Jaquish Biomedical

What’s the science behind X3?


More Information About The Science Behind X3#

In 2015, Dr. Jaquish authored a research protocol for a London-based hospital to perform a study on human performance and bone. In that study, we saw that individuals could create tremendous forces through the body when isolating the impact-ready range1. When compared to the American College of Sports Medicine database, these forces were 7-times greater2. After making this discovery, we realized that lifting weights was possibly the worst way to trigger muscle growth. We then designed a system to help people leverage these new scientific findings to get the best workout available. While using the prototype, Dr. Jaquish gained 30 lbs of muscle and lost body fat at the same time. NOW there is a FAR better way to achieve your fitness goals.

Chart showing variable resistance

X3 Bar is the best way to work out, and we will make that case with additional peer-reviewed references from other studies in the following paragraphs. You will also see some articles at the bottom of the page, published in the popular press, extolling the advantages of variable resistance.

Variable resistance (such as X3) creates muscle gains faster than conventional training. We quote from a study on Cornell Student-Athletes:

Compared with C(control), improvement for E (elastic) was nearly three times greater for back squat (16.47 +/- 5.67 vs. 6.84 +/- 4.42 kg increase), two times greater for bench press (6.68 +/- 3.41 vs. 3.34 +/- 2.67 kg increase), and nearly three times greater for average power (68.55 +/- 84.35 vs. 23.66 +/- 40.56 watt increase).3

So, when compared to regular weight training, variable resistance training led to greater gains in one-rep max, and greater gains in average power, for the time period tested. This may be one of the most profound discoveries in the history of sports performance science. You may notice that the elastic group in this study did perform combined variable resistance and resistance training, since the athletes used bars and plates attached to elastic bands, so while the resistance varied, they always had to lift the bar/plate/other mechanical assembly.

Although the X3 Bar is not very heavy, we provide a very similar experience, since the product is composed of a bar, and a plate. We also advise, for exactly this reason, that X3 is used with constant tension during exercises. Make sure the band always has tension on it for the entire range-of-motion for each exercise.

When used this way, X3 Bar replicates the study conditions that led to increased muscle growth very effectively, since that constant tension always provides a baseline level of resistance as there would be with a weighted barbell, and then that resistance increases as one goes through the range of motion. After all, muscle tissue certainly can’t tell if a force is applied by an elastic band, or gravity acting on an iron mass.

Variable Resistance (such as X3) shows greater anabolic hormone responses over conventional weight lifting4. Variable resistance provided a greater increase in serum Testosterone and Growth Hormone than regular weight lifting.

X3 Makes (High Intensity) Variable Resistance Accessible: As we mentioned, the variable resistance component of an X3 workout is derived from the bands. You may very reasonably be wondering “Why not get just the bands?”. Because with X3 Bar, you can double over a heavy duty band, and perform an exercise at over 600lbs of force. As best we can tell, that’s just not possible with the band twisting one’s ankles, and applying all that torsion to one’s wrists. Not only is there a risk of injury, but the body reflexively limits muscle activation when this kind of discomfort exists, in a protective process called neural inhibition.

With X3 Bar, you avoid these limitations and that lets you lift heavier, and reduces the risk of joint damage. With X3, you gain a normal barbell interface, and you can perform the same lifts you would have with conventional weights, but now with the benefits of variable resistance. Another key factor is that one of the most compelling pieces of research on variable resistance (which showed greater gains in the variable resistance group, compared to the conventional weight group), used elastic bands attached to bars and plates, not elastic bands in isolation.

We set out to closely replicate the experience shown in the scientific study to allow X3 users to train with greater force to trigger greater muscular gains.

No, you don’t have to be a “Student-Athlete” to use variable resistance (Obviously?): In talking with people about the Cornell Athlete Study, we encountered the baffling objection that “variable resistance training only offered so much improvement because the athletes were already so highly trained”. We’re unfamiliar with that supposed principle of athletics, where it gets easier to improve once you are already very highly trained. Regardless, there is research on a middle aged, sedentary population, where even low intensity elastic band training was found to be at least as effective as weight training.5

No, there are not secret benefits when attempting to train heavy in weak ranges of motion: Training with variable resistance also gives you more force where you can actually recruit muscle tissue. Again, people confronted us with the highly unexpected allegation that “the weakest range of motion is where you really train the muscle”. This is totally untrue. If we look at research into muscle recruitment (potentiation) during maximum effort bench press exercise, we find that in the weakest range of motion, “the sticking point”, failure is not caused purely by mechanical disadvantage, but rather by the fact that muscle recruitment drops sharply as measured by electromyography.

As one study postulates, the sticking point in a weak range of motion occurs due to “diminishing potentiation of the contractile elements during the upward movement together with the limited activity of the pectoral and deltoid muscles”.6 What the researchers observed is that in the weakest ranges of motion, under high loads, the exerciser cannot recruit nearly as much muscle tissue as they can elsewhere in the range of motion. This is probably a protective feature of the nervous system, meant to prevent a person from injuring their joints by applying too much force to them while in an awkward position.

But regardless, brief reflection on this issue should tell us that if we cannot use the nervous system to obtain high levels of muscle tissue engagement during high load events in a weak range of motion, that muscle tissue is probably not getting much training benefit from that part of the exercise.


  1. https://www.omicsonline.org/open-access/axial-bone-osteogenic-loadingtype-resistance-therapy-showing-bmd-andfunctional-bone-performance-musculoskeletal-adaptation-over-24-weeks-withpostmenopausal-female-subjects-2329-9509-1000146.php?aid=58088 ↩︎

  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4139760/ ↩︎

  3. https://www.ncbi.nlm.nih.gov/pubmed/18550975 ↩︎

  4. https://www.ncbi.nlm.nih.gov/pubmed/20473217 ↩︎

  5. https://www.ncbi.nlm.nih.gov/pubmed/18714245 ↩︎

  6. https://www.ncbi.nlm.nih.gov/pubmed/20373201 ↩︎