For years, training technology has gone beyond just free weights and selectorized equipment. Decades ago, technologies like isokinetic machines hit the market and began to be embraced. There was, however, a period in recent memory in which many strength & conditioning coaches seemed almost allergic to the idea of embracing much of anything outside of barbells, dumbbells, kettlebells and the like. That’s changed.
In recent years, the performance and fitness space has become far more open to technology having a role: whether it’s deepening assessments in order to better inform training decisions or the resistance training technologies we’ll be covering in this guide, innovation isn’t just for automotive, AI, and other industries. It’s impacting the physical training space as well.
The category of resistance training technology has become this whole nebulous unto itself where most non-flywheel types of strength tech tend to get bucketed. This means that the types of machines listed here and the corresponding adaptations they can create may vary considerably from item to item.
In rehabilitation, one form of assessment is diagnosis by elimination (such as with certain quadriceps tendinopathies and thoracic outlet syndrome diagnoses), in which if they can’t quite figure out what something is or where it fits categorically, they may elect to bracket it under another term. You can think of this guide as something like that—a list of resistance training technologies that can be quite helpful, but the tools may ultimately have minimal overlap in terms of the adaptation they’re providing.
The drivers behind the development of motorized equipment are:
- Make training more efficient.
- Offer a unique stimulus mostly not captured by other options.
- Offer a means of safety and control of progression.
The typical ability to control load and speed during both the concentric and eccentric phase of any movement allows for the application of specific training modalities—research has shown promising results for motorized equipment when compared with traditional methods.
A recent study showed that a combination of eccentric overload, isokinetic strength training, and ballistic training yielded better results than both Olympic weightlifting and traditional weight training. While we’re not advocating abandoning all free weight work, it’s clear by now it doesn’t check all the adaptation boxes. Some of this may stem from the ability of certain machines to load target tissues and/or enable loaded power and speed motions without as much room for negative adaptations (unwanted structural repositioning and neurological inefficiencies) *some* traditional strength training could provide.
Controlling load & speed during both the concentric & eccentric phase of a movement allows for specific training modalities—research has shown promising results for motorized equipment when compared to traditional methods. Share on XOver the last 10 years, resistance training beyond barbells and dumbbells has merited a comprehensive guide to those options in training and rehabilitation. Terms like “isokinetic,” “isotonic,” and “isoinertial,” now much more mainstream, are sometimes explained correctly and sometimes misunderstood. For the sake of simplicity, this review will cover any resistance machine that requires electricity and a computer or similar.
The market is in its early stage in some areas while being established in others and therefore cloudy with both biological science and engineering, so this guide covers what steps to take (and why) in order to make a purchase. At this moment, the better part of a dozen or more companies are viable options, since it takes more than just building a machine to be a solvent company. If rehabilitation, human performance, research, and health optimization interest you, you will benefit from this outline and these recommendations.
What Do We Mean by “Resistance Training Technology?”
Let’s start by defining what we mean by “resistance training technology” and adding context, so what types of tech are included vs. not included is made clear.
The cornerstone of an electronic resistance machine is that the resistance comes from a motorized option, usually controlled by a combination of the settings, the user, and sometimes a computer. Typical barbells, flywheels, and cable machines don’t require electric power to change their resistance, so any equipment that can run without power but uses technology is considered a separate tool. Also, mere quantification metrics aren’t being counted in this guide.
Plenty of traditional squat racks and platforms are made “smart” because they use sensors and displays, but the technology doesn’t affect the resistance type. If the load is traditional and simply being quantified for the user, the device is simply not motorized resistance—it’s just a traditional piece of equipment with technology features.
Most—if not all—equipment listed here not only produces novel resistance, but also measures the output of the resistance from the user. Some systems display the output in real time while some record and display it through a computer or tablet wirelessly. Many also now offer unique apps and cloud-based technology so users can track their progress over time to see where they’re at.
An easy way to summarize the function of motorized resistance machines is that they use technology to create, measure, and report human output in training.
While some machines simply create resistance and don’t report much data on how that load interacts with a human, the benefit of specific resistance modes is the central driver to adopting such equipment. In other words, the equipment is providing some type of unique adaptation not generally found in free weight or selectorized, isotonic resistance options.
A resistance that can’t be found in traditional gravity- and pulley-based equipment is the primary value of the machine, and data from it is generally a distant second. Quantification of the load tends to be built in, but isn’t always something coaches need to track aside from perhaps showing clients their progressions in order to motivate them.
