Why Pilates Isn't Enough

Doug Joachim
Sep 19
6 min read

Look, I get it. Pilates is trendy, fun, and makes you feel like you have a sophisticated dancer body. It's the kale of the fitness world, everyone talks about how amazing it is, and there's definitely some truth to the hype. But here's the thing that's going to ruffle some perfectly aligned spines: Pilates alone isn't going to give you the thin lean muscle you're probably hoping for.

Before the Pilates mafia comes for me with their 'Reformers', let me be crystal clear: I'm not anti-Pilates. It's fantastic for core strength, mobility, and making you more aware of muscles you forgot existed. But if your goal is building significant lean muscle mass, especially as a woman navigating the hormonal roller coaster of life you're going to need something with a bit more... oomph.

A Brief History Lesson

Let's talk about how we got here. Joseph Pilates was born in 1883 in Germany as a sickly child who suffered from asthma, rickets, and rheumatic fever. He dedicated his life to improving his physical condition, eventually developing his method, which he called "Contrology," during World War I while interned in a camp. In 1926, Joseph and Clara Pilates set up the first Pilates studio on Eighth Avenue in New York City, attracting a varied and diverse clientele, including the elite.

Here's where things get interesting from a marketing perspective. By the 1960s, Pilates became an accepted part of a dancer's training regimen, and the association with dancers cemented its reputation for creating that coveted "dancer body." Fast forward to today, and women (and some men) are seeking that long and lean look that's been marketed as the Pilates promise.

The problem? This "long and lean" marketing is brilliant but biologically impossible. Your muscle fibers can't grow longer they can only grow bigger. But tell that to decades of marketing that convinced women that weight training would make them bulky and stiff while Pilates was the secret to a ballet dancers' body.

The Science of Getting Strong

Muscle grows when you give it real mechanical tension, with metabolic stress and a dash of muscle damage playing supporting roles. The primary driver is mechanical tension. Contract a muscle against meaningful load, you light up mechanosensors, mTORC1 gets chatty, protein synthesis goes up, fibers get thicker, and you look better in a T-shirt. Keep that signal alive with progressive overload: add load, add reps, add sets, and don't forget about effort! Classic reviews cover the science in detail (Schoenfeld 2010, Wackerhage 2019)

In previously inactive adults, about 10 weeks of resistance training averages roughly plus 1.4 kilograms of lean mass, minus 1.8 kilograms of fat, and plus 7% resting metabolic rate, according to Westcott’s summary (2012). A meta-analysis using indirect calorimetry shows resistance training raises resting metabolic rate by about 96 kcals per day compared with control, while aerobic training alone shows no clear change (MacKenzie-Shalders 2020). Lab work in older men finds similar bumps (Pratley 1994). And if that is not enough, lifting also improves bone density and brain health in older adults (Liu Ambrose 2010). That is a lot of wins for picking up heavy things up and putting them down.

Pilates, on the other hand, is excellent for control, alignment, and moving like a calm panther. It may reduce body fat in some groups (not as well as weight training) and lean muscle gains are usually small or none (Wang 2021). Typical Pilates sessions are about 3 METs, which is moderate work that limits peak tension on the bigger muscles (2011 Compendium). Springs, straps, and body weight are useful tools, but they cap how heavy you can go. Without progressively heavier loads, increased tension the hypertrophy signal fades.

So if “match that” means adding a solid pound of muscle and nudging your metabolism upward in just a few months, progressive resistance training is the proven and superior path. Pilates is still valuable but barbells, dumbbells, and machines pay the “tension rent” your muscles demand. And while we are myth busting, hypertrophy makes fibers thicker, not longer. Muscles do not lengthen like a Stretch Armstrong toy. What most people call “long lean muscles” is usually just more muscle plus better flexibility (Lim 2022, Weppler and Magnusson 2010).

The Progressive Overload Problem

Here's where Pilates hits a wall (and not the fun kind with springs). To build lean muscle mass, you need progressive overload consistently challenging your muscles with increasing resistance over time.

Pilates is brilliant at teaching you to control your body weight and improve small movements and strengthen the core, but it has inherent limitations when it comes to loading. Sure, you can add resistance with bands, springs, and various torture devices that look like they belong in a medieval dungeon, but you're still working within a relatively narrow resistance range. Weight training, on the other hand, lets you progressively add more weight to the bar, dumbbells, or machines. This week you squat 100 pounds, next month you're squatting 110. That's the kind of progressive challenge your muscles need to grow.

What Pilates IS Great For

Don't get me wrong – Pilates isn't useless. It's actually fantastic for:

Core stability and strength: Your deep core muscles will thank you
Mobility and flexibility: Supple leopard
Body awareness: Suddenly you'll notice when your left hip is being dramatic
Injury prevention: When done correctly, it can help you move better and hurt less

Think of Pilates as the vegetables of your fitness routine: important for overall health, but you need some protein (aka weight training) to build the muscle you're after.

The Hormonal Reality Check

As female estrogen levels fluctuate and eventually decline (thanks, Mother Nature), maintaining and building lean muscle mass becomes increasingly challenging. Protein becomes crucial not only because it floods muscles with leucine, which triggers lean mass building, but also because increased amino acids help with metabolism and brain recovery.

But here's the kicker: you can eat all the protein in the world, but without adequate resistance training stimulus, you're not going to maximize that muscle-building potential. Pilates simply doesn't provide the mechanical tension necessary to trigger significant muscle protein synthesis.

The Bottom Line

If your goals include:

Building significant lean muscle
Increasing bone density
Boosting metabolic rate
Getting stronger (not just more flexible)

Then Pilates alone isn't going to cut it. You need to pick up heavy things and put them down repeatedly.

But (and this is a big 'butt' and I cannot lie), the ideal approach isn't choosing between Pilates OR weight training. It's Pilates AND weight training. Use Pilates to improve your movement quality, core stability, and mobility, then use weight training to build the lean muscle mass that'll keep you strong and metabolically healthy.

Your Action Plan

Keep doing Pilates if you love it BUT just don't expect it to be your muscle building solution
Add 2-3 weight training sessions per week focusing on compound movements
Eat adequate protein – aim for at least 1.6-2.2g per kg of body weight (or for Americans: .7 - 1 g per pound)
Be patient – building lean muscle takes time, especially for women

The Final Word

Look, any exercise is better than no exercise. If you absolutely love Pilates and it's the only thing that gets you moving consistently, then keep at it. Movement is medicine, and consistency trumps perfection every single time.

But let's be real about expectations. If you're doing Pilates exclusively, that's fantastic for your overall health and well being. Just don't expect large advances in strength, lean muscle, and bone density. It's like trying to drive cross country in a bicycle. Sure, you'll get there eventually, but it's going to take a whole lot longer and you might not reach the destination you had in mind.

The beauty is in knowing what tool works best for which job. Pilates excels at movement quality and core stability. Weight training excels at building muscle and bone strength. Choose based on your goals, not based on what looks pretty on Instagram.