ARX vs. Pneumatic Resistance
// BY JIM KEEN
How is this better than the pneumatic or hydraulic machines?
Can ARX do what they can do?
Answer: Of course! There is no result possible from the use of pneumatic resistance devices that cannot be matched and surpassed—more safely and more time-efficiently—through the use of ARX technology.
For reasons you’ll see below, however, the reverse is not true. It turns out that there are several things ARX makes possible that cannot be matched by any amount of work on a fluid-resisted (air/water) device.
Mismatched Resistance < Adaptive Resistance™
The main principle of resistance exercise is that the target muscles are made to contract against a resistance for the purpose of delivering a stimulus to the target muscles.
Any time there is a difference between the momentary strength of the muscles and the magnitude of resistance against which the muscles are made to contract, we can say that a mismatch has been created between the two.
If the chosen resistance is below the momentary strength capacity of the muscles, this represents an inefficiency. More sets, more reps, and an overall greater time commitment are required to accumulate the desired workout volume because the mismatch has under-loaded the target muscles.
Conversely, if the chosen resistance is above the momentary strength capacity of the muscles, this represents a serious risk of injury. An injury is produced when the body encounters a level of force that exceeds its capacity to absorb that force.
This excessive force happens either through the inappropriate selection of resistance in the first place, or through the application of dangerous magnitudes of force as the user becomes fatigued and the formerly appropriate weight becomes excessive.
Whether it’s too little or too much, a mismatch between the level of resistance being applied to the muscles and the momentary strength of those muscles results in either an inefficient or dangerous exercise scenario, and often both within the same set!
Baby Steps: The Variable Resistance Solution
If only there were some way to more closely match the chosen resistance to the momentary strength capacity of the target muscles…wait a minute, we can do that!
Smarter people than I have devised brilliant ways of doing this. They all center around the basic premise that our strength capacity changes moment-by-moment as our joint angles change and we move into and out of mechanical advantage.
That is, we’re stronger at the top of a bench press with straight arms than we are at the bottom with the bar at our chest. We’re stronger at the top of a barbell squat than we are at the bottom.
We’re stronger in the middle of a bicep curl than we are at either end of the range, we’re stronger in the mid-range of a compound row than we are at either end of the range, we’re stronger at the top of a shoulder press than we are at the bottom…you get the idea.
So we’re underloaded in the strong ranges and we’re overloaded in the weak ranges. Got it?
Variable Resistance to the rescue!
How Pneumatic Resistance Works
Pneumatic resistance can be defined as resistance provided by pressurized air.
In resistance exercise applications, this is usually configured in a way that provides resistance to the user’s concentric muscle contraction.
Pneumatic resistance is variable. It provides less resistance when the user is not pushing so hard, and provides more resistance as the user produces more force.
The level of resistance is pre-set, with some specific amount of air in the pressure chamber.
More air in the chamber = greater pressure = greater resistance.
Less air in the chamber = less pressure = less resistance.
Why Pneumatic Resistance Works
Pneumatic resistance gives you greater levels of mechanical tension to more closely accommodate your weak and strong joint angles as you travel through the concentric phase of contraction, whereas a weight does not change at all to accommodate your positions of mechanical advantage or disadvantage.
It also eliminates the momentum that can sometimes develop during explosive lifting. The high forces necessary to produce excess momentum are beneficial because of the higher force demand on the muscles, but the momentum makes this inherently unsafe since it incurs huge impact forces as the weight is rapidly accelerated and decelerated.
By applying smooth compressed-air resistance, pneumatic machines eliminate this dangerous variable.
Why Pneumatic Resistance Can’t Match ARX
The primary area of improvement for pneumatic forms of resistance is the fact that for all the innovation and thinking that goes into them, the mismatch problem is still not fully addressed.
The three main ways our strength changes during exercise—and what our resistance exercise tools must accommodate for maximum effectiveness/efficiency—are:
- From the weak joint angles to the strong joint angles
- From the concentric contractions to the eccentric contractions
- From the start of a set to the end of a set
Let’s take a look at how well pneumatics accommodate these variables:
- Weak to Strong Ranges— C+ Pneumatics give more resistance as the user moves into stronger ranges of motion (the bottom to the top of a chest press, for example), but the resistance that’s provided does not match the user’s potential strength. The user is not exerting at maximum, merely producing the force necessary to move the lever arm against the preselected air-pressure resistance. So there is still an inefficiency since the user is underloaded.
- Concentric to Eccentric— F Unfortunately, pneumatic forms of resistance do not provide anywhere near the resistance necessary to match a user’s eccentric strength capacity. There’s pressure to push against in the concentric, but no “back-pressure” during the ensuing eccentric beyond the weight of the lever arm itself. This represents drastic under-loading (just like weights), and thus a serious inefficiency.
- Start to Finish— D- This one’s not an F because the resistance is reduced a bit as you fatigue and push with less and less force. But the level of pressure in the pressure chamber remains the same from the start to the finish of a set, so you encounter the same pattern of variable resistance the whole time. This means you must set the pressure far below what you could have handled for one or two reps, otherwise your set could only last one or two reps. Under-loading = inefficiency.
See me after class, pneumatics!
Adaptive Resistance Wins Again
ARX technology accounts for all users’ strength changes during exercise perfectly and automatically, every time no matter what, for every person regardless of age, limb lengths, training status, or any other variable.
Every joint angle you move through is perfectly loaded. As you move into and out of mechanical advantage, you are loaded in perfect proportion to your momentary strength capacity.
From the eccentric to the concentric, there is never a mismatch. There is never a point at which you could be producing more force but are not allowed to because the resistance is under-loading you.
From the beginning of the set to the end of a set, you receive a level of resistance that is perfectly matched to your strength capacity. As much as your fresh muscles can handle at the beginning, you can have. As little as you require as you fatigue at the end of the set, our adaptive resistance will accommodate you and provide the precise, correct magnitude of resistance.
Any time your strength changes during a set, for any reason, ARX matches you perfectly. This means you can never be under-loaded (efficiency) and you can never be overloaded (safety). You are always perfectly loaded by a perfect form of pure resistance.
We have solved the mismatch problem inherent in every other resistance exercise tool. This means better results, more safely, and more quickly.
Pneumatic Resistance: Close, But No Cigar
Famed English statesman Winston Churchill is quoted as saying,
“I am a man of simple tastes, easily satisfied with ‘the best.’”
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