A Reformer is a specialized Pilates machine with a sliding carriage, adjustable springs, ropes, and pulleys that lets you perform exercises against variable resistance. Unlike mat Pilates, which relies on body weight alone, the Reformer adds resistance through its spring system while guiding your movement along a fixed track. It’s the most recognizable piece of Pilates equipment and the centerpiece of most studio classes.
How the Machine Works
The Reformer looks like a narrow bed frame with a flat platform (the carriage) that slides back and forth on rails. You lie, sit, kneel, or stand on the carriage and push or pull against resistance created by a set of springs attached to one end. Ropes connected to pulleys let you work your arms and legs through a wide range of motion while the carriage moves beneath you.
The springs are color-coded by resistance level. On most machines, a yellow spring provides the lightest tension (roughly 1 to 7 kg across its range of extension), blue is light (3 to 15 kg), red is medium (4 to 20 kg), and green is the heaviest (5 to 30 kg). You can attach multiple springs at once, so the total resistance is highly customizable. Importantly, the resistance isn’t static: it increases the further you extend the spring, which means the exercise gets harder at the end of each movement rather than staying constant throughout.
Shoulder blocks at one end of the carriage keep you from sliding off, and a foot bar at the other end gives you something to push against. Instructors adjust the spring combination, foot bar position, and rope length to tailor each exercise to your body and fitness level.
Classical vs. Contemporary Reformers
Not all Reformers feel the same. Classical models, like those made by Gratz (the original manufacturer), use hard rubber wheels rolling inside U-shaped metal tracks. This deliberately creates friction, so the carriage doesn’t glide back on its own. You have to engage your deep core muscles to control the return, which is part of the training. Classical machines also have 10 wheels, including an extra pair at the rear that guide the leather straps.
Contemporary Reformers from brands like Balanced Body and Merrithew use high-precision ball bearings, polyurethane wheels, and smooth aluminum tracks. The result is a quieter, more fluid glide. These machines typically run on 8 wheels and rely on widened tracks and optimized bearings for stability. Both styles are effective. Classical machines prioritize core challenge through resistance in the carriage itself, while contemporary models offer a smoother ride and often feel more approachable for beginners.
What Reformer Pilates Does to Your Body
The core muscles that wrap around your torso and stabilize your spine are the primary target. Research published in PMC confirms that Pilates exercises strengthen these muscles and increase spinal flexibility, with the Reformer’s unstable sliding platform forcing your stabilizing muscles to work constantly, even during simple movements. The back muscles along your spine play a particularly important role in maintaining stability on the moving carriage during extension exercises.
Beyond core strength, a 2025 study found that Reformer Pilates leads to greater improvements in agility, explosive power, and precise coordination compared to mat-based work. A separate study involving people with multiple sclerosis found that Reformer Pilates produced larger gains in muscle strength and flexibility than mat Pilates alone. The adjustable springs and guided motion of the machine provide both resistance and support simultaneously, which is a combination that’s hard to replicate with body weight exercises.
Because the spring resistance keeps muscle activity at moderate levels (often around 30% of maximum voluntary contraction for basic exercises), Reformer work is also used in rehabilitation. Clinical experts now recommend it as a therapeutic method for low back pain and scoliosis. Multiple trials have shown statistically significant reductions in the frequency, intensity, and duration of chronic low back pain after Pilates-based programs. Studies have also linked regular practice to improved self-efficacy, mood, and sleep quality in college-age participants.
Reformer vs. Mat Pilates
Mat Pilates uses your body weight on a floor mat to build core strength, flexibility, and muscular endurance. It’s excellent for balance, coordination, and control of everyday movements. The Reformer adds a dimension that mat work can’t easily provide: external resistance that you can dial up or down, plus a moving surface that challenges stability in ways a static floor doesn’t.
If your goals involve building more power, working through a larger range of motion, or rehabilitating an injury with controlled support, the Reformer has a clear edge. If you want something portable, affordable, and effective for general fitness, mat Pilates delivers. Many people do both, using mat classes for convenience and Reformer sessions for targeted strength work.
What to Expect in a Class
Most Reformer classes run 45 to 55 minutes and cycle through exercises for the legs, core, arms, and back. You’ll spend time lying on your back pushing the carriage with your feet, sitting or kneeling while pulling the ropes, and standing on the carriage or the platform for balance challenges. A good instructor will set your springs before each exercise and cue your breathing, alignment, and movement speed.
Classes range from gentle rehabilitation-focused sessions to high-intensity formats sometimes labeled “dynamic Pilates” or “HIIT Pilates.” Group classes typically accommodate 8 to 15 people, each on their own machine. Private sessions cost more but allow the instructor to customize every detail to your body.
How Often and How Quickly You’ll See Results
Two to three sessions per week is the most commonly recommended starting point if Pilates is your primary form of exercise. If you’re adding it alongside an existing workout routine, once a week is enough to start building familiarity. As you progress, you can add a second or third weekly session or incorporate Reformer-inspired movements into your gym routine at home.
Joseph Pilates is credited with saying: “In 10 sessions you’ll feel the difference, in 20 sessions you’ll see the difference, and in 30 sessions you’ll have a whole new body.” Modern instructors largely agree with that timeline. Improvements in body awareness, posture, and how your muscles engage can show up within the first one to two weeks. Visible changes in muscle tone and flexibility typically follow after several weeks of consistent practice.
Who It’s Best Suited For
People of all ages and fitness levels use Reformer Pilates. The spring system makes it uniquely scalable: lighter springs for rehabilitation or beginners, heavier springs for athletes looking to build strength and power. It’s particularly well suited for anyone dealing with chronic low back pain, recovering from injury, or looking to improve posture and spinal health.
That said, the original Pilates method places high neuromuscular demands on the entire body. If you’re recovering from a significant injury or managing a complex condition, working with an instructor who has proper training in rehabilitation is important. The quality of instruction matters more on the Reformer than in most group fitness settings, because spring selection and form corrections directly affect whether the exercise helps or strains your body.