifically, if you impose great loads on structures, your body will *bend* to accommodate and protect itself (realize the *bending* is not just acute but can become a permanent adaptation). However, it’s capacity to *bend* is not something I want to regularly test.

            As far as force output, are you saying that muscle is more capable to *produce* force during eccentric phase? Or, are you saying that via bracing, successive recruitment of surrounding structures, etc. during eccentric allows for the lowering of greater loads than one can lift?

            I don’t think hyperloading the negative is a good thing. IF your equipment has friction issues and you choose to address them by loading up that phase…that really isn’t hyperloading…you are just trying to give back what friction is taking away (friction takes away 20-40% and you add 20-40% and you have a net of your positive volitional capacity). IF, on the other hand, you are truly hyperloading, then “No” I don’t believe you can sustain that, long-term without consequence.

            And, BTW, apply your same logic as when speaking of proper biomechanics to safely lowering a heavy weight…just because you can get away with it today, doesn’t mean there wasn’t a consequence and doesn’t suggest you’ll fare as well tomorrow.

        • Anthony Dream Johnson May 31, 2012 at 12:02 pm #

          Hey Joe

          Re concern for my joints and structure, I do walk my talk, and only become more paranoid by the day about the long term effects of *any* resistance training on my body, the more I read Bill DeSimone’s work =).

          Excessive caution is better than less is the conclusion I have come to.

          Regarding the ARX specifically, I am really cautious with everything I do on it, and anyone I train on it, to the point of absurdity for anyone unfamiliar with Bill’s work. Not because of anything specific he’s ever wrote … but because of the attitude/approach/focus to/on safety in the first place.

          I’ll be making workout videos soon enough. I think it will shed some light on what I mean by safety.

  4. Donnie Hunt May 30, 2012 at 8:52 pm #

    In the words of Shang Tsung, “IT HAAASSS BEGUUUN!!”

  5. Joshua Trentine May 31, 2012 at 1:05 pm #


    You are right Ken does have some of the best machine that exisit, but you have not been on the RenEx machines. I don’t even have them down in Florida.


    • Anthony Dream Johnson May 31, 2012 at 2:03 pm #

      Hey Josh

      I said the best *selectorized* machines. Bit of a difference from the best machines period =), hence our disagreement.

      Re the machines themselves, I was under the impression that the machines I tried were in fact prototype or early versions of RenEx’s new, and final equipment.

      To be clear, is this not true, and were the machines I used at Ken’s studio with Drew in fact something else? (Old SS equipment?)

  6. Joshua Trentine May 31, 2012 at 1:07 pm #

    Something Drew posted:

    With regards to adapting to the user, one of the most important things is proper biomechanics. All of the motorized machines out there get this wrong, and ARX in particular make huge compromises in this area to cram multiple exercises into a single unit. You can build a machine that is very well suited to a specific exercise, or one that provides many exercises but does none of them particularly well.

    Resistance curves are an important aspect of equipment design, but only one of many. While motorized resistance can match anyone’s strength curve (assuming proper use) this doesn’t make up for the various disadvantages (discussed in the RenEx “dumpers” articles) and maximum resistance from the very start is undesirable, for the reasons explained by Arthur Jones in Nautilus Bulletin 1 in “The Harder It Seems – The Easier It Is”.

    I experimented with heavy negatives, rest pause, and other protocols for a while, and had decent results with them, but no different than with other, “normal” HIT protocols. The only thing they produced which the other HIT protocols did not were joint soreness (rest pause) and a lot more general soreness (negatives).

    I took down all of my old articles on the motorized machines because although I made very similar arguments they turned out to be wrong, mainly because there were things I had not considered or been aware of wrt various safety and control issues.


    • Anthony Dream Johnson May 31, 2012 at 2:07 pm #

      Josh, I’m not positive that Drew is talking about the same machine. I suspect he may be referring to the industrial versions of the ARX machines, which are very different from the Omni.

      As I also responded to Drew, maximum resistance from the very start of an exercise on an ARX Fit Omni is thus far impossible for me, and everyone else I have ever seen use an Omni.

      It’s just not possible.

      100% effort on the first rep =/= 100% physical and mental exertion

      My own workouts tend to peak around the third rep, and this is not even counting the 2 warm up reps I do at minimal effort.

  7. Shickalee May 31, 2012 at 2:22 pm #

    Anthony, will you be posting a Big 5 workout video utilizing the Omni in the near future? That is where my interest lies in regards to the Omni.

    • Anthony Dream Johnson May 31, 2012 at 2:35 pm #

      Hell ya I will! A few dozen to be sure.

      • Shickalee May 31, 2012 at 9:49 pm #

        Just to be on the same page for BBS with the Omni. Would the leg press be replaced by the squat, and the bent over row for the seated row.

        • Anthony Dream Johnson June 1, 2012 at 11:26 am #

          There are different variations of the row you can do on the Omni, so you can take your pick.

          The leg press would be replaced by the belt squat most likely. You could also dead lift for a similar effect.

