Why is Understanding the Resistance of Pilates Reformer Springs Important?

During exercises on a Pilates Reformer, the springs play a key role in setting the resistance and intensity of each movement. At first glance, they may look similar - colorful, metallic, with hooks - but each manufacturer uses different technical standards. This means the same color does not imply the same resistance!

This table and accompanying explanation will help you:

• understand which springs are suitable for which type of exercise,
• compare springs across brands like Align-Pilates, Balanced Body, Elina, and Merrithew,
• and choose or recommend the most suitable set of springs tailored to their abilities and goals for clients.

Align-Pilates

The springs from this brand are color-coded (yellow, blue, red, green) and are designed for a smooth increase in resistance depending on the degree of stretch. Their advantage is a fairly wide range of resistance in specific kg, which is particularly useful for home users or studios that want transparency.

• Resistance range: from 1 kg (very light) to 30 kg (strong)

Merrithew

Merrithew approaches spring resistance in a standardized way through percentages - 25%, 50%, 100%, 125%. The springs are made of nickel-plated music wire, heat-treated, and tested for consistent resistance. This is especially suitable for studios where stability and consistent resistance are important with each use.

• Spring labeling using percentages (%)
• High durability, a very technical approach

Elina Pilates

Elina Pilates springs are precisely designed and tested with exact resistance at a 30 cm stretch. The advantage is the possibility to precisely compare weight load in kilograms, which is ideal for therapeutic exercises or targeted strength work.

• Measured resistance at a 30 cm stretch
• Color ABS ring for easy identification

Balanced Body

Balanced Body springs are made from carbon nickel-plated steel, calibrated for smooth operation and precise resistance strength. Although they do not specify a firmly defined resistance in kg, in practice, the springs have a wide range of resistance that well corresponds to real training experience.

• Patented design
• Precise manufacturing, long lifespan

Important to Know:

• Same color ≠ same resistance. For example, a red spring may mean medium resistance at Align-Pilates, but strong to extra strong at other brands.
• % resistance is an internal standard. For example, Merrithew uses 100% for red, but Balanced Body considers green for 100% resistance.
• Customers need to know:
  
  

• What the given resistance is used for (mobility, strength, coordination…)
• How to compose their "spring mix" for different types of sessions

• Elina Pilates is the only one indicating the exact resistance in kg at a defined stretch. Practical particularly in rehabilitation or precisely targeted work.
• Align-Pilates follows a simple model - color = range in kg. Suitable for easy selection and orientation.

lbs/in or N/mm: These units indicate how much force (e.g., in pounds) is needed to compress or stretch the spring by 1 inch (2.54 cm).

• For example, 0.625 lbs/in = you need 0.625 pounds of resistance for every inch of stretch.
• These values are key for accuracy but less practical for the average user.

Comparative Table of Spring Resistance by Color and Manufacturer

📊 Resistance Springs Comparison Table Between Brands (Equivalents)