Pilates Reformer: Does It Work? A Physiological Breakdown

Pilates has long been associated with flexibility, core strength, and controlled movement, but is it an effective way to build muscle, develop strength, or enhance athletic performance?

One of the most popular forms of Pilates training involves the Reformer, a piece of equipment that uses springs, pulleys, and a sliding carriage to provide resistance. Many people swear by it for core stability, muscle endurance, and injury prevention, but does it hold up physiologically? And more importantly—is it optimal for strength and performance?

Let’s break it down.

What Is the Pilates Reformer?

The Reformer is a versatile piece of equipment designed to challenge muscle endurance and movement control using adjustable spring resistance instead of traditional weights. The moving carriage adds an element of instability, forcing constant engagement of the core and stabilizing muscles.

Unlike weightlifting, where resistance comes from gravity and external loads, Pilates Reformer training emphasizes time under tension (TUT) and controlled movement, often with long eccentric phases and isometric holds. This creates a high neuromuscular demand but lacks the high mechanical tension required for maximal strength gains.

Physiological Adaptations: What Happens to Your Body?

1. Time Under Tension & Muscle Activation

Reformer workouts emphasize slow, controlled reps, increasing the time a muscle spends under load. Longer TUT can contribute to hypertrophy (muscle growth) through metabolic stress and motor unit recruitment—but only to a certain extent.

• Unlike heavy weight training, which stimulates high-force adaptations, the Reformer focuses on low-to-moderate resistance for prolonged periods, favoring muscular endurance over maximal strength development.

• Isometric contractions (where the muscle holds tension without changing length) are common, improving stability but limiting force production.

2. Core Engagement & Stability

One of the major selling points of Pilates is core strength—and for good reason.

• The moving carriage challenges deep stabilizers such as the transverse abdominis, obliques, and spinal muscles, forcing the body to maintain posture against shifting resistance.

• This mimics reflexive core stability, where the body learns to react dynamically to external forces, improving coordination and postural endurance.

• While this is beneficial for injury prevention and functional movement, it does not replace heavy compound lifts like squats and deadlifts for true core strength development.

3. Tendon & Connective Tissue Adaptation

Reformer work applies low-load, high-repetition stress on fascia, tendons, and ligaments, making it an excellent tool for improving tendon resilience and mobility.

• Unlike traditional strength training, which creates high-force adaptations in tendons, Pilates Reformer likely enhances collagen synthesis at lower intensities, making it a useful tool for joint health and injury rehab.

• The elastic strain from spring resistance encourages tensile strength, helping with injury prevention but not necessarily maximal performance.

4. Strength vs. Endurance

• The Reformer does not generate the high mechanical tension needed for maximal strength development.

• The primary adaptation is muscular endurance—slow-twitch fibers (Type I) are activated more than fast-twitch (Type II), limiting explosive power and raw strength gains.

• This makes it great for toning and conditioning but ineffective for athletes needing peak force output.

5. Mobility & End-Range Strength

Pilates often works in lengthened muscle positions, helping with joint mobility, eccentric control, and movement efficiency.

• Many Reformer exercises emphasize end-range strength, improving active flexibility and stability in stretched positions.

• This is valuable for preventing injuries and improving functional movement, but again, it does not build absolute strength or explosive power.

Does It Work? Is It Optimal?

For Strength Development

❌ Not optimal for maximal strength—lacks heavy mechanical tension and progressive overload.

✅ Effective for postural endurance, stabilizer activation, and movement efficiency.

For Hypertrophy (Muscle Growth)

❌ Limited hypertrophy effects—not enough external load to create significant muscle growth.

✅ Can contribute to some muscle tone through long TUT and metabolic stress.

For Joint Health & Rehabilitation

✅ Excellent for rehab, low-impact movement, and joint control.

✅ Beneficial for older populations, post-injury athletes, and those needing movement refinement.

For Athletic Performance & Power Output

❌ Not effective for developing explosive power or maximal force production—lacks ballistic loading and speed work.

✅ Can improve movement quality, coordination, and prehabilitation but should not replace strength training.

Final Verdict: Where Does It Fit?

Pilates Reformer is a fantastic tool for mobility, endurance, core control, and injury prevention—but it’s not a replacement for heavy strength training.

If your goal is to build absolute strength, muscle mass, or athletic explosiveness, the Reformer is not the optimal training tool. However, if you’re looking to improve movement quality, joint health, and functional endurance, it can be a valuable supplement to a well-rounded strength and conditioning program.

The best approach? Use Reformer Pilates as a complementary tool, not your primary method of strength training. Pair it with compound lifts, progressive overload, and explosive movements for a complete training program.

Would you use Pilates Reformer in your routine? Let me know your thoughts!