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Functional Range Conditioning: Stretching Made Smarter

Written By Jayme Pantekoek | Published Feb 13 2022


As athletes, we grow up learning that stretching is important for our health and performance. But information about stretching is often mixed. It seems that in some cases, stretching is good, and in some cases, it can be bad.

In this post, we’ll discuss the two types of stretching that exist, and break down a method of stretching that will better help athletes optimize joint and muscle health—and ultimately their performance.

Passive Range of Motion vs. Active Range of Motion

Static stretches are those in which you stand, sit, or lie down and hold a single position for a period of time. Studies have been out there for years about the decrease in explosiveness after a static stretch is performed. This largely has to do with the deregulation of the nervous system on the muscle spindles, Golgi tendons becoming less active, and tendon creep. This static stretching is also called passive range of motion.

The researchers say a better alternative is to do an active stretch. In an active stretch, you are moving into full ranges of motion using muscle tension. Any time a muscle is actively pushing or pulling into a range of motion, the muscle spindles and Golgi tendon are engaged, this is an active range of motion—or usable range that you can control.

With these two strategies in mind, what should an athlete do to increase their flexibility without losing explosiveness?

Functional Range Conditioning (FRC)

Functional Range Conditioning (FRC) breaks down four components of movement, much like how you would break down the components of strength training. These components of movement are required to optimize muscle and joint movement.

With a typical stretch, mostly the muscle is affected. With FRC, muscles and joints are being affected. The benefit of creating more range of motion in the joints is that the joint can function how it is supposed to function. Otherwise, joints tend to rely on a different joint to pick up the slack and can easily become overused.

Hip mobility is an important example. When losing range of motion in your hips, your lower back will act on behalf of your limited hip movement, creating an overworked back. Over time, your back will become sorer, and the compensation could worsen to chronic back pain or nerve impingements.

So, let’s take a look at the four Functional Range Conditioning components, and why they’re the best ways for athletes to stretch.

Controlled Articular Rotations (CARs)

The first component of Functional Range Conditioning is Controlled Articular Rotations (CARs).

Simply put, you are using your muscles to take a joint to its fullest range of motion actively and under your control. Your nervous system is in control of the movement at all times to create force.

Force is how muscles communicate—if you want change in any tissue, you use force. Force helps muscles push through the boundaries of the range of motion in that joint. This is often done by moving it in a full circle (hence “rotations”) under control. To assist with this force and circular movement, we use weights, massage, stretching, sprinting, etc.

As the muscles warm up, you get more communication to the muscle. The joint circle should eventually become bigger and bigger as you use more force to push through those boundaries. This is active range of motion at its best—communicating to your muscles that it is okay to go into that range of motion because you have control and you won’t get hurt in that range.

If we were to use a passive range of motion instead of these rotations, we would not have the same control over that range of motion or the ability to produce force. In turn, the muscle is at risk of injury because the muscle will be trying to stabilize the joint.

Progressive and Regressive Angular Isometric Loading (PAILs/RAILs).

The second component of Functional Range Conditioning is Progressive and Regressive Angular Isometric Loading (PAILs/RAILs).

This is where we communicate to a joint and muscle that it can produce high amounts of force or stabilization at our new controlled range of motion at the end ranges of the joints—progressive angles and regressive angles. You do this by putting your body into a stretched position where you push into an immovable object to create a high level of force.

For example, if you were to do a hurdle stretch and go into your “stretched” position, the hip and hamstring are being affected. If you push into the ground, you’re creating a high level of force which tells the muscles (and more importantly your nervous system) that you can and are capable of creating high levels of force at that range.

Your body and brain read this as stabilization, and they will now accept that new range. In turn, this makes you have more “flexibility.”

In this example of the hurdler stretch, the hamstring in that position is an example of the progressive angle in the hip because the angle is getting greater the further the hamstring and hips motion.

An example of the regressive angle is the hip flexor, quad, and psoas. In the same hurdle stretch position, the angle is lessening or regressive for those muscles.

This is of huge value to athletes because we never use just one side of the body or joint. All of it has to be trained, and by doing PAILs and RAILs, we affect both sides at the same time—creating harmonious communication to the joint

If we don’t bring our regressive angles to their end range of motion, we can lose force just like we can in the full extension of the muscle.

Most people don’t consider this. If you can’t control or create force in the end range of the contracted position or regressive angle, there is just as much risk of getting hurt as there is with muscle extension.

This makes PAILs and RAILs critical.


The third component of Functional Range Conditioning is hovering through the range of motion. The difference between CARs and Hovering is the angle that your body is using to take advantage of gravity.

If you raise your arms straight above your head, your shoulder goes through a good range of motion. At the top of the movement, however, the tension the muscle feels is pretty low.

Now, if you go into that same position with your arm extended straight overhead, but this time you’re lying face down when you do it, gravity affects that shoulder joint and muscle much more.

With our arms hovering over the ground in this way and needing to fight gravity more intensely at that angle, we’re simulating an external load through this range of motion. To take this a step further, we could add weight to these chosen angles.

The difference between hovering and PAILs and RAILs is that the hovering smooths the control through the full range of motion. PAILs and RAILs focus on unlocking new ranges of motion. Both are important for the health of our muscles and joints.


The last component of Functional Range Conditioning is solidifying the new range of motion so that it does not revert to its old position. Once we’ve unlocked a new range of motion through the other components of FRC, we want to be able to continue to control and produce force within that new range.

To do this, or to solidify this range of motion, we add load—whether it’s bodyweight, angles to utilize gravity, or actual weight. Once we add load, we move slowly in an eccentric pattern. An eccentric pattern is the lowering or lengthening phase of a movement. An example of this would be the down phase of a squat or the sinking phase of a step when walking.

This is the strongest phase of movement because we use this phase to decelerate our bodies or an object. It has to be the strongest pattern because our bodies will not let us accelerate more than we can decelerate—it’s how we stay injury-free.

The same goes for the end ranges of our movements in our joints, muscles, and tendons. If we cannot decelerate through that range, we will not own that range.

So, we add load and eccentric patterns to solidify this range—own this range.



There are many ways to stretch. I’m sure you’ve tried most of them.

But, out of all of the ways to accomplish stretching, (passive, active, PNF, yoga, etc.) FRC is the most dynamic system.

Because it helps athletes add more mobility and further their range of motion, it accomplishes everything an athlete can benefit from when it comes to muscle, tendon, ligament, and joint capsule health.

FAST Athletics builds FRC components into all of our programming, helping to build mobility and resiliency among our athletes. If you’d like a tailored training program that also considers smart stretching and mobility, reach out to us today.

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