- October 8, 2021
Why Variable Resistance was Underestimated
The following is an excerpt from the Wall Street Journal best-selling book, Weightlifting Is a Waste of Time.
Even though John’s original research centered on stimulating bone growth, his findings also set the stage for a new and aggressive way to look at human strength capability. His conclusions had incidentally quantified the absolute maximum outputs for humans engaging their major muscle groups. These maximum force production capacities were pinpointed in a multitude of different positions throughout the range of motion for several different standard exercises.
Bone loading is induced by and dependent on the supporting musculature, and he’d already proven muscles could withstand far greater forces than weightlifting can generate. Based on this discovery, we split our focus between bones and muscle. We started by taking a deep dive (as researchers, we call this a literature review) into the ways in which variable resistance had been applied in the world of exercise.
After culling through the available studies, we located numerous ones identifying variable resistance’s superiority to weightlifting. This held true whether the subjects were athletes or sedentary, old or young. All of which led us to wonder: why was everyone still lifting weights when variable resistance had been proven more effective at developing musculature?
One of the most compelling variable-resistance studies was carried out at Cornell University. Participants were recruited from the men’s basketball and wrestling teams, as well as the women’s basketball and hockey teams. The student-athletes were tested both pre- and post-experiment for lean body mass, one-repetition maximum back squat and bench press, and peak and average power.
Each was then randomly assigned to a control group or an experimental group. The control group continued an existing weight training protocol using standard barbells loaded with iron plates. The test group did an identical workout on the same equipment, only with bands added to the barbells. The average resistance was kept the same for all participants, so the experimental group lifted less actual “iron” to make up for the added resistance provided by the bands.
After seven weeks, the group using variable resistance recorded twice the amount of improvement on bench press single rep max than the control group and triple that on squats, as well as posting a three times greater average power increase. Even though the student-athletes were all performing the same exercises, participating in the same protocol, and lifting the same relative amount of weight, the variable-resistance group experienced significantly more strength gains than the weightlifting-only group.1
Variable Resistance Studies Done With Elite Athletes
NOTE: Pay close attention to the studies done with elite athletes, even if you are not one. Elite athletes have much more trouble building muscle than beginners to strength training. Therefore, when a study is done with them, it is a more important indication of what actually works. They are also more likely than other test groups to actually follow the protocol because they are more serious about their progress. In addition, most elite athletes participating in research are members of college sports organizations that do performance-enhancing drug (PED) testing. Conversely, many studies using average recreational exercising populations allow for self-reporting of exercises and nutrition, and the average population is not always honest about deviating from the prescribed exercise protocol or diet.
The effects of variable resistance on the maximum strength and power were tested using Division I football players. Here, volunteers from Robert Morris University were divided into three groups: One training with elastic bands, another with weighted chains, and the last using a traditional bench press. Each participant did a speed bench press and one repetition maximum test pre- and post-experiment. After seven weeks, the groups training with elastic bands and weighted chains—the athletes exercising with variable resistance—showed greater improvements than the ones working out on conventional weightlifting equipment.2
Another study of elite athletes sought to determine whether higher loads of variable resistance resulted in bigger strength gains. Division II basketball players were recruited during the off-season to complete this research. Power development, peak power, strength, body composition, and vertical jump height were measured pre- and post-experiment. Participants were then divided equally into two groups. One added variable resistance to their training once weekly while the other continued doing traditional weightlifting only. At the end of the study, the athletes doing variable resistance posted significant improvements in speed, strength, vertical jump, and lean mass over the control group.3
Still more proof that variable resistance builds strength faster and more effectively than traditional weightlifting comes from a study of elite youth rugby players. The participants were tested for velocity and power on bench press before, beginning, and at the end of the study. A control group used free weights only while the other received 20 percent of their prescribed load on bench press from elastic bands. At the end of six weeks, the group using variable resistance showed bigger increases in their velocity, power, and one rep max on bench press than the free weight-only group.4
Yet another study, this time involving Division II baseball players, showed variable resistance provided greater rates of strength gain as measured by improvements at standard bench pressing. Even more importantly, participants doing variable resistance had less shoulder stress, enabling them to train further, harder, and continue to gain muscle/strength at a faster rate than their peers due to the lack of neural inhibition and reduced risk of joint injury.5
In 2018, a group of professional rugby players participated in a randomized, controlled trial. This study measured explosive pushing power, something of critical importance in the sport. With only seven days of training time, the variable-resistance test group had statistically significant increases in pushing power, whereas the control group did not.6
Andersen, Fimland, and other researchers conducted two studies (2016/2019) evaluating different levels of variance with “high-level strength athletes, performing two different important multi-joint lifts, the squat and the deadlift.” These assessed muscle engagement and rate of muscle recruitment by analyzing electrical activity through electromyography. As they began to raise the ratio of peak force in the strong, or impact-ready, range of motion, researchers noted increasing muscle engagement.7,8 In other words, the greater the variance of resistance they used, the greater the peak muscle activation.
