The Strength Pilates Builds
The Science of Muscle Contraction
If you’ve ever wondered how Pilates builds strength without the bulky muscles of weight training, the answer lies deep in your body—at the level of your muscle fibers.
Unlike many forms of exercise that emphasize sheer force or volume, Pilates emphasizes control, resistance, and precision. And within that framework, there's a particular kind of muscle contraction that Pilates relies on more than most: eccentric contraction.
Let’s break down what that means, how it works in your body, and why it’s so effective.
What Are Muscle Fibers—And How Do They Work?
Muscle fibers are long, thread-like cells that bundle together to form muscles. Inside these fibers are structures called myofibrils, made up of proteins—actin and myosin—that slide past each other to create movement. This process is often referred to as the sliding filament model of muscle contraction.
These contractions can happen in three distinct ways:
Concentric contraction: the muscle shortens while contracting (like pulling a weight closer to you)
Isometric contraction: the muscle contracts without changing length (like holding a plank for a period of time)
Eccentric contraction: the muscle lengthens while still engaging (like slowly lowering from a push-up)
Most conventional exercises, like lifting weights or sprinting, emphasize concentric contraction—think of muscles bunching up and getting denser. Pilates, on the other hand, is unique in how much it emphasizes eccentric contraction—which lengthens and strengthens muscles with control.
Why Eccentric Contraction Matters in Pilates
Eccentric contractions happen when your muscles resist a force instead of pushing through it—think of slowly lowering your leg against a spring on the Reformer, or controlling your descent from a bridge.
This form of contraction:
Strengthens muscles more efficiently
Lengthens muscle fibers, helping to sculpt rather than bulk
Challenges the nervous system more deeply, since the brain must stay more engaged during eccentric motion
Protects joints through better control and balance
And because eccentric contraction puts muscles under more tension, it can lead to greater strength gains—with far less wear and tear than high-impact or high-volume workouts.
But here’s the key: control is everything. That’s why Pilates emphasizes slow, deliberate movement with attention to breath, form, and alignment.
The Muscle Fibers Pilates Trains Most
While Pilates activates all types of muscle fibers, it especially targets your slow-twitch fibers—the ones built for endurance, stability, and posture.
These fibers respond best to:
Low-intensity, sustained movement
Precise, repetitive activation
Core-focused and stabilizing exercises
That’s why Pilates feels so different from traditional strength workouts—and why it builds strength that supports balance, mobility, and long-term joint health.
Pilates doesn’t just “tone” existing muscles—it deeply conditions essential but underused muscles like the:
Deep core (like the transversus abdominis)
Rotator cuff
Inner thighs
Buttocks and glute medius
Iliopsoas (a deep hip flexor that links your legs to your spine)
Pilates Trains Your Brain, Too
Interestingly, eccentric contraction doesn’t just challenge your muscles—it also demands more neurological engagement. Research shows your brain becomes more active, increases blood flow, and pays closer attention during eccentric movements. That’s one reason Pilates feels so mentally centering: it’s not just a workout—it’s a neuromuscular retraining system.
In Summary: Why This Matters for You
Pilates gives you strength without excess strain, and power without bulk. By focusing on eccentric muscle contraction, Pilates teaches your body to resist, control, and adapt.
This leads to:
Stronger, longer muscles
Better movement control
Improved stamina and joint protection
Greater mind-body awareness
At SOMA, we don’t just train movement—we train intelligent, efficient, and resilient movement. That starts at the muscle fiber level—and it shows up in how you walk, stand, breathe, and live.