  8. Joshua Trentine May 31, 2012 at 3:14 pm #

    They were SuperSlow machines

  9. Alex June 3, 2012 at 9:02 pm #

    The point of weightlifting, in its most basic sense, is to get the BODY to ADAPT to external stressors. Making a machine that adapts is neat, but if the machine is doing the adapting, then the body is definitely not (AKA no gains in strength.) The weak parts of each motion stay weak, and the strong parts stay strong. What’s the point of that? What’s the point of strength training if you leave part of the motion weak? It sure as hell doesn’t matter if you can get 300lbs off your chest if you can’t lock it out. Why pander to the weaknesses of your body instead of addressing them?

    An analogy: Replace adaptation to weight training with adaptation to distance running. You’re not gonna say “man, i can run the first 100 meters really fast, but then i get tired so i’m just gonna walk the next mile.” That would be dumb, and i’m sure you understand why. What is the difference between changing the weight stimulus based on where you’re weaker and changing the running speed stimulus based on where you’re tired?

    In regards to bio-mechanical variables unique to each person: first, give some examples of those, please. You make these claims, and not only provide no support, but don’t even give examples of what the evidence would support if there were any. I can’t just say “there are a lot of variables in this issue” and expect that to carry any meaning. Not only am I not giving evidence that the variables are important to the issue, I DON’T LIST ANY variables. Do you see the issue??

    If by “bio-mechanical variables” you mean things like skeletal structure, muscle structure, etc.

    An example of how gravity based training does in fact cater to all kinds of factors:
    In the deadlift, both femur and arm length are determining factors in starting back angle and hip height. If you’ve got short arms and short femurs, you can drop your hips very low because the bar won’t have to travel forward to clear your knees. This means your starting back angle can be more vertical. If you’ve got long femurs, your hips will start higher, so that your knees are less extended => the bar won’t have to move forward to clear them.

    Not only are “bio-mechanical variables” addressed by form and starting position, but they are covered by starting weight, too. Let’s say you’re benching. If you’ve got weak triceps and a beast chest (we’ll ignore lats/front delts, etc) then you’ll have a hard time locking out weights you can easily get off your chest. There are many ways to move past this:
    A)Use a lighter weight that your triceps can handle to illicit an adaptation; once they are caught up sufficiently, the chest will become more involved until a good balance is reached and they effectively both become the weak point.
    B) Use additional assistance exercises to shore up the weak spots. Close grip bench, for triceps, in this example.
    C) Use dynamic resistance methods (chains, bands) to overload whatever the fuck you want. You can make any part of the movement harder with smart programming.

    These are just the simple ways to address a couple things that might be called “bio-mechanical variables”.

  10. Craig June 3, 2012 at 9:17 pm #

    So if I understand what I am seeing, the machine moves the resistance element at a slow, constant speed, and you push against it to the extent you can, with the amount of force being determined by how hard you can bring yourself to push (concentric) or resist (eccentric)?

    If so, then this could be described as an isokinetic exercise with both concentric and eccentric resistance. However, the speed of movement is fairly slow, and (I assume) not influenced by the force being applied by the user. So as far as what the user experiences, it probably seems more like an isometric contraction, albeit against a slowly moving element rather than a fixed object? I’m tempted then to call it a quasi-isometric exercise with concentric and eccentric stretching over a full range of motion…..

    If it really is more like an isometric contraction, then the phrase “dumpers” seems ill applied. That phrase makes a lot more sense with something like X-Force, where you have an externally imposed overload that the user must resist lest they lose control of the movement. In contrast, it seems that on the ARX, if you relax your muscles, the applied force immediately drops to zero.

    With regard to the safety issues for this machinie, how does the notion of negative overload even come into this? I’ll grant that you can probably resist the bar with more force than you can exert on a concentric movement. But would the force of resistance ever exceed that which you could generate with an isometric contraction against a fixed object? If you think that the negative portion of the ARX exercise is too dangerous, then promotion of Timed Static Contractions would seem equally reckless.

  11. Joshua Trentine June 4, 2012 at 11:44 am #


    I have no idea how staged, volitional effort can be compared to a machine acting upon you.

    Like I said we cover this in the Dumpers series, Part IV includes ARX.

    We are strongly opposed to Dumpers and Isokinetics… and no ARX is not an isometric modality.

    If our position isn’t clear in these articles there is nothing more I can include.


    • Craig June 4, 2012 at 7:10 pm #

      “I have no idea how staged, volitional effort can be compared to a machine acting upon you.”

      Perhaps you are trapped in a particular paradigm, and need to be a little more flexible in your thinking?

      I’d review Dumpers IV, except as I post this, it doesn’t appear to have been published yet.

      I understand that you are strongly opposed to these machines. Strong opinions are widely available on the internet. For any subject. For any point of view. So what?

      • Anthony Dream Johnson June 4, 2012 at 7:49 pm #

        Craig, I agree, and strongly suspect that the RenEx founders are trapped in the paradigm of selectorized, gravity based machines.

        I in no way doubt their rigorous intellectual honesty and integrity … but I do suspect psychological barriers are in place after dealing with selectorized/gravity based equipment the entire duration of their adult lives. To think coherently outside of that realm is a monumental task in itself after doing so for so long …

  12. Joshua Trentine June 5, 2012 at 12:52 am #

    You under estimate my range and experience, bottom line if I thought it would stimulate adaptation I’d build it and do it better….motors aren’t really too tricky and they are cheaper than weight stacks. If I tried to train on that thing I’d do nothing but loose muscle. I’d rather own a barbell.


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