The most recent study with elite athletes is perhaps the most shocking in terms of how far behind the rest of the world is in terms of using variable resistance to build muscle. In a survey of Norwegian powerlifters, 76.9 percent reported using variable resistance as a part of their regular training program.9 Those who follow international powerlifting will know that Norway may be one of the strongest nations in the world per capita.10
At this point, John knew some researchers were working on closing the gap between random levels of variance and the absolute maximums seen in his 2015 research.
Variable-resistance Studies Done With Semiathletic Individuals
The studies using elite athlete populations add strength to the library of variable-resistance literature in general. Almost identical results have been seen using more “average gym-goer”-type individuals.
One such study had two groups exercise, one using variance and the other standard weights. Cronin and researchers discovered greater EMG activity during the later stages (70-100 percent) of the eccentric phase (meaning the lowering of resistance) of the banded squat when compared to a standard weight squat. Their ten-week analysis showed banded resistance training led to significant improvements in lunge performance (21.5 percent) compared with control groups. In this study, the variance group outperformed the control by 21.5 percent in ten weeks.11
A 2019 study by Smith et al. looked at sensory reflex performance after a multi-week exercise program that compared a variable-resistance group to one using standard weights. The variance group exhibited greater reflex improvements, and the study concluded: “variable resistance training elicited greater reflex adaptations compared to dynamic constant external resistance.”12 This indicates that speed improvements could result with variable resistance, perhaps because more muscle tissue is activated. Further, if more muscle tissue is able to balance an individual as they move, this is a direct driver of one’s ability to sprint with greater proficiency. Consistent with this hypothesis, another 2019 study showed variable resistance was able to activate more muscle and positively influence jump performance after just one intervention, but the standard weight training control group did not demonstrate any influence for the same kind of test.13
As mentioned earlier, to gain strength and muscle size there is no getting around HEAVY. Although what is considered heavy is different for every individual, most studies have seen sixty seconds as an optimal time under tension before fatigue. Obviously with variable resistance, you benefit from more force than you can achieve with ordinary fixed weightlifting for any given exercise time. But don’t just take our word for it. Instead, consider this quote from yet another relevant study on variable resistance: “Squatting with elastic bands facilitates more weight used and time under muscle tension.”14
Variable Resistance and Untrained Individuals
We’ve often encountered the objection that the research just cited only proves variable resistance works for athletes. To answer that, we’ll begin by pointing out the obvious: The benefits of exercise enjoyed by athletes are available to non-athletes as well. In fact, deconditioned individuals may respond even more quickly to a new exercise protocol because there is greater room for improvement.
We can also point to existing variable-resistance research on non-athletes demonstrating similar efficacy to studies done on athletes. For example, forty-five middle-aged, sedentary women were tested on knee push-ups, sixty-second squats, and body composition. They were then divided into two groups, one using elastic bands to exercise and the other weight machines. All performed the same exercises and number of repetitions, as well as used the same perceived effort, twice a week for ten weeks.
At the end of the study, both groups recorded less body fat, more lean mass, and increased reps for push-ups and squats.15 Because very low-resistance bands were used, results were fairly similar between the variable-resistance and weight-training groups. But even at very low levels that reached nowhere near muscular capability, variable-resistance training proved quite effective.
Another recent study of thirty-eight post-menopausal women showed training with bands not only significantly lowered weight and waist circumference, but also improved cardiovascular profiles and cholesterol indicators. The control group that didn’t do any exercise over the same one-year period showed significant increases in their weight and waist circumference.16It’s safe to say that most of us want to be leaner and healthier, not fatter and more prone to heart problems. Variable resistance is a proven method of achieving these goals.
Other research shows variable resistance offers a low joint stress method for facilitating greater muscular engagement. A study involving people with an injured anterior cruciate ligament found that “anterior cruciate ligament strain values obtained during squatting were unaffected by the application of elastic resistance intended to increase muscle activity."17 This is consistent with our hypothesis that variable resistance permits exercisers to load their muscles with greater forces while reducing stress on joints.
