Does Reformer Pilates Build Muscle? What the Evidence Says

Reformer Pilates does build muscle if you're new to resistance work, and it counts as strength training in the sense the NHS uses the term. It is a weak tool for building a lot of muscle, though, because the springs top out and you can't add load in small measured steps the way you can with a barbell or dumbbells. Most people who do two classes a week will get stronger through the trunk, hips and shoulders for the first few months and then plateau unless the work gets harder.

So the answer depends on what you mean by "build muscle". If you mean firmer, stronger and better at holding a plank, yes. If you mean visibly bigger quads and glutes a year from now, reformer work alone won't get you there.

How springs load a muscle

A reformer is a carriage on rails, held towards the footbar by springs. You push or pull the carriage away, the springs stretch, and your muscles work against that tension in both directions. That makes it resistance training by any reasonable definition.

A spring doesn't behave like a weight. A 10kg dumbbell weighs 10kg at every point of a curl, whereas a spring pulls harder the further you stretch it, so the load is lightest at the start of the movement and heaviest at the end. For footwork (the lying leg press that opens most classes) the springs are slackest when your knees are deeply bent, which is where a squat with a barbell is hardest. Your legs get the most resistance near lockout, where they're already at their strongest.

There's also a ceiling. Studio machines usually carry five springs, and once they're all hooked on, that's the maximum. Tensions aren't standardised between brands, so we won't quote kilogram figures for studio reformers. Budget home machines do sometimes publish them: TODO lists its folding reformer at four 22lb springs plus five 13lb cords, 153lb (about 69kg) in total at full stretch, per the listing. A healthy adult can leg press far more than that with two legs within a few months of training, which is why footwork stops feeling hard so quickly.

The upside of springs is the return. The carriage wants to snap back and you have to slow it down, so the lowering half of every rep is loaded. That is useful for muscle, and it's the part most people rush.

What the studies show

The research is more positive than sceptics assume and much thinner than studios imply.

The trial that ranks for this question is a 2025 randomised controlled trial in Scientific Reports. It put 47 overweight and obese women aged 30 to 60 into either reformer Pilates three times a week for 8 weeks or a control group. The reformer group improved grip strength and trunk endurance, lost body fat, and their muscle mass rose from 24.9kg to 25.6kg on average (Gökalp and Kirmizigil, 2025). That's roughly 0.7kg in two months, which is a real beginner gain. Two caveats matter. The team measured muscle with bioelectrical impedance scales, which are sensitive to hydration and less trustworthy than a DXA scan; and the participants were untrained, the group in whom almost any new resistance exercise adds muscle.

Pooled evidence is cooler. A 2026 systematic review and meta-analysis of 12 Pilates trials in roughly 540 adult women found significant drops in body weight and BMI and better flexibility, but no significant pooled effect on lean body mass, body fat percentage, handgrip strength or vertical jump (Sports, 2026). The authors add that individual studies point to better muscular strength and endurance, and they flag how varied the trials are. That review mixes mat and equipment Pilates, so it isn't a pure test of the reformer.

What about Pilates against other training? A 2022 systematic review of 11 randomised trials found no difference between Pilates and other exercise methods for dynamic strength, isometric strength or muscular endurance, and graded that evidence very low to low (Heliyon, 2022). Read it carefully: it says nobody has shown Pilates to be worse, in small and short studies, mostly in beginners and older adults. It doesn't show that a reformer matches a squat rack for a trained lifter, and no trial we could find has tested that directly.

Our reading of all three: reformer Pilates reliably improves strength endurance and core function, adds a little muscle to people starting from a low base, and has no evidence behind it for substantial long-term muscle growth.

Is reformer Pilates strength training?

For public health purposes, yes. The NHS tells adults to do strengthening activities that work all the major muscle groups on at least 2 days a week, and it names Pilates in its list of examples next to lifting weights and resistance bands (NHS physical activity guidelines).

The same page sets a condition that many classes miss. To get the benefit, you should do strength exercises "to the point where you need a short rest before repeating the activity". A flowing 45 minute class on light springs, where no muscle ever gets close to tired, is mobility work with a nice soundtrack. A class where your legs shake on the last four reps of a single-leg press counts.

For a lifter's definition of strength training, meaning progressively heavier loads over months, the reformer falls short. You can't add 1kg a week to a spring.

Which muscles it trains best

Reformer work is strongest where load matters less than control.

