Understanding Gratz Springs: Resistance & Support
Reviewed by: Tim Kuehnlenz, Head of Engineering; Adam Leenig, Development Director
At Gratz, we know you want to understand the springs that power your Pilates practice. We're committed to helping you develop that knowledge. Springs are more than just resistance—they're tools for support, guidance, and control.
Understanding Gratz Spring Design
A Pilates spring tension is determined by four core design factors:
- Spring length (free length, uncompressed)
- Number of coils
- Coil diameter (the width of the spring itself)
- Wire diameter (the thickness of the material the coil is made from)
Longer springs with more coils, a wider coil diameter, and thinner wire stretch more easily and produce lower resistance. Shorter springs with fewer coils, a narrower coil diameter, and thicker wire resist stretching more and produce greater resistance.
Using the four core design elements, Gratz offers springs with different tensions. Each spring is designed with a specific combination of these variables to create the resistance and behavior appropriate for its intended apparatus and exercises. To bring this to life, we’ll compare three similar but very different springs.
Spring Design Comparison
Look closely and carefully at each spring above.
Observe how the Standard Reformer spring (top) uses tight, numerous coils for its resistance profile.
Now look at the next spring, the Vintage Long Neck (middle) it is quite different actually, and not just the “long-neck”. This spring is about the same length in total, but fewer coil number, coils covering a shorter distance across the entire spring length. Also, the coils are slightly tighter. While visually these don’t look very different, the resulting tension is significantly different.
Finally, look at the Wunda Chair spring (bottom). The coils here have a larger diameter than either of the other two, and this thickness, combined with the way the coils are shaped, makes it fundamentally different from the Reformer and Vintage Long Neck. As you'll see in the chart below, the Wunda Chair spring is the strongest spring we offer at Gratz.
Five Key Factors That Impact how Springs Feel
This comprehensive guide below explores five key factors that affect how springs respond during your work, giving you the knowledge to use them thoughtfully and adjust them confidently for yourself and your clients.
There are five key factors that directly affect how the springs respond to each exercise:
- Spring force during extension
- Number of springs
- Body proportion
- Body positioning
- Springs wear
Force Is Generated When Springs Are Extended
Below is the Gratz Spring Force vs. Extension chart which shows the spring force (in pounds) vs. extension (in inches).
Note: The chart shows approximate spring force at each measured extension. The 12-inch range shown is the testing range, not necessarily the full extension capacity of every spring. Some small variation between springs is normal. Over the years, Gratz has refined its manufacturing process, and today's springs are more consistent from one to the next than earlier production, so older springs may show slightly more variation in tension.
As shown in the chart above, spring force increases as the springs are stretched. Unlike working with a fixed weight, spring resistance changes throughout the range of movement and must be managed during both extension and return.
For example, one Reformer spring extended 12 inches produces approximately 20 pounds of force. During Footwork with four springs extended 12 inches, the practitioner manages approximately 80 pounds of total spring force pulling the carriage toward the Foot Bar.
Extending the springs farther increases that force, up to the maximum carriage travel available on each Reformer size: 22 inches on an 80" Reformer, 28 inches on an 86" Reformer, and 32 inches on an 89" Reformer.
Pilatesology Exercise Example: Footwork with 4 Standard Reformer Springs
Footwork clearly demonstrates how spring force changes throughout movement. As the carriage moves away from the Foot Bar, the springs extend and resistance progressively increases. As the carriage returns, the practitioner must control the springs as they recoil and guide the carriage home, even as the amount of force decreases. The work continues in both directions—not only during the outward press.
Movement speed does not change the amount of force a spring produces at a given extension. That force is determined by how far the spring is stretched and by the spring’s design.
Speed can, however, affect how the resistance is experienced by the body. Moving quickly through the range may feel different or become more momentum-driven than moving slowly and deliberately through the same range, even though the spring produces the same force at the same point of extension.
How Spring Force Changes Its Role During an Exercise
Although spring force follows the same basic principle, greater extension produces greater force; that force does not always play the same role in movement.
Depending on the exercise and where the springs are attached, spring force may create resistance, provide support, assist a phase of movement, or guide the body and apparatus.
The following exercises demonstrate how the role of springs can change.