If you don’t belong to any of the demographics we’ve discussed so far, take heart. We haven’t encountered any test population that doesn’t seem to benefit from variable-resistance training. Even older adults (60+) have been tested and show similar results to both the elite populations and more average exercisers.18 Variable resistance works no matter your current conditioning, age, or sex. The principles it follows and muscle tissue it stimulates remain the same.
Isolating Variable Resistance as the Key Factor
Many of the studies we just discussed compare standard weightlifting protocols to those including some level of variance, provided by either rubber/latex banding or other methods. For example, a given control group may have exercised with weights only and their corresponding test group may have used a lighter weight with elastic banding connected to the weight bar to offer a small level of variable resistance to the entire exercise movement. In every test of this kind cited, the variance group outperformed the static resistance one. So, what is the critical variable that changed—the variance or something about static resistance? The obvious answer is variance.
Other studies had test groups using bands only, with no fixed weights at all. In those cases, we also observed the test group using variable resistance outperforming the control group using fixed weights. In these cases, the situation is even simpler. We don’t have to ask what factor is more important, we just have to look at what methodology yielded superior results—and that is consistently variable resistance.
In all cases, the group that included variance performed better, became stronger, and grew muscle mass faster. So what’s more important? Weights or variance?
A gym in Ohio that trains competitive lifters applied variable resistance to its lifting protocols and ended up breaking over 140 world records. When asked how they were doing it, the answers were a bit convoluted. Perhaps they were protecting their method for business reasons, to keep an advantage. But aside from this outlier, why didn’t the world immediately jump on variable resistance after most of these studies were published?
Research and Innovation Are Not the Same Thing
John actually had one of the researchers referenced in this chapter approach him at the National Congress of the American College of Sports Medicine (ACSM) to share his excitement over the technology/products John had been working on. Then he asked, “How did you figure it out?” John was confused because the real question in his mind was, “How did the rest of you guys NOT figure this out?” Of course, he never said this, and ended up buying a round of drinks for the other researchers instead.
There is a tremendous difference between research and innovation. The job of a researcher is to test a concept that might be slightly (or greatly) different from the standard approach to a given objective. In the context of exercise science, they are often testing a concept that someone else invented, which has already been used to some extent in practice. Then they test the two concepts and control for outside variables that might skew the data one way or the other. The conclusion to the test involves calculating if there was a statistically significant difference between the two data sets and commenting on other observations that may have been made during the study, which can enhance everyone’s understanding around that particular subject matter.
Notice that nowhere in this process is the researcher mandated to create anything or consider how their research findings might be used in the process of product development. In the variable resistance field, for example, a 2016 study concluded that variable resistance (or as the authors described it, “accommodating resistance”) would be useful for improving the training efficacy of powerlifters, bodybuilders, and athletes.19 The conclusion never segued into product design planning, because that’s just not what researchers typically set out to do.
An obvious exception to the above assessment of researchers would be R&D engineers employed by large companies for the express purpose of performing research with the goal of product development. But even when you include this group, successful research-driven product innovation is surprisingly rare. How long before the advent of high-quality consumer digital cameras was the first prototype developed in an R&D setting? The answer is about thirty years. In fact, Eastman Kodak invented the functioning digital camera in 1975 (yes, that Kodak) but they initially decided not to develop it into a product. Because there aren’t that many people out there looking to challenge convention and take the risks inherent to innovation, they waited decades before turning that research into an actual product.
As you likely know, eventually other businesses developed this technology on their own, and competition from digital cameras made by other manufacturers drove Kodak to file for bankruptcy in 2012. This is just one example of the gap between research and actual product development. It strongly suggests there are other areas of academic understanding right now that do not coincide with, and are more advanced than, the products or methods people generally use.
These are innovations waiting to happen.
Why the Untapped Potential?
An absolutely critical limitation to developing the ultimate variable-resistance system was that the studies were lacking data describing the optimal amount of variance to use. Meaning, some studies used X amount of weight in the weak range, then 1.2 X amount of weight in the impact-ready/stronger range. Other studies used slightly different ratios, and even still, some other studies didn’t even bother to fully quantify the degree of variance they were using. The lack of hard numbers and ratios for the maximum amount of desired variability in a variable-resistance protocol likely deterred innovators from developing a real variable-resistance product. We use the word “real” because we do acknowledge there are a number of junk/fake fitness products that use elastic banding, but these can deliver only five to thirty pounds of force, which is not relevant for any type of strength application.