• Deep abdominals and obliques. Planks on a moving carriage, the hundred and kneeling work keep the trunk under tension for long stretches. Trunk endurance is the most consistent improvement in the trials.
• Glutes and hamstrings. Bridging, feet-in-straps work and side-lying leg presses load the back of the hips well, especially one leg at a time.
• Shoulder stabilisers and upper back. Rowing and pulling straps train the muscles around the shoulder blades with light, strict resistance.
• Inner thighs and hip stabilisers, which most gym programmes ignore.

It's weakest for the quads, chest and lats, the big muscles that need heavy loads to keep growing. Our reformer Pilates exercises guide covers the seven moves most classes are built on.

Reformer Pilates vs weights

	Reformer Pilates	Free weights
Type of resistance	Springs: light at the start, heavier as they stretch	Constant load through the whole rep
Maximum load	Capped by the springs fitted	Limited only by the plates you own
Progression	Coarse steps, one spring at a time, often unlabelled	Small measured jumps, 1kg to 2.5kg
Muscle growth	Small gains in beginners; no pooled effect on lean mass	Well established at every training level
Core and control	Excellent	Good, mostly as a by-product
Bone loading	Low: you're lying or kneeling, with no impact	Higher, particularly standing lifts
Joint stress	Low	Depends on load and technique
Cost	£15 to £30 a class, or about £250 upwards for a home machine	A pair of adjustable dumbbells covers most needs

The bone row deserves a sentence. The Royal Osteoporosis Society's advice is that bones respond best to a combination of impact exercise done on your feet and strength exercise that builds up gradually (ROS: exercise for bones). Most reformer work happens lying down against moderate tension, so it supplies little of the first and only some of the second. If bone density is a reason you exercise, add standing strength work and some impact.

How to build more muscle on a reformer

Muscle grows when sets are hard, and sets finishing close to failure appear to grow more than easy ones; we cover that research in our piece on whether resistance bands build muscle, which applies here because bands and springs share the same rising resistance. Four changes make reformer sessions harder.

1. Use heavier springs on leg and pulling work. If you finish 15 reps of footwork and could have done 15 more, the setting is too light for muscle. Add a spring until the last three reps slow down.
2. Slow the return. Take three to four seconds to let the carriage come home. You get more time under tension from the same spring, and it's the part of the rep where springs are most useful.
3. Train one side at a time. Single-leg footwork, single-leg bridges and one-arm rows roughly double the demand on the working limb without needing a spring the machine doesn't have. This is the best fix for the load ceiling.
4. Work to a rep target, not the clock. Count reps, write down the spring setting, and try to beat it next week. Instructors rarely ask for this; nothing stops you doing it anyway.

Even with all four, you'll reach a point where single-leg footwork on full springs is comfortable for 20 reps. That's the machine's limit.

A sensible weekly mix with weights

You don't have to choose. The two fill each other's gaps, and three or four sessions a week is enough.

• Two reformer sessions, 45 to 60 minutes, run with the rules above. These cover core, hips, shoulder control and mobility.
• One or two weights sessions, 30 to 40 minutes. Four movements do the job: a squat or lunge, a hip hinge such as a Romanian deadlift, a press and a row. Do 3 sets of 6 to 12 reps and add weight when you hit the top of the range.
• Something with impact on another day, such as brisk hill walking, jogging or skipping, if bone health matters to you.

A pair of adjustable dumbbells is enough equipment for the weights sessions and takes up less floor than a yoga mat. If you'd sooner not own weights, a set of resistance bands will handle the rows and presses, though they share the spring's limits on heavy leg work.

Home reformers

Studio classes cost £15 to £30 each in most of the UK, so twice a week runs past £1,500 a year. A folding home machine pays for itself quickly if you'll use it, and our breakdown of how much a Pilates reformer costs sets out the price tiers.

For muscle, the question to ask of any home reformer is how much resistance it has. Cord-only machines are the weakest, and spring machines with published tensions are easiest to progress on. The TODO folding reformer is one of the few budget models that states its numbers (153lb across four springs and five cords), and it costs around £285 at the time of writing. It only suits users up to about 5ft 9in, so taller readers should look at the ZERELEK or the other machines in our best Pilates reformer UK guide.

Check price on Amazon£284.99

The verdict

Reformer Pilates builds a modest amount of muscle in beginners, a lot of core endurance in almost everyone, and meets the NHS strengthening guideline when you work hard enough to need a rest between sets. It won't keep building muscle for years, and it does little for your bones. Keep the reformer for what it does well and lift something heavy once or twice a week for the rest.

Recommended reads

• The best Pilates reformers in the UK
• Reformer Pilates exercises for beginners
• How much does a Pilates reformer cost?
• Do resistance bands build muscle?
• The best adjustable dumbbells in the UK