Pilatesology Exercise Example: Electric Chair Press Up Front with 2 Springs Top
As you press downward, the springs extend and create increasing resistance. The practitioner works against that resistance while the springs simultaneously provide a line of support and guidance for the body.
On the return, the relationship changes. As the springs recoil, their force assists the practitioner in returning from the extended position.
The same springs therefore play different roles throughout different phases of one exercise.
Pilatesology Exercise Example: Wunda Chair Pull Up with 1 Top, 1 Bottom Spring
Pull Up creates a different relationship between the body and the springs.
The springs are attached from two different directions, allowing them to provide resistance and support through different phases of the movement.
The top spring contributes force as the practitioner lifts, while the bottom spring plays an important role in supporting and controlling the return.
This illustrates why spring setup is not simply about creating more or less resistance. Where the springs are attached determines the direction of their force and how that force functions throughout the exercise.
Gratz Ambassador Miguel Silva expands on this relationship between spring setup, support, and challenge on the Wunda Chair: “After several years of exploring, closely studying videos of Joseph Pilates' students and clients, applying those observations and practicing on my own body, I have come to the conclusion that this wonderful chair is a true gym at home, where we can work every part of the body. The challenge created by the combined action of springs, pedal, body, gravity and movement takes us towards physical and mental well-being, with results that come quickly and are clearly visible.
That said, for me there is no single spring setting for each exercise. I truly encourage you to explore, so that you can feel whether you are receiving more support or more challenge—but never so little that you are ‘fighting’ the springs, and never so much that you receive no work at all.
Let me give you an example: try the Push Down with two springs on the middle setting instead of one. You will certainly feel the meaning of the exercise's name.”
How Attachment Point Changes Spring Extension
Where a spring is attached also affects how far it must extend during an exercise.
The Rolldown Bar on the Studio Wall Unit or Cadillac provides a clear example.
A higher bar position generally creates greater spring extension. A lower position creates less extension. Because spring force increases with extension, changing the attachment point changes your relationship to the springs. This is also why teachers may adjust the hook based on each client this based on each client.
At 12 inches of extension, one Roll Down spring produces approximately 11 pounds of force. With two springs, that force doubles to roughly 22 pounds. Spring count, attachment point, and extension therefore work together to determine the resistance and support experienced during the movement.
For a shorter client, adding a double hook lengthens the connection and brings the bar closer to their reach. This allows the client to begin with a more appropriate amount of spring extension rather than with the springs already stretched farther than intended.
During a Roll Down, the bar should be positioned so the springs provide suitable resistance and support as the practitioner lifts and articulates. If the bar is too high, the springs may begin with greater extension and therefore greater force. If it is too low, they may not provide the intended support. The goal is for the springs to assist the movement without overpowering it.
Pilatesology Exercise Example: Bicep Curl
The Bicep Curl demonstrates how dramatically changing attachment height can change the work. With the Rolldown Bar positioned at the bottom eye hooks, the direction and amount of spring extension change. You experience a stronger pulling relationship against the springs, making the movement and control of the bar feel very different.
Number of Springs Changes the Amount of Resistance
Changing the number of springs directly changes the total spring force acting on the body and apparatus.This is why spring count alone cannot define how difficult an exercise will be.
What matters is what the springs are doing within the exercise and what the body must produce in response.
Pilatesology Exercise Example: Reformer Long Stretch with 1 or 2 Springs
Long Stretch typically uses two springs.
At 12 inches of extension, two standard Reformer springs produce approximately 40 pounds of total spring force.
As you return from extension, those two springs recoil and help guide the carriage toward home.
Now consider the same exercise with only one spring.
At the same 12 inches of extension, the total spring force is reduced from approximately 40 pounds to 20 pounds. With less spring force pulling the carriage toward home, you receive less assistance on the return.
Your power house must now contribute more actively to pull the carriage in while maintaining control and organization throughout the movement.
The example demonstrates an important principle: reducing spring resistance can sometimes make an exercise more demanding because the body must supply more of the control that the springs were providing.
Body Proportion (Height, Limb Length, Weight)
The spring setting may be the same, but every body interacts with it differently.
