I recently received a prototype from a new line of machines from Randy Rindfleisch, the inventor of the Eccentric Edge leverage machines and Xntrx motorized machines. It is an isokinetic, multi-exercise machine providing both positive and negative resistance, and can be used for several exercises and a variety of protocols.
There is no weight stack or plates to lift or lower. The resistance is entirely motorized. Movement is controlled through touch sensitive pads on the ends of the handles. The user contracts against the handles or shoulder pads as they move positively and negatively, attempting to speed up the positive and slow down the negative. The users effort is then displayed on a readout in front of them, which can be used to evaluate progress between workouts.
This provides several advantages over conventional equipment.
When using free weights or conventional machines, you normally select a weight that will allow you to perform some number of repetitions or some duration of work, which is a compromise between having a heavy enough weight that the tension on the muscles is high enough but not so much that you can’t maintain that tension for adequate duration to induce a significant amount of microtrauma and metabolic byproducts of fatigue to stimulate growth. When you do this the only time your muscles are contracting as hard as possible is the point when their momentary strength has been reduced to the level of the selected resistance. From the start of the exercise up until that point, they are not working as hard as possible.
Since the muscles are capable of resisting far more force during the negative than they can contract against during the positive, they are worked even less intensely during the negative when using conventional equipment. For example, if you can lift 100 pounds at in an exercise you can lower about 140 pounds under control at about a 4/4 cadence (the ratio of positive to negative strength varies with concentric contraction speed). If you select 80 pounds of resistance for an exercise, you are lifting 20% less weight and lowering over 40% less weight than you are capable of at the start of an exercise. Since the negative portion of an exercise is the most important for stimulating growth, this is a serious shortcoming.
There is a way around these problems using conventional equipment called “hyper” repetitions, a protocol used in the early days of Nautilus which required several helpers to assist the trainee in lifting a weight far heavier than they would use for a normal set, then applying additional resistance during the negative, resulting in maximal difficulty in both the positive and negative portion of the exercise. However, hyper reps are somewhat impractical to perform, very tiring for the helpers, and can be dangerous if done improperly, and make it difficult to objectively quantify performance.
The machine makes it possible to perform hyper repetitions with no assistance and in complete safety since there is no weight to be dropped. The movement arms will instantly come to a smooth stop (stop and turnaround acceleration is adjustable) and remain still at any position if the user takes their thumb off the sensor. On the prototype effort is measured as draw on the motor and displayed in front of the user, and the production model will have a screen in front of the user displaying the force applied at the movement arm, making it possible to objectively quantify performance and evaluate progress between workouts.
It also makes it more practical to perform other advanced high intensity training techniques like negative-only and Max Contraction. From a personal trainer’s standpoint, this saves a tremendous amount of physical effort. If you’re training a dozen or more people per day several days per week and using forced reps, negatives, forced negatives, static holds, etc., it can get pretty tiring. Additionally, this makes it possible for a small female trainer to have clients perform hyper or negative only reps with a level of resistance she could never lift for them with conventional machines or free weights. It also makes it possible to perform exercises like squats and deadlifts negative only, which are otherwise highly impractical.
Since the resistance equals the effort throughout the exercise, it automatically accommodates the user’s strength curve over the full range of every exercise. Since strength curves vary between individuals, especially in linear movements where the start and end points vary with limb length, and may even vary somewhat from repetition to repetition due to different rates of fatigue in muscles of different fiber type composition whose relative contribution to a movement varies somewhat from position to position, this is something that is impossible to accomplish with free weights or conventional weight-based machines. Even other motorized machines which alter the resistance between repetitions or between the positive and negative through manipulation of weight selection or levers can’t do this.
Sunday night I performed a brief workout on the machine, consisting of squats, pulldowns, presses and calf raises. The speed of the machine is currently set to 10/10, although it can be adjusted to be faster or slower. I performed three “hyper” repetitions of each, with a maximal effort during both the positive and negative, and took about about two minutes of rest in between. The total workout time was around 12 minutes. I have performed negative only and hyper reps before, but it doesn’t even begin to compare to this. The negatives were particularly brutal. The machine is surprisingly smooth – I think the turnarounds would even impress Ken Hutchins – and the controls are incredibly responsive. Switching positions between exercises is easy and quick – the seat for dips, pulldowns, presses and shrugs can be removed for the leg exercises, although when set to the lowest position it is out of the way for deadlifts and calf raises. The seat height is adjustable, and I have trained a friend who is 6’2″ and 200 pounds and my wife who is 5’2″ and 95 pounds with no problems.
Thursday night I performed a negative-only workout, consisting of squat, row, chest press and stiff-legged deadlift, doing three 10 second negatives of each with approximately 10 seconds between reps. Although the negatives were still brutal, the workout wasn’t quite as exhausting without the positives even though I only rested about a minute between exercises. The total workout time was under 10 minutes. Normally I would perform additional work for the forearms and additional direct arm work occasionally, however I want to evaluate the results from using the machine only, so I will not be using any other equipment for the next couple weeks.
The machine was designed specifically for squats, calf raises, deadlifts, dips, pulldowns, presses and shrugs, but also works well as a chest press or compound row if you lay on the seat and use the seat belt to hold yourself down for the row, and I suspect bent over rowing and stiff legged deadlifts may also work well, although you wouldn’t be in a position to view the screen. Randy has designed another machine for chest press and seated row, though, so I don’t know if this one will be modified to be better suited to the performance of those exercises. That other machine was designed for leg press, calf raise, chest press, seated row, and leg curl, and also provides an abdominal exercise.
Based on what I’ve been able to do with it so far, I’m planning on rotating between the following workouts on it, and will film some of these to post here:
Routine A:
- Squat
- Pulldown
- Shoulder Press
- Stiff-Legged Deadlift
Routine B:
- Deadlift
- Dip OR Chest Press
- Row
- Calf Raise
I am also going to be training a few friends and family members over the next couple months, and will report on their progress with the machine as well.
Update September 2018: I would caution people against using hyper reps on these/continuous max effort. I will eventually write an article with updated protocol recommendations for motorized machines.
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I just responded to a post on Ellington Darden’s HIT discussion forum about the X-Force machines, which use a motor to tilt a weight stack to alter the resistance between the positive and negative, and the following additional benefits of Randy’s Hybrid machines over machines with weight stacks (motorized or not) occurred to me:
“Also, many weight stack machines lack enough resistance for stronger users for even regular reps, much less negative only. I have had many clients max out Nautilus and MedX machines – how much more resistance would a machine require to make the negatives really challenging?
Doesn’t matter how strong a person is, the motor and the way this machine is geared make the resistance impossible to overcome. No matter how strong you are, the resistance is always enough.
Of course, you can always have people stand on a weight stack, but I don’t see how you could get people to stand on the X-Force’s weight stack with it moving and with the shielding over it.
The motorized resistance in Randy’s machine is much safer as well. It is impossible to lose control of or drop the weight, and if something happens the user can unload instantly at any point in the ROM, without needing to set down or transfer a heavy weight to a trainer or training partner.”
How much would these machines cost, Drew?
I do not know what the production models will cost, as they are still in the prototype stage. Because of the materials they will probably cost more than a conventional selectorized machine, however since they perform several exercises each they are more economical in terms of cost (both purchase and shipping) and space than the number of conventional selectorized machines required to provide the same number of exercises. The prototype I am testing can be used for squats, deadlifts, stiff-legged deadlifts, calf raises, dips, pulldowns, presses, and shrugs, and although it is not designed for it I have been able to use it for chest presses, rows and abs/trunk flexion as well. There is a prototype of another machine that can be used for leg press, leg curl, calf raise, chest press, row, and abs which is also going to have other exercises added to it. Randy has already designed several multi-exercise machines providing single joint movements which were produced in his Xntrx line, and I hope some of those are adapted for the new line as well.
The next time you plan to be in Florida let me know if you want to come by and work out on it.
Drew,
Do you find the linear path of the machine to be a problem? Do you feel ‘locked’ into certain positions with exercises like Squats and Stiff-Legged Deadlifts?
Thanks
A linear path isn’t a problem in these exercises at all. When you perform these exercises with barbells, the heavier the weight becomes the straighter the path must become to keep the bar over the feet and maintain balance. During a stiff legged deadlift, for example, if you are using a heavy enough bar, you must start with it positioned directly above your feet. Your shoulders don’t go very far forward of it, instead, the hips move backwards. Otherwise you would tip forwards as you perform the exercise. If you watch someone perform any of these exercises with an adequately heavy weight you’ll notice the path is pretty straight.
Consider what happens as a person uses progressively heavier weights in a barbell curl. When someone curls a light weight, if they are attempting to use strict form there is very little sway of the body. However, the heavier the weight, the more of a backward lean is required to maintain balance as the forearms approach horizontal. As the mass of the barbell moves forward, the mass of the body must be moved back to maintain the center of gravity of their combined mass over the feet. The heavier the weight used, the greater the percentage of the combined mass it becomes, the closer the center of gravity of the combined mass gets to the barbell, the further back the body must lean to maintain balance, the more vertical the barbell’s path becomes. Since the barbell curl is a rotary movement and the weight used doesn’t approach multiples of bodyweight it will never be completely vertical, but it gradually gets closer to it as the weight gets heavier. Squats and deadlifts are relatively vertical movements to begin with, and even the stiff-legged deadlift is pretty vertical to begin with, so heavier weights in these result in something pretty close to a straight line.
If you’re not sure about the stiff-legged deadlift, try the following. Stand with your back to a wall so your hips are in contact with it and your feet are directly below you and attempt to bend forward and down while maintaining your balance. You can’t do it, because to maintain balance your hips need to be able to move back to counterbalance your upper body mass as you lean forward. Watch someone else perform the exercise from the side with a heavy weight and you’ll see the barbell will travel up and down in a relatively straight line.
AWESOME!!! Just viewed the article on Dr. Darden and saw Ur response. Its a major breakthrough. To perform negatives as heavy as one could do in total safety is what we need. How do U select resistance in the machine? Just curious. I feel that this might be the one machine, that I’ll have to invest in when I open up my facility in India. Looking forward to hearing about Ur evaluation of the machine and the progress on it.
Karthik,
There is no resistance – the handles or pads move at the selected speed positively and negatively no matter how hard your muscles contract against them. The exercise will always be as intense as necessary for the user. Progress is measured by force output, which is displayed on a screen in front of the user.
Hey Drew,
I have one question too: Is the ROM (start/endpoint of the exercise) freely programmable or do you have to reverse the movement manually via that button on the handle every time yourself? If so, how do you make sure progress happened with (possibly) varying ROM from rep to rep or workout to workout?
Regards,
Franco
The user or trainer are always in control of the movement, which is safer. The display will show your position during an exercise (angle on rotary movements, distance on linear movements) so you will know if you are performing the exercise over the same ROM.
@Franco
Forgot one more: Are you stuck with the parallel grip or are the handles pivoting so you could use underhand/overhand grip too?
The handles on the prototype are in a fixed position. I do not know if the production models will have multiple handle positions, but I would not be surprised if Randy incorporated these. His machines tend to be very adjustable.
Thanks so far, Drew.
I believe Randy should include a programming (and saving) of exercise related ROMs in the production models. It will free the mind to put forth even more effort, instead of watching/guessing when to “push the button”. The safety is no problem as the button could stay in place for that very reason.
Franco
This will probably be included, however I can not say for certain what the production models will feature.
You may give him the hint? 🙂
Is there any date for commercial production to start?
Thanks again,
Franco
I do not know, but there are already a lot of people interested so I don’t think it will be long. As good as the prototype is, I’m very psyched to try out a production model. Additionally, the company is located in Wisconsin which is where I’m from, so it would be a great excuse to fly home for a visit.
Drew:
About 10 years ago I tried a unique machine that used a motor to provide maximal positive/negative resistance along with providing graphical feedback. I cannot recall the machine’s name but it was something like the Equalizer or the Terminator, something that sounded imposing. It allowed for various compound movements – various presses and pulls. This was at Joel Waldman’s gym in Bellmar, NJ…literally just off the beach. I was not a member, was merely passing through, found both Joel and his facility to be uncommon and worthwhile. Lots of MedX, Lamb, Nautilus including some stuff I’d not seen elsewhere.
Since you’ve encountered most everything WRT strength training, perhaps you’re familiar with what I vaguely described. Joel put me through one all-out set of pulldowns on this monster. I believe rep speed could be pre-set and was then impossible to deviate from. I do recall performing not very many reps but each was excruciating in duration and effect. I was quite surprised that almost every muscle in my upper body became horribly sore for days afterward – including some most would not think would be engaged during pulldowns. With the graphical feedback, Joel could tell if a victim…er…trainee was dogging it to even a tiny degree.
I loved it, always intended to try a squat on that device but never made it back to Bellmar. If Randy’s machines are similar in effect…wow. Was the squat on this machine more intense than just about anything you’ve done before? How about post-workout fatigue? The day after my experience, I was wiped from that one crazy set.
Thanks. Keep up the good work.
Hey Chris,
I remember hearing about the machine you mentioned, but never saw or tried one. I tried the Lamb plate-loaded rowing machine when Joel brought it to a SuperSlow Exercise Guild conventions years ago and was impressed with it.
While every exercise on Randy’s Hybrid machine is brutal, the squat is particularly devastating. Negative-only reps leave your legs deeply fatigued and sore for days afterwards, and hyper reps do the same while also completely exhausting you. In about two months I will be retesting my strength on barbell squats, shrug bar deadlifts, presses, chins and dips, and it will be interesting to see how it goes. Back in the ’70’s the Deland High School powerlifting team went undefeated several years in a row while using negative-only training under coach Bill Bradford, so I think the results should be good.
Hey Drew,
The positives on an Iso Kinetic machine are fine. We exert more force than the previous attempt and gauge progress. How do the negatives work? Does the machine provide a negative force that the user will be trying to resist? If so in what accordance is this negative force generated? Does the motor generate the negative force based on the positive phase of the exercise. Or can the required degree of force be set using the display meter? Would be great if we could see a video of U performing squats or pulldowns on the machine
Karthik
Karthik,
Randy’s machines are very different than the old isokinetic machines which provided only positive resistance. The speed is adjusted for the range of motion and desired protocol and the user contracts against the movement arm as it moves positively and negatively. The resistance during positive, static, and negative movement is proportional to the user’s effort – no matter how hard you contract against the pads or handles, you can not speed up or slow down the movement arm. A display in front of the user shows them how much force they are producing for motivation and tracking and evaluating progress.