A science-backed perspective from Aspen & Pine Pilates
One of the most common misconceptions about Pilates is that it lacks “real” strength training. That belief usually comes from seeing Pilates only as reformer work—or worse, as light, choreography-based aerobic movement on a reformer
Classical Pilates is something very different. It is a full variable-resistance strength system, using springs across multiple apparatus to load the body in ways that closely align with modern exercise science.
At the center of that conversation is variable resistance training.
What is variable resistance training—and why does it matter?
Variable resistance training refers to resistance that changes throughout the range of motion, rather than remaining constant like a dumbbell.
Examples include:
Resistance bands (tension increases as the band lengthens)
Chains on barbells (more load lifted as leverage improves)
Cable machines (consistent tension with changing joint mechanics)
Pilates springs, used across the Reformer, Cadillac, Chairs, Guillotine, and Ped-O-Pole
Research consistently shows that variable resistance training can produce strength gains comparable to traditional constant resistance training (barbells and dumbbells) when volume and effort are matched. The reason is biomechanical: humans are not equally strong at every joint angle, and variable resistance better matches how force is produced across a movement.
Pilates springs: variable resistance across the entire classical system
Pilates springs do not exist only on the reformer carriage. In the classical system, springs are applied through multiple orientations, lever lengths, and body positions:
Reformer: moving carriage resistance requiring both force production and controlled deceleration.
Cadillac (Trapeze Table): long-lever spring work for arms, legs, and trunk that magnifies torque demands.
Chairs (Wunda, High, Arm Chair): vertical loading that often demands high force output relative to bodyweight.
Guillotine: overhead spring resistance emphasizing axial length, shoulder organization, and spinal control. And work similar to the Cadillac.
Ped-O-Pole: minimal base of support with spring assistance, requiring full-body integration and balance under load.
Across all apparatus, spring tension increases as the spring lengthens, meaning resistance is progressive, not static. This places Pilates squarely within the variable-resistance category supported by current strength training research.
Hug a Tree: a clear example of variable resistance
The classical Pilates exercise Hug a Tree, typically performed with arm springs on the Cadillac or Guillotine, is an excellent example of variable resistance in action.
To understand this clearly, compare it to two common gym exercises:
Hug a Tree (Pilates springs)
Resistance increases as the arms close
The hardest portion of the movement occurs near end range
Trunk, rib cage, and scapular organization must be maintained as load rises
No external bracing or momentum is available
Cable fly
Provides continuous tension through the range of motion
Resistance profile depends on cable height, body angle, and line of pull
Easily adjustable for heavier absolute loads
Still variable in effective difficulty due to changing moment arms
Dumbbell flat fly
Uses constant resistance
Easiest near the top when dumbbells are stacked over the shoulders
Hardest near the bottom due to gravity and shoulder torque
No increase in resistance as the arms close—only a change in leverage
All three train shoulder horizontal adduction and target the pectoralis major. The difference is how resistance behaves.
Hug a Tree most closely mirrors elastic resistance: load rises as the movement progresses, demanding increasing force and control precisely where many people lose alignment. That is variable resistance—by definition.
Where this conversation goes next
Here’s where an important distinction begins.
Training designed to grow muscle (hypertrophy) is not the same as training designed to maximize strength, even though the two overlap. The goals, loading strategies, repetition ranges, and adaptations differ.
In our next blog, we’ll explore:
- the difference between hypertrophy-focused training and strength-focused training,
- why both matter at different stages of life,
- and how the classical Pilates system—across all apparatus—can be programmed intentionally for each goal.
At Aspen & Pine Pilates, we don’t reduce Pilates to a reformer class of 10. We teach it as a complete variable-resistance strength system—grounded in tradition and aligned with modern science. Workouts designed to meet your individual fitness goals.