Although being able to identify progressions within a given load type is important for progressive overload, these numbers aren’t necessarily standardized (and, neither are free weights). There’s no guarantee if you hit squat number ___, your vert will increase ____ inches. At any rate, what’s important to pay attention to is that the things outside of a given machine are moving in the right direction accordingly—speed, velocity, jump heights, rehab times, and other types of output-based metrics should progress alongside chosen resistance types. For example, the Proteus has a measuring device to add more precision, but we could look for a cause and effect with indirect testing outside of its own intrinsic data.
The things outside of a given machine should be moving in the right direction—speed, velocity, jump heights, rehab times, and other types of output-based metrics should progress alongside chosen resistance types. Share on XResistance Types
Isokinetic Resistances (Isovelocity, Accelerating Isokinetic, Adaptive Isokinetic)
Isokinetic resistance is a classic example of “what is old is new again,” with a resurgence in popularity in recent years. One of the sections from the last guide that got a bigger makeover is isokinetic. Both our understanding—and the collective equipment offerings—have evolved since the last time of this writing.

Classical research and rehab isokinetic machines provide resistance where the device manipulates force and speed at a fixed velocity with matching resistance concentrically and eccentrically. Historically, research, rehab, and sports science has used basic isolated open-chain assessments like hamstring or quadriceps testing to observe differentials in strength. This type of machine can aid in bringing up weak points in isolation and can be useful to tease out potential differentials that could show up on foot in more dynamic actions.
It’s also important to note that the term isokinetic has a few different permutations other than the original isovelocity version. Some machines also feature adaptable resistance that matches the user’s own capabilities. This option spotlights safety, as someone is only ever doing a relative max intent (if cued that way). The ability to perform more reps under fatigue with a load that adjusts intra-set is another cool feature. These types of isokinetic machines also mean that regardless of a user’s capabilities, the machine can always adapt to progress right alongside them. Of course, there are rehab implications here with load options that can match whatever phase one is at in the reconditioning process.
Although not a new concept, inventor Mike Mattox’s original accelerating isokinetic machine (known as The Jumper at one time) has gained more popularity online. This type of resistance offers a concentric-only stimulus that starts heaviest and accelerates through the motion along with the user. The eccentric action is unweighted, allowing athletes to intentionally yield into their eccentric actions. This makes this an intriguing option for loading ultra youth athletes without compressing them as much—as a primer before plyometric activity, for example—as well as being a phenomenal rehab tool. The stimulus to this type of resistance comes in the form of a fan blade, does not offer metric tracking, and can be thought of as something of a moving overcoming isometric that strengthens joints “maximally” through a full range of motion.
Isokinetic training is still relevant, effective, and an increasingly interesting option as there are various types of load and more equipment focused on multi-planar motion & multi-joint actions.
Eccentric Overload
Flywheels can provide a rapid eccentric force, but true overload is when the net demand is higher than the concentric component. Dialing up eccentric forces with machines is possible with an array of equipment lines that provide controlled overloads at specific ranges of motion and speeds. Obviously, safety is a factor and machines are designed to reduce risk and improve outcomes.
Dialing up eccentric forces with machines is possible with an array of equipment lines that provide controlled overloads at specific ranges of motion and speeds, says @RewireHP. Share on XSome coaches use more controlled, “maximal strength” eccentric overload in order to prep target tissues and load joint actions that could improve the athlete’s ability to tolerate forces encountered in real time at higher velocities. Dr. Pat Davidson is somebody who’s historically cited research that shows heavily resisted eccentrics can improve performance in dynamic actions. These concepts are important for both durability and rehab outcomes.
Isoinertial Resistance
Our flywheel guide is what you’ll want to check out for flywheel-based, isoinertial resistance.
Isoinertial resistance doesn’t rely on gravity for load and is relatively uniform. Isoinertial resistance is commonly applied with flywheel training, but some systems mimic that modality with biofeedback sensors and loading responses. Isoinertial resistance is about manipulating momentum and forces, not manipulating the gravitational responses of loads.
Isoinertial resistance can be of particular use at strengthening athletes’ ability to brake and better accept force, as well as strengthening the changeover abilities from eccentric to concentric.
An increasingly popular—and, to be honest, ideal—way of integrating this type of resistance is cueing athletes to intentionally yield (or “relax”) into the eccentric phase of the movement before putting on the brakes at a given joint angle and sticking the landing. Another good idea is having athletes intentionally yield into movements before concentrically exploding out of positions that correspond to sporting actions (as opposed to going and resisting full ROM).