For John, developing the ultimate variable-resistance system was straightforward, given the circumstances. He had already invented the world’s most powerful bone-density treatment device, so he wasn’t afraid of taking the risks in creating a new concept. Most importantly though, the bone density data allowed him to start with the answer to a question no one had yet asked. When the data was collected in the 2015 London hospital study, he knew he was the only one who could see just how far variable resistance could be taken.
No one else in the fitness world had this data and an understanding of strength adaptation. Only John did. With this knowledge, he forged ahead.
Andersen, CE, Sforza GA, & Sigg JA. (2008). The effects of combining elastic and free weight resistance on strength and power in athletes. The Journal of Strength and Conditioning Research, Mar; 22(2): 567-74. ↩︎
Ghingarelli JJ, Nagle EF, Gross FL, Robertson RJ, Irrgang JJ, & Myslinski T. (2009).The effects of a 7-week heavy elastic band and weight chain program on upper-body strength and upper-body power in a sample of division 1-AA football players. The Journal of Strength and Conditioning Research, May; 23(3): 756-64. ↩︎
Joy JM, DeSouza EO, Lowry R, & Wilson JM. (2013). Performance is increased when variable resistance is added to a standard strength program. The Journal of Strength and Conditioning Research, May; 30(8). ↩︎
Rivière M, Louit L, Strokosh A, & Seitz LB. (2017). Variable Resistance Training Promotes Greater Strength and Power Adaptations Than Traditional Resistance Training. The Journal of Strength Conditioning and Research, April; 31 (4): 947–955. ↩︎
McCurdy, K, Langford, G, Ernest, J, Jenkerson, D, and Doscher, M. (2009). Comparison of chain- and plate-loaded bench press training on strength, joint pain, and muscle soreness in Division II baseball players. Journal of Strength and Conditioning Research. 23: 187 195. ↩︎
Godwin, M. S., Fernandes, J. F., & Twist, C. (2018). Effects of Variable Resistance Using Chains on Bench Throw Performance in Trained Rugby Players. The Journal of Strength & Conditioning Research, 32(4), 950–954. ↩︎
Andersen, V. Fimland, M. S., Kolnes, M. K., Jensen, S., Laume, M., & Saeterbakken, A. H. (2016). Electromyographic comparison of squats using constant or variable resistance. The Journal of Strength & Conditioning Research, 30(12), 3456–3463. ↩︎
Andersen V, Fimland MS, Mo D-A, Iversen VM, Larsen TM, Solheim F, et al. (2019) Electromyographic comparison of the barbell deadlift using constant versus variable resistance in healthy, trained men. PLoS ONE 14(1): e0211021. ↩︎
Shaw, M. P., Andersen, V., Sæterbakken, A. H., Paulsen, G., Samnøy, L. E., & Solstad, T. (2020). Contemporary Training Practices of Norwegian Powerlifters. Journal of Strength and Conditioning Research, 10.1519/JSC.0000000000003584. Advance online publication, [https://doi.org/10.1519/ JSC.0000000000003584]. ↩︎
Contreras, B. (2017, January 2). An interview with Marte Elverum - A Women’s Norwegian Elite Powerlifter. Retrieved from [https://bretcontreras.com/an-interview-with-marte-elverum-a-womens-norwegian-elite-powerlifter/] ↩︎
Cronin, J, McNair, PJ, and Marshall, RN. The effects of bungy weight training on muscle function and functional performance. The Journal of Sports Science, 21: 59-71, 2003. ↩︎
Smith, C. M., Housh, T. J., Hill, E. C., Keller, J. L., Anders, J. P. V., Johnson, G. O., & Schmidt, R. J. (2019). Variable resistance training versus traditional weight training on the reflex pathway following four weeks of leg press training. Somatosensory & Motor Research, 36(3), 223-229. ↩︎
Mina, M. A., Blazevich, A. J., Tsatalas, T., Giakas, G., Seitz, L. B., & Kay, A. D. (2019). Variable, but not free-weight, resistance back squat exercise potentiates jump performance following a comprehensive task-specific warm-up. Scandinavian Journal of Medicine & Science in Sports, 29(3), 380-392. ↩︎
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Gomez-Tomas C, Chulvi-Medrano I, Carrasco JJ, & Alakhdar Y. (2018). Effect of 1-year elastic band resistance exercise program on cardiovascular risk profile in post-menopausal women. Menopause, September; 25 (9): 1002-1010. ↩︎
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