Pilates does count as a form of strength training, but with important caveats. It builds functional strength, improves muscle endurance, and can produce measurable gains in force production. However, it works differently than traditional weight training and has real limitations when it comes to building muscle size or maximal strength. Whether it “counts” depends on what you’re trying to achieve.
What Makes Something Strength Training
The core requirement is simple: your muscles need to work against resistance that’s challenging enough to cause them to adapt and get stronger. The American College of Sports Medicine recommends at least one set of 8 to 12 repetitions of resistance exercises targeting the major muscle groups, performed at least two days per week. The CDC’s physical activity guidelines call for muscle-strengthening activities on two or more days a week that work all major muscle groups, including legs, hips, back, abdomen, chest, shoulders, and arms.
Pilates checks most of these boxes. It uses body weight, spring-loaded machines, and resistance bands to challenge muscles through controlled movements. A typical session works your core, legs, back, shoulders, and arms. So by the broad definitions that public health agencies use, Pilates qualifies as muscle-strengthening activity.
The Strength Gains Are Real
Research consistently shows that Pilates produces genuine strength improvements. A pilot study in post-menopausal women found that a Pilates program increased grip strength by about 8%, lower body strength (measured by a chair-stand test) by 23%, and abdominal strength by nearly 31%. Those are meaningful numbers, especially for people starting from a low baseline or returning to exercise after time off.
A large systematic review comparing Pilates to other forms of exercise looked at data from nearly 960 participants. The results showed no significant difference in dynamic or isometric strength outcomes between Pilates and other exercise types. In other words, Pilates held its own against conventional training methods when it came to making muscles stronger.
Where Pilates Falls Short
Strength and muscle size aren’t the same thing. You can get stronger without your muscles getting visibly bigger, and that’s exactly what tends to happen with Pilates. The same post-menopausal study that found impressive strength gains detected no changes in overall body composition or trunk lean mass. The researchers noted this was likely due to the relatively low total training volume and the absence of dietary changes, but it also reflects a fundamental limitation: Pilates rarely provides enough resistance to drive significant muscle growth.
Building noticeable muscle requires progressively heavier loads, typically in the range of 60 to 85% of your one-rep max. Pilates reformer springs produce modest resistance. A full-strength (100%) reformer spring generates roughly 6 to 7.5 pounds of initial tension, increasing by about 1.25 pounds for every inch the carriage travels. Even at full extension, you’re looking at around 21 pounds of resistance from a single spring. Stacking multiple springs increases this, but you’re still working with far less load than a barbell squat or deadlift would provide. For someone already moderately strong, the resistance ceiling becomes a real bottleneck.
Progressive Overload Is Possible but Limited
The principle that drives all strength adaptation is progressive overload: gradually increasing the challenge your muscles face over time. In weight training, this is straightforward. You add more weight to the bar. In Pilates, overload looks different. You might increase repetitions, add longer holds at difficult positions, use heavier springs, incorporate resistance bands, or perform exercises on unstable surfaces. A basic roll-up, for instance, can be progressed with ankle weights, an incline surface, or a band for added upper body resistance.
These strategies work, particularly for beginners and intermediate practitioners. But they have a ceiling. There’s only so much you can do with spring tension and body weight before the loading simply isn’t enough to force further adaptation. Someone who has been doing Pilates consistently for a year or two will eventually plateau on pure strength metrics unless they add external resistance training.
How Often You Need to Practice
Frequency matters more than you might expect. Research suggests that practicing Pilates three times per week for six months leads to measurable improvements in both upper and lower body strength, flexibility, and aerobic endurance. Even once-a-week sessions have been shown to improve muscle mass, core strength, balance, and body awareness. Joseph Pilates himself recommended at least four sessions per week for best results.
If you’re using Pilates as your primary form of strength training, aim for at least two to three sessions per week. One session a week will maintain some baseline fitness, but it’s unlikely to produce the kind of progressive strength gains you’d get from more frequent practice.
Reformer vs. Mat Pilates
Not all Pilates is created equal when it comes to strength training value. Mat Pilates relies entirely on body weight, which means resistance is limited to what gravity and leverage provide. It’s excellent for core endurance and stability, but it won’t challenge your legs or upper body the way loaded exercises do.
Reformer Pilates adds spring resistance, which makes it closer to traditional strength training. With multiple springs at different tension levels (ranging from 25% to 125% of standard resistance), a reformer can provide enough challenge to drive strength gains in most muscle groups. The variable resistance of springs also means the exercise gets harder as you push or pull further, which creates a unique loading pattern that’s gentle on joints but still demanding on muscles.
Who Benefits Most
Pilates works best as strength training for beginners, older adults, people recovering from injury, and anyone who hasn’t been doing regular resistance exercise. For these groups, the resistance is genuinely challenging, and the controlled movements reduce injury risk while still producing real strength improvements. The balance and coordination demands also provide neurological benefits that traditional weight training often misses.
For people who are already strong or who have specific goals like increasing their squat max, building visible muscle, or improving athletic power, Pilates alone won’t get them there. It can be a valuable complement to a weight training program, particularly for core stability, flexibility, and movement quality, but it can’t replace heavy resistance training for those goals.
The honest answer is that Pilates sits in a gray zone. It’s real strength training by public health standards, and the measured gains in force production back that up. But it’s not equivalent to lifting weights if your goal is maximal strength or hypertrophy. For general health, functional fitness, and meeting the recommended guidelines for muscle-strengthening activity, Pilates absolutely counts.