It is often said that lean mass levels should be considered a fifth vital sign in medicine.But building and maintaining lean muscle isn’t important only for the aging population.It’s also important to athletes for the performance of their sport and to the recreational fitness enthusiast who wants to maintain a healthy metabolism and aesthetic physique.In today’s society, body image is a big deal. And as a significant contrast to the Hollywood stars of the mid-20th century who looked like they’d never stepped foot in a weight room—or to the skinny-chic models and boy-banders in the 90’s and early 2000’s—today’s preferred body type in almost every arena includes lean mass.It’s not just for bodybuilders anymore. Or should I say, bodybuilding isn’t just for bodybuilders anymore? Optimized levels of lean mass are essential to the mental and physical well-being of both men and women.

Do We Know What Makes The Muscles Grow?

Well, after over a century of study, it’s been largely boiled down to a few “active ingredients” that we can apply to our workouts. And those active ingredients are Mechanical Tension, Muscle Damage, and Metabolic Stress.Briefly, Mechanical Tension can be thought of as the amount of resistance the muscles encounter. The “weight on the bar,” in other words.Muscle Damage refers to the muscle fibers’ micro-tears during resistance exercise, most notably in the eccentric phase of motion as the active muscle lengthens.And Metabolic Stress includes alterations in the hormonal milieu, cell swelling, free-radical production, and increased activity of growth-oriented transcription factors.When considering these three elements to the muscle-building stimulus—and considering how ARX compares to gravity-based forms of resistance—it becomes more and more obvious that the best tool for this job is one that can maximize all three without compromise.

Mechanical Tension

As you can see from the graphic above, Mechanical Tension is King. It not only affects the other two elements, but it has the greatest effect on your muscle growth.For example, in a meta-analysis by Brad Schoenfeld, “a trend was noted for the superiority of heavy loading” with respect to muscle strength and hypertrophy.We also understand that only maximal load—but not submaximal load—resistance exercise increases testosterone.The point is that if you want to maximize all the factors necessary to stimulate your body to synthesize new muscle tissue, you’re going to want to maximize “heavy resistance” and mechanical tension.With weights, you are very limited in terms of how much mechanical tension you can apply to your muscles, and this is because weights do not adapt to your changing levels of strength.You have to underload yourself when using a weight purposely, and this underloading of the muscles limits the effectiveness of weight lifting.Your strength changes in three ways during exercise:

‍● From the beginning to the end of a set: you have to purposely underload yourself so that your set can last longer than one repetition. If you appropriately load the first rep, you cannot complete another, and so you must reduce the weight you’re using to accommodate additional reps.

‍● From the concentric phase to the eccentric phase: you can lower—under control—more weight than you could have lifted in the first place. If you appropriately load your eccentric (lowering) phase, you will be unable to lift the weight back up. So you have to reduce the weight you’re using to accommodate the weaker concentric (lifting) phase.

‍● From joint angles of mechanical advantage to joint angles of mechanical disadvantage: we’re stronger at the top of a squat than at the bottom, stronger at the top of a bench press than when the bar’s on your chest, and so on. If you appropriately load your strongest range of motion, you will overload your weakest range of motion. So you must reduce the resistance to the amount that you can move through your weakest positions.Each one of these elements requires you to purposefully underload yourself.You could be doing your maximum all the time, but because of the tool you’ve chosen, you now have to voluntarily use a lesser weight that you can move through space from the beginning to the end of the set, through the eccentric AND concentric, and through your weak joint angles as well as your strong ones. ARX’s Adaptive Resistance™ solves each one of these problems, allowing you to exert at the maximum forces of which your muscles are capable:

● Right from the first rep, and for as many reps as you like

● During your strongest eccentric max contractions and your weakest concentric contractions● At your strong joint angles as well as your weak ones. But regardless of the tool, you’re using, mechanical tension should be a priority of your training for mass.

Muscle Damage

The short story here is that resistance exercise physically tears muscle fiber, and the body uses macrophages, satellite cell activation, proliferation and differentiation, and other growth factors to build the muscle fibers back up again.The primary drivers of microtrauma to the muscle fibers are eccentric contractions. As the actin and myosin filaments inside the muscle slide past each other to facilitate contraction (the concentric phase), their cross-arms interact with each other in a way that keeps them intact.However, as the actin and myosin filaments resist being elongated (the eccentric phase), they suffer damage when those cross-arms hang on for dear life as they’re ripped from their moorings on the filaments.And the greater the mechanical tension during these eccentric contractions, the greater the degree of muscle damage, and the greater the body’s response is in terms of stem cell/satellite cell recruitment and salutary inflammatory response.As seen previously, ARX’s Adaptive Resistance™ exceeds the capacity of weights to maximally load the eccentric phase of muscle contraction.But regardless of the tool you’re using, muscle damage should be a priority of your training for mass.

Metabolic Stress

Conversely, concentric contractions produce the greatest metabolic stress inside the muscle since muscles rely on anaerobic glycolysis for ATP production, which results in the subsequent buildup of metabolites such as lactate, hydrogen ions, inorganic phosphate, creatine, and others.So the more mechanical tension we can get during the concentric phase, the more robust the metabolic stress response will be.With weights, the only time the weight you’re using is a perfect match to your ability to concentrically produce force is when you’re at total muscle failure. That is when you’ve lifted and lowered the weight enough times that you’re unable to complete another repetition.The problem is, you were underloaded for each rep it took you to get to that point.ARX’s Adaptive Resistance™ allows you to exert maximally during every concentric, without limitation. This means that metabolic stress is maximized in the process.But regardless of the tool you’re using, metabolic stress should be a priority of your training for mass.

‍Additional Read: The Adaptive Triangle - Adjust Your Workout Intelligently

Wrapping Up

So there you have it. If you are looking to build or regain muscle mass, your focus should be on mechanical tension, muscle damage, and metabolic stress.Bodybuilders, physique competitors, athletes who need to add mass, and elderly people who need to regain lost lean mass can benefit from a technology that maximizes the muscle growth stimulus.So if body composition and increased muscle mass are priorities of your training—and they should be—ARX’s Adaptive Resistance™ outperforms the competition.