Isoinertial resistance can be of particular use at strengthening athletes' ability to brake and better accept force as well as strengthening the changeover abilities from eccentric to concentric, says @RewireHP. Share on XIsotonic Resistance
Isotonic resistance is what we think of when we think of a typical resistance machine in virtually every big box gym across the world. Nautilus is who first introduced consumers to this type of resistance.
As we mentioned in version 1.0 of this guide, the term isotonic is very broad and this still stands. Thus, most machines and traditional equipment will provide some sort of isotonic stimulus. Isotonic is just creating a change in tension on muscle, and nearly any exercise outside of isometric training (a fixed, static contraction) will provide a dynamic contraction. Some muscle groups will co-contract or statically contract to stabilize a joint or transfer force, but most will lengthen and shorten during movement and training.
Generally, the isotonic resistance we’ll cover in the context of resistance training technology is air-driven resistance, where there is no inertial component present. Just about everybody will be familiar with Keiser Fitness, who functionally wrote the book on this type of resistance training for both strength and power adaptations.
Ballistic
One of the advantages with motorized equipment is the ability to control inertia. Unlike isotonic, air-driven systems with no inertial effect (like Keiser), solutions which are directly controlled by an electric motor can simulate a weight in a gravitational field during acceleration. Hence the inertial resistance, as well as the set load, must be overcome to move the simulated weight.
There’s nothing unusual with that, as a regular barbell or a weight stack acts in the same fashion. The interesting part is that during the deceleration of the movement, where a regular weight stack will provide very little resistance or even start to fly on its own in a fast deceleration. This is not very efficient training, is unpleasant, and can be a barrier to training explosive movements with regular weights. A motorized solution can, in contrast, apply resistance also in the deceleration phase; this means the athlete is always in contact with the load and can perform high speed multiple repetitions at a high velocity and change of direction frequency.
Collinear Resistance
Collinear resistance has become popular for its ability to guide improvements in both rehab and performance. Unlike other types of resistance traditionally seen in gym, collinear resistance can load omnidirectionally. This simply means it has the ability to load users in multiple directions, easily switching from loading the eccentric phase of a movement to another. It does this all while having the ability to provide multi-planar loading, as opposed to a comparatively more fixed up/down motion. This distinguishes it from cable- and gravity-dependent options.
The user has a high degree of freedom in both motion and speed, while each motion has data captured on it in real time. Research here is still fairly emergent; however, there is some positive research on omnidirectional loading and collinear resistance as it relates to pool training. That’s also something coaches will need to think about before investing in such a piece—if you have access to a pool, you can capture the benefits of omnidirectional loading with even more expanded movement pattern options. Equipment is optional, but effective, and can be had for mere hundreds rather than thousands of dollars. That said, some athletes—like baseball and volleyball players—will no doubt appreciate the collinear resistance with quantification metrics.
More resistance options exist, including vibration, accommodating methods, and assisted solutions that reduce the demand of gravity on conventional training. The main point is that outside of barbells, alternative forms of training exist and can provide powerful stimuli to athletes if used correctly. The main barrier for motorized resistance machines is the education gap and *some* outside tech companies thinking they’re coming in and disrupting performance when, in reality, they may not truly understand desired adaptations and how to go about stimulating those.
General Machine Design Factors to Consider
Safety is important, but should be a given at this point for any piece that makes it to market.
Coaches should also first run a logistical analysis and ensure that the tech they’re investing in matches how they coach. For example, if a tool requires such a learning curve that a coach will need to supervise the execution of exercises, then it may not scale well as a station in larger group settings. Be sure your investments match your workflow.
Will it be durable? There are multiple factors at play when companies design equipment in this vein—specifically, software and hardware considerations. Occasionally, a company will put a lot of thought and investment into one area (say software), meanwhile the hardware isn’t durable enough to stand up to the wear and tear of consistent gym use. It’s important to ensure what you’re buying is well-built and ideally has some type of repair support or warranty.
Coaches should first run a logistical analysis and ensure that the tech they're investing in matches how they coach—be sure your investments match your workflow, says @RewireHP. Share on XIn general, most of the manufacturers or providers of resistance technology struggle to have every facet of their equipment on par with industry standards. This is normal and far from ideal, but the gap is closing with every generation. In the past, equipment was dated and primitive, but now the same aerospace quality of design and engineering is available to the market.