Height, limb length, and overall body proportions affect how far a spring extends during an exercise. Because greater extension creates greater spring force, two practitioners performing the same exercise with the same spring setting may experience a different relationship to the springs.
Differences in proportion can change:
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The distance traveled
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The amount of spring extension created
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The force produced
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How that force must be managed throughout the movement
Height and Reformer Footwork
Consider two practitioners performing Footwork with the same spring setting. A taller practitioner with longer legs may move the carriage farther than a shorter practitioner performing the same exercise. Because the carriage travels a greater distance, the springs extend farther and produce more force.
The taller practitioner must manage that increasing force through a longer range of motion, both as the carriage moves out and as it returns. The springs and spring setting are exactly the same, but the amount of spring extension and therefore the force experienced during the exercise can differ based on the practitioner’s body proportions.
Body Proportions and Arm Spring Placement on the Studio Wall Unit
Body proportions can also influence where springs are attached. On the Studio Wall Unit, the attachment point should create an appropriate relationship between your reach, range of motion, and the amount of spring extension required by the exercise.
A shorter practitioner may need the Arm Springs attached to a lower hook, while a taller practitioner with longer arms may require a different attachment point. If a practitioner’s reach causes the springs to extend farther than intended, the resulting increase in force can change how the exercise is experienced and performed.
The goal is not simply to make an exercise harder or easier. It is to position the springs in relation to the individual body, so they provide the intended resistance and support throughout the movement.
Relationship of Height and Placement of Arm Springs on the Studio Wall Unit
Watch this in practice: as you compare clients of different heights on the Studio Wall Unit, notice how each has their Arm Springs attached to a different hook. The taller client's springs stretch farther across the same range of motion, while the shorter client's springs stay attached lower to maintain an appropriate amount of extension. This is proportion and placement working together in real time.
Body Positioning Affects Spring Tension on the Body
Body proportions influence how an individual naturally interacts with the apparatus. Body positioning adds another variable: where the body is placed in relation to the spring.
Even with the same spring setup, changing the body’s starting position can change how far the spring extends, the direction of its pull, and the balance between the support provided by the spring and the control required from the body.
How Leg Springs Guide the Hips on the Cadillac
Leg Springs demonstrate how body position can change the role of the spring within an exercise.
As the hips lift away from the Cadillac bed, the relationship between the body and the springs changes. If the spring tension provides too much assistance, the springs may begin to lift or hold the body rather than requiring the practitioner to actively maintain the position.
With appropriate tension, the springs provide a line of support that helps guide the hips into elevation while the body remains actively engaged. Leg Circles demonstrate this relationship particularly well: as the legs move through the circles, the springs help support the elevated position while the practitioner maintains the lift, organizes the body, and controls the movement.
The springs are supporting the movement without taking it over. They provide guidance and assistance while the practitioner remains responsible for stability, control, and precision.
This relationship between spring support and active control is also central to how Gratz Ambassador Risa Mathews describes the Cadillac, Guillotine, and Tower springs: “The Gratz Cadillac/Guillotine/Tower springs are very reliable springs because of their consistency in function to support the exercises Joe Pilates designed for us. Many of the exercises utilizing these springs demand a specific weight, length, and range capacity in order for the exercise to be executed efficiently. From supporting body weight, to responding to breath, when you train with Gratz springs you will experience the method as it was meant to be practiced. Safe spring response, reliable, unchanging tension, quality and longevity of use. This is why we love the Gratz Cadillac springs, and they are used 10 hours a day without fail!” -Risa Mathews, Boditree Pilates & HealiingCadillac: Body Positioning And Its Impact On Mermaid
Where the body is positioned in relation to the spring also influences how much the spring extends and how its force is experienced throughout an exercise.
Mermaid provides a clear example. Performing the exercise kneeling versus sitting places the body at a different starting point in relation to the spring. As a result, the spring moves through a different range of extension, changing the amount of force produced and how that force interacts with the body.
Throughout the movement, the role of the spring can also shift. At certain points, it may provide support or assistance; at others, the increasing force of the spring may require the practitioner to contribute more control.
The spring itself has not changed. By changing the body’s position in relation to it, however, the amount of extension and the role the spring plays within the exercise can change.