The same rules and approaches in adopting more conventional strength training equipment apply here, too. Space, portability, workflow, scalability and even aesthetics all matter when making a purchase. A disconnect between designer and user frequently exists due to the fact few engineers have experience in the trenches coaching.
A final but important factor to consider is the idea that not all data provided by *some* of these machines is high quality (or even necessary). Some provide useful data that could help identify strength asymmetries, quantify load progressions, and more. However, just be wary of valuing data over results and don’t get lost majoring in the minors. At the end of the day, the adaptation is what we’re chasing more than anything else.
Resistance Technologies Worth Your Time & Investment
Some giants exist, but most of the resistance options are small companies that are highly specialized. One obvious fear of teams and facilities is that a new company will form and go insolvent after they’ve invested heavily in the new technology. While that can happen, it’s most likely that even after a company dissolves, a third party can still support most equipment. Several companies have grown to be major players in the fitness and performance space, and several have existed for more than 20 years.
Here are the new and leading options that are good examples of what the scope of the market can offer. Each company has strengths and specializations that may or may not fit your specific needs.
1080 Motion – 1080 Motion makes the Quantum and the Syncro, two resistance machines that both use a patented robotic mechanism of force transmission. Each system provides an impressive set of modes of resistance and operates through a touchscreen, which also synchronize with a cloud data storage. The Quantum is similar to a cable column, while the Syncro is essentially two Quantums fused with a squat rack. In addition to the resistance machines, the Swedish company provides a resisted sprint machine, the 1080 Sprint, that provides both resisted and assisted options to athletes. Team sport facilities, rehabilitation clinics, and research institutions all use 1080 Motion equipment. The machines feature isotonic resistance and provide every common resistance type, also include a vibration setting for those looking to incorporate pulsating force; additionally, they offer the ability to control inertia, allowing for ballistic training.
ARX – The original player in the maximal strength, adaptive resistance exercise tech market, ARX (Adaptive Resistance Exercise) has mostly been popular in the private training space for its ability to consolidate the time needed to be spent on maximal strength as well as its ability to quanitfy user’s progress. Whereas Speede consolidates as many movements as it can into one, ARX has two different machines that collectively net users a multitude of resistance patterns (e.g., leg press, chest press, pulldown, and more). The technology is impressive and they are the O.G. player in this space, but is fairly cost-prohibitive to integrate as one instrument in your orchestra—because of this, it’s generally the centerpiece of most gyms that adopt it. Like Speede after it, ARX also boasts efficiency in strength training as one of its main talking points.
Keiser – Keiser has long stood at the top of the resistance training technology space. While some of these other options are great investments, you’ll still no-doubt find yourself wanting at least certain Keiser machines in your facility. Keiser has continued to refine its product for greater durability, smooth feel, and ergonomics. They’ve come out with a few new pieces and continued to push the education front. Based in Fresno, California, the company is a leader not only in technology-driven resistance machines, but in the global fitness market as a whole. Keiser uses a pneumatic pressure option, basically taking air and converting it to isotonic resistance using motorized pumps. The resistance also provides a slightly different load than traditional resistance equipment, making it ideal for not only strength, but also for power development. Keiser has spread to all areas of performance, ranging from seniors to elite sport, making them an established brand over the last few decades. The most important market is the general fitness space, and Keiser leads here with an array of models covering total body as well as specialized pieces. Each machine uses a digital screen to show instant feedback and precise estimations of resistance, ranging from therapeutic loads to massive forces for elite athletes. Keiser has a strong presence in the cycling industry, with a very popular line of indoor bikes.
OHM Dynamics – OHM is a new face since the last edition of our Buyer’s Guide. They offer the OHM Run—a large, vertically-stacked machine that looks something like a larger cable pulley system. Their unique feature is the user’s ability to control their own resistance and adapt this to their own capabilities. This can help with both traditional strength work, though it provides more sensory feedback, and also be set slower with capabilities for more load. This makes OHM ideal for things like loaded movement training, as well as using load as a “teacher” to help coordinate movement with the appropriate target tissues being recruited as a set. This can also help promote intent in movements such as resisted sprint marches, backpedals, and much more.