Body Position And Its Impact On Small Arm Chair Exercises
On the Small Arm Chair, body position is a key variable in how the spring responds. In 2nd position exercises, knee placement directly affects the amount of spring extension. Knees positioned slightly forward keep extension moderate, producing manageable resistance. As the knees move further back, the spring extends more, increasing resistance throughout the full range of the movement.
Body position also affects chair stability. As the knees move further back, the base of support narrows, requiring you to stabilize the chair in addition to managing spring resistance. This combination of resistance and stabilization is why Small Arm Chair work demands a high degree of precision and engagement.
Spring Wear Diminishes Spring Tension
Gratz springs are designed for a long service life when used within their intended range of motion.
The main cause of accelerated wear is repeatedly stretching a spring beyond that range, which can cause the coils to take a permanent set — the spring no longer returns fully to its original length, and it loses a small amount of its original force each time this happens. A small, even amount of set during a spring's early life is normal; more noticeable or uneven set is usually a sign the spring has been overextended. How far past the intended range matters more than how fast the movement is, though sudden or jerky loading can add extra stress and should be avoided.
Allowing a spring to snap back and recoil on its own, rather than guiding it back with control, can damage the spring and shorten its lifespan. Always control the return rather than letting it release freely.
Body proportions can influence how far springs extend during certain exercises, but height alone does not determine spring wear. Apparatus setup, range of movement, frequency of use, and the amount of spring extension can all affect how springs perform over time. Appropriate setup and regular inspection help keep springs working within their intended range.
Over time, this gradual change means an older spring and a newer spring can produce different levels of resistance at the same amount of extension, even under identical conditions. That difference affects how the apparatus feels and how much resistance or support the spring provides during an exercise. Understanding spring wear helps explain why familiar spring settings may feel different over time, even when the exercise, apparatus, and number of springs remain the same.
It is important to inspect your springs regularly
Make spring inspection part of your weekly routine. Check for uneven set in, changes in coil shape or spacing, or unusual noise during use, which may indicate that a spring has been overstretched. Some set in is a normal part of spring wear over time and typically occurs evenly across the coils.
For those who want to maintain a consistent, like-new spring feel, Gratz recommends replacing springs approximately every 18 months with regular use or every 24 months with lighter use. These time frames are a guide; spring condition and frequency of use may warrant earlier replacement.
Because taller practitioners and longer-limbed bodies tend to extend springs farther, equipment used primarily by these clients may need more frequent replacement.
Reference Gratz cleaning instructions to keep springs free of buildup that can accelerate wear.
Footwork with 4 Springs—When Springs Wear
New springs at full extension deliver roughly 80 pounds of total resistance. Over time, as springs age through use, they naturally lose some of their force production. A spring that's been in use over time might produce 70 pounds at the same extension. This shift changes how the resistance feels during movement. Your body experiences less resistance than it did when the springs were new.
This is simply the nature of springs; they're built to last, and gradual change over time is normal.
Whether you embrace this gradual wear or replace springs regularly comes down to preference.
Understanding Springs Creates Deeper Understanding of The Work
Across Gratz’s spring-based apparatus, the same fundamental principle applies: spring force increases with extension, while body position and spring placement influence how that force is experienced throughout the work. Whether it's the footwork on a Reformer, the push down on a Wunda Chair, or the precise control of Small Arm springs, the principle is constant. Your understanding of how springs respond to movement—how they assist in some phases and resist others—is what lets you use them effectively and adjust them thoughtfully for each client.
Special Thanks
We thank Gratz Pilates Co-owners John Riccitiello and Elizabeth Osterman, along with Kat Strafford, President of Gratz Pilates, for their leadership and support in bringing this resource together.
We also thank Alisa Wyatt from Pilatesology and Amy Berger from Star Pilates, for their valuable contributions, as well as our Gratz Ambassadors for sharing their experiences and insights throughout.
Questions About Gratz Springs?
What else would you like to know about Gratz springs? Share your questions in the comments below and let us know what you’d like us to explore next.
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Gratz Pilates
October 20, 2026
Thank you, Karen! We’re so happy you enjoyed the article and the Gratz Galleries. We hope Gratz finds its way into your practice as well.