Boston Biomotion – Boston Biomotion had just dropped the Proteus the last time this guide was released and the technology has only continued to gain traction in both the strength & conditioning and rehab fields. Originally founded at MIT, they now operate out of New York City. Boston Biomotion’s flagship product is the Proteus, which resembles a giant arm and provides a radical approach to resistance. Termed “collinear,” the resistance is a true 3-D force tool and entered the market in 2017. The system has won innovation awards and is currently a leasing solution for both rehabilitation and general training. The software is complete with reporting, instant feedback, and data export features. Similar to cable motions, but with concentric-only resistance in multiple plains, the system is ideal for those wanting high speeds and high ranges of motion. Unsurprisingly, the machine has gained a ton of popularity on more transverse-driven sports like baseball.
Beyond Power – The company beyond the VOLTRA I exploded onto the space in the last year or so. Armed with an incredibly smart, highly responsive team that’s unparalleled in terms of its ability to listen to the customer, it’s no surprise that they’re gaining a ton of traction. Similar to Keiser, the B.P. team feels as much “designed by coaches for coaches and athletes” as anything else in the space. Their initial product offering—the VOLTRA I—is a Swiss Army Knife of resistance training tech, featuring an assortment of modes that mimic all types of stimulus. These include resistance bands, Vertimax-type resistance, traditional isotonic cable resistance, chain resistance, eccentric overload, maximal strength adaptive resistance (a form of isokinetic resistance), and isometric options. The machine is about half the size of a shoebox, highly portable, has horizontal and vertical vector mounts, offers up to 200lbs worth of resistance yet can be synced with another device to get that number up to 400.
Biodex – One of the isokinetic training pioneers, Biodex continues to go strong. Although that nomenclature has since brought about spinoffs, Biodex remains the leader in the original form of isokinetics they and Gideon Ariel brought forth. This New York company is world-renowned for isokinetic testing, and also involved in other areas of assessment. Biodex has been in business for over 60 years and is the largest of all the brands listed. While they are the leader overall with market saturation, they have not made many changes in their equipment over the years and it’s more aimed at research and rehab than performance training. However, the data integrity is especially high for teasing out asymmetrical strength deficits and it’s considered research-grade in the industry. Finally, most of the equipment is designed for general rehabilitation assessment, not for progressive return to play, like newer companies. Dynamometers are testing tools, not training equipment for actual closed chain exercises, as those are open chain devices that isolate muscles and joints.
Exerbotics – The Tulsa company provides a small line of commercial equipment for those looking for eccentric training, as well as iso-velocity resistance. Exerbotics’ equipment manipulates the resistance and speed of movement, with fixed mechanical vector paths based on user height. The specialized equipment solutions are unique in that they use linear actuators, not pneumatic or cables. They boast a 10-year durability standard and include readouts with each system. Exerbotics equipment has both closed-chain and open-chain movements, including an innovative hamstring system called the CrossFire.
FastTwitch Isokinetics – Formerly TEKS, this Australian company has an isokinetic solution in two full lines of machines, one for performance and the other for rehabilitation testing and training. Similar to Biodex and Exerbotics in technology and design, the company’s products are available outside of Australia and appear to be viable options for professional teams such as the Chicago Bulls, Sacramento Kings, and Dallas Mavericks. The company is also a provider of other equipment, including traditional fitness machines and supplies.
Sports Science Lab – A small company that was formerly based in Southern California, SSL is currently the only company offering the aforementioned type of concentric-only, fanblade-based isokinetic resistance. The ISO—as their machine is known—is popular for both rehab and performance.
X-Force – The final company on the list is from Sweden and offers a complete line of eccentric training devices. While X-Force uses weight stack loading, they add in increased resistance on the eccentric portion of their lifts. The extensive line includes over a dozen different machines, all targeting muscle groups for an approach to fitness similar to Nautilus from decades ago. The company provides customized options like color choice and includes business opportunities like licensing options.
Parting Shots
Because this space is fairly new, it’s challenging to give a ton of wide-sweeping advice without sounding too vague and abstract.
Expect innovation to continue and for more emergent technologies to appear here, with AI potentially playing a role in some software elements.
But the biggest takeaways that apply to all types of resistance training technology are to first understand what adaptation a technology is providing (and is it something you need and can’t get as easily elsewhere). The next step is to ensure it’s something that’s necessary to better perform your job as a coach and isn’t just trying to project an image of forward-thinking to potential clients. Many coaches can unfortunately turn these types of investments into something of a “space race,” thinking they have to keep up rather than making meaningful investments that deliver better athlete outcomes.
Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF