You’re halfway through a Pilates exercise when suddenly your legs start shaking.
Or perhaps it’s your abdominal muscles.
Maybe you’re holding a position on the Reformer and your thighs seem to have developed a mind of their own.
The good news?
Muscle shaking during Pilates can be completely normal, particularly when an exercise is challenging, unfamiliar or your muscles are beginning to fatigue.
And no — it doesn’t automatically mean you’re weak or “bad at Pilates.”
In fact, strong and experienced people can shake too.
But there’s more to it than the popular fitness advice to simply “embrace the shake.”
Shaking isn’t proof that you’ve activated a particular deep muscle. It doesn’t automatically mean you’re performing an exercise perfectly. And you certainly don’t need to shake for Pilates to be effective.
The shake is simply information about how your body is responding to the task.
So why does it happen?
Let’s look at the science behind those trembling thighs — and what you should actually do when it happens.
Why Do Muscles Shake During Pilates?
Your muscles don’t work independently of your nervous system.
To create and control movement, your nervous system coordinates the activation of motor units — the motor neurons and muscle fibres involved in producing force.
When an exercise becomes demanding or fatigue begins to develop, maintaining that force perfectly steadily can become more difficult.
As fatigue develops, changes in motor-unit behaviour, sensory feedback and the mechanical properties of the working muscles can contribute to changes in force steadiness and the trembling you feel.
This phenomenon isn’t unique to Pilates.
Exercise-related physiological tremor has been studied during different types of physical exertion and fatiguing muscular contractions.
A recent systematic review and meta-analysis examined 28 experimental studies involving healthy adults and found that physiological tremor can change following physical exertion, with the majority of studies reporting increased tremor amplitude after resistance-based or fatiguing exercise.
So yes, the shake is real.
But the physiology behind it is considerably more interesting than simply saying your “deep muscles are waking up.”
What Is Physiological Tremor?
All of us have a small amount of involuntary movement known as physiological tremor.
Most of the time, it’s so subtle that you don’t notice it.
Physical exertion, muscular fatigue and other factors can make this trembling more noticeable.
Physiological tremor isn’t generated by one single mechanism.
Researchers describe it as being influenced by interacting mechanical and neurological factors.
That matters because it helps explain why there isn’t one simple explanation for every shake you experience during exercise.
And importantly, experiencing some muscle trembling during a challenging exercise doesn’t automatically mean something is wrong.
Why Does Pilates Make Your Muscles Shake?
Pilates can create some particularly interesting conditions for muscle trembling.
Movements are often performed slowly and deliberately.
You may spend considerable time under muscular tension.
Some exercises require you to hold a position while another part of your body moves.
Others demand precise control rather than momentum.
And on the Reformer, you may also be controlling a moving carriage while working with or against spring tension.
Sometimes an exercise barely looks as though you’re moving.
Meanwhile, your muscles have very different opinions about the situation.
That’s part of what makes Pilates so interesting.
A movement doesn’t have to be big, fast or high impact to be challenging.
Does Shaking Mean Your Muscles Are Weak?
Not necessarily.
This is one of the most reassuring things to understand if you’re new to Pilates.
You can be strong and still shake.
You can be fit and still shake.
You can have years of Pilates experience and still encounter an exercise that makes your muscles tremble.
The demand of an exercise can change considerably when you alter your body position, resistance, duration, range of movement, stability, lever length or the exercise itself.
A person can therefore be very capable in one movement and find another surprisingly challenging.
Strength isn’t one universal quality that makes every exercise easy.
Why Do Beginners Shake During Pilates?
If you’re new to Pilates, you may notice shaking more often simply because you’re being asked to do things your body isn’t accustomed to.
You’re learning new movements.
You’re learning how to position yourself.
You’re learning how to control the movement rather than simply complete it.
And you’re often trying to listen to your instructor while simultaneously wondering where your leg is supposed to be.
That’s a lot happening at once.
As you practise, movements can become more familiar. Your coordination can improve. Your muscular endurance may develop. And exercises that initially felt enormously challenging may eventually feel much more manageable.
That’s progress.
Does Shaking Mean Pilates Is Working?
Shaking can tell you that an exercise is challenging your current ability to produce or control the required movement.
But shaking itself isn’t proof that you’ve had an effective workout.
You can perform an excellent Pilates session without shaking once.
Likewise, shaking doesn’t prove that you’ve perfectly activated a particular muscle.
You don’t need to chase it.
The shake isn’t the goal. The movement is.
MYTH: Shaking Means Your Deep Muscles Are “Waking Up”
This is one of those Pilates explanations that sounds fantastic.
But scientifically, it’s too simplistic.
Pilates exercises can certainly challenge muscles involved in trunk stability, joint control and movement.
What we can’t do is look at somebody’s trembling leg and confidently announce that their “deep stabilisers have finally switched on.”
Visible shaking doesn’t tell us which individual muscles are working or whether an exercise is being performed correctly.
Physiological tremor involves interactions between the muscles, nervous system, sensory feedback and mechanical properties of the body.
Your body is much more sophisticated than:
Shake = deep muscles activated.
And that’s actually more interesting.
MYTH: The More You Shake, the Better the Workout
No.
There is no prize for becoming the shakiest person in the Pilates studio.
Shaking may appear when an exercise becomes challenging. That doesn’t mean more shaking automatically produces better results.
Technique matters.
Progression matters.
Exercise selection matters.
Consistency matters.
And your ability to control the movement matters.
Shaking is information. It isn’t a score.
Why Do Your Legs Shake During Reformer Pilates?
This is probably one of the most common places you’ll experience the Pilates shake.
During Reformer exercises, your legs might be pushing the carriage against spring resistance, controlling the carriage as it returns, holding your body in position, working independently from one another or helping stabilise you while the carriage moves.
As the task becomes more demanding or fatigue develops, maintaining smooth force and control may become more difficult.
That’s when your quadriceps, glutes, hamstrings or calves may start trembling.
And sometimes it happens rather dramatically.
One repetition feels perfectly manageable.
The next brings a tiny wobble.
Then suddenly your thighs appear to be communicating in Morse code.
It’s often simply a sign that the exercise has become challenging relative to your current capacity.
Why Do Your Thighs Shake During Pilates?
Your thighs can shake during exercises involving squatting patterns, lunges, footwork, bridges and sustained positions.
These movements can place significant demands on the muscles surrounding your hips and knees.
You may particularly notice trembling toward the end of a set or during a sustained position.
That doesn’t mean your thighs are weak.
It means the exercise is presenting a challenge.
As your capacity develops, that same exercise may eventually produce considerably less trembling.
Why Do Your Abs Shake During Pilates?
Your abdominal muscles can shake for similar reasons.
Many Pilates exercises ask your trunk to maintain a position while your arms or legs move.
Changing the position of your limbs can change the mechanical demand placed on your body.
That’s why you might feel completely comfortable in one position and suddenly start trembling when your instructor asks you to extend your legs a little farther.
Again, the shaking isn’t evidence that you’ve discovered a magical “deep core.”
It simply tells you that maintaining the position has become challenging.
And if you’re not quite sure what “engaging your core” is supposed to feel like in the first place, we’ve explained what core engagement actually means in Pilates — including breathing, bracing and why you don’t need to suck your stomach in.
Why Do You Shake During Pilates Holds?
Static or near-static holds can make muscle trembling particularly noticeable.
Imagine holding a challenging position.
Your muscles need to continue producing enough force to maintain it.
As the contraction continues and fatigue develops, maintaining perfectly steady force may become more difficult.
Experimental research into sustained muscular contractions has demonstrated changes in tremor and motor-unit behaviour as fatigue develops.
So if you begin a Pilates hold feeling perfectly composed and finish it wondering why every muscle is vibrating, you’re certainly not alone.
Why Can Lighter Reformer Springs Make You Shake More?
This is one of the most interesting things about Reformer Pilates.
People often assume:
More springs = harder.
But that’s not always how the Reformer works.
In some exercises, increasing the springs increases the resistance you need to overcome.
In other exercises, the springs are also providing assistance or support.
Depending on the exercise, lighter springs may provide less resistance or assistance and change the stability and control demands of the movement.
That can sometimes make an exercise feel considerably more challenging.
It’s why you shouldn’t automatically assume your instructor is making an exercise easier when they remove a spring.
The exercise has changed.
We’ve explained exactly how the Reformer and its spring system work in our complete guide to Reformer Pilates.
Should You Keep Going When Your Muscles Start Shaking?
Often, a little muscle trembling during a challenging exercise isn’t automatically a reason to stop.
The more useful question is:
Can you still perform the exercise with reasonable control?
Can you maintain an appropriate position?
Can you continue breathing?
Does it feel like muscular effort rather than pain?
If so, you may be perfectly comfortable continuing.
But you don’t need to prove anything either.
If the shaking becomes so pronounced that you’re losing control of the movement, that’s useful information.
Modify. Rest. Reset.
Then continue when you’re ready.
Good exercise isn’t about ignoring your body. It’s about learning how to work with it.
What Should You Do if You’re Shaking Too Much?
Depending on the exercise, your instructor might change your range of movement, resistance, body position, lever length, duration or exercise variation.
Or you might simply take a moment to rest.
There is nothing wrong with modifying an exercise.
In fact, choosing the version you can perform well is often far more productive than battling through a version you can no longer control.
Rest isn’t failure. It’s part of training.
Shaking vs Muscle Burning: Are They the Same Thing?
Not exactly.
A burning sensation during demanding exercise and visible muscle trembling are different experiences, although they can certainly happen at the same time.
The familiar “burn” during muscular work is associated with metabolic changes occurring during exercise.
Trembling involves fluctuations in force and neuromuscular control.
You may experience one without the other.
And neither needs to be maximised for your Pilates session to be worthwhile.
Is Shaking During Pilates a Sign You’re Getting Stronger?
Not by itself.
Strength develops through training and adaptation over time.
One spectacularly shaky set doesn’t prove that you’ve suddenly become stronger.
Instead, look at what happens over weeks and months.
Perhaps an exercise that once felt impossible becomes manageable.
Perhaps you can maintain better control.
Perhaps you can use a more challenging variation.
Perhaps your movement feels smoother.
Perhaps you can complete more of the class without needing to rest.
Those changes tell us considerably more about progress than whether your thighs shook during Tuesday morning Pilates.
Why Might You Stop Shaking as You Get Better at Pilates?
Your body adapts.
When you’ve practised a movement repeatedly, your ability to perform it may improve.
You may become stronger. Your muscular endurance may improve. Your coordination may become better. And the exercise itself may simply feel more familiar.
Something that once had your legs trembling after three repetitions might eventually feel completely comfortable.
That doesn’t mean Pilates has “stopped working.”
It may mean you’re ready for another challenge.
Resistance can change.
Range can change.
Tempo can change.
Stability can change.
The exercise can change.
Your Pilates can grow with you.
Do Experienced Pilates Clients Still Shake?
Absolutely.
Because there is always another way to create challenge.
An experienced Pilates client may perform one exercise beautifully and then encounter a different variation that immediately exposes a new challenge.
That’s one of the things that can keep Pilates interesting long term.
As you become better at Pilates, you don’t simply repeat the beginner exercises forever.
Your training can progress with you.
When Is Shaking During Exercise NOT Something to Push Through?
There is an important difference between a particular muscle trembling during a demanding exercise and feeling generally shaky or unwell.
If you experience symptoms such as dizziness, faintness, chest pain, unusual shortness of breath, confusion, significant weakness or generally feeling unwell, stop exercising and tell your instructor.
Likewise, sudden or significant pain isn’t something to celebrate as part of “the shake.”
If shaking happens outside exercise, persists unexpectedly or concerns you, speak with an appropriate healthcare professional.
Exercise should challenge you.
That doesn’t mean ignoring symptoms that don’t feel right.
What if I Shake During My First Pilates Class?
You’re allowed to.
You might shake.
You might get your left and right mixed up.
You might forget which strap you’re supposed to use.
You might need to stop and look at your instructor.
None of those things means you aren’t suited to Pilates.
Your first classes are for learning.
If you’re thinking about starting but feeling a little nervous, read our Pilates for Beginners guide to find out exactly what to expect from your first class.
Does Shaking Mean You Need to Do Pilates More Often?
No.
One shaky Pilates class isn’t your body issuing instructions to book five more.
How often you should practise depends on your goals, experience, recovery and the rest of your exercise routine.
For many people, consistency is far more important than trying to do as much Pilates as possible.
We’ve covered this in our guide to how often you should do Pilates to see results.
What Does the Research Say About Muscle Shaking and Exercise?
The science of physiological tremor is much more interesting — and much more complicated — than many fitness explanations suggest.
A systematic review and meta-analysis examining physiological limb tremor following physical exertion included 28 experimental studies in healthy adults.
The majority of studies reported increased tremor amplitude following resistance-based or fatiguing exercise.
However, the researchers also found considerable differences between studies, including how tremor was measured, when it was measured and the type of exercise performed.
That means we shouldn’t turn the research into another overly simple rule.
Read the systematic review: Physiological Limb Tremor Modulation by Physical Exertion
Earlier experimental research has also demonstrated relationships between fatigue, motor-unit activity and increasing physiological tremor.
One study found increasing tremor amplitude as fatigue progressed during a sustained task, accompanied by changes in motor-unit activity and synchronisation.
Together, the research supports a much more nuanced explanation than “shaking means your deep muscles are working.”
Physiological tremor reflects interactions between mechanical and neurological factors, and physical exertion can alter it.
What the research does not tell us is that shaking during a Pilates class is a badge of success.
And that’s an important distinction.
The Good News About the Pilates Shake
If you’ve been worried that shaking means you’re too weak for Pilates, you can stop worrying about that.
Shaking can happen to beginners.
It can happen to experienced clients.
It can happen during Mat Pilates.
It can happen on the Reformer.
And it can happen when an exercise simply presents your body with a new challenge.
You don’t need to fear the shake.
You don’t need to chase it either.
Notice it.
Stay in control.
Modify when appropriate.
And keep building from where you are.
What We Tell Beginners at Bodi Boutique
At Bodi Boutique, we don’t expect you to walk through the door already strong enough to perform every exercise.
That’s not how learning works.
Our Pilates approach follows three stages:
LEARN.
Learn the movements, understand your body and develop your technique.
GROW.
Build strength, control, confidence and capacity as your Pilates progresses.
FLOW.
Bring those skills together as movements become more familiar, confident and fluid.
Somewhere along the way, your legs might shake.
That’s okay.
You’re learning what your body can do.
Ready to Try Pilates in Millmerran?
If you’ve been considering Pilates but worrying that you aren’t fit, strong or coordinated enough, you don’t need to become “Pilates ready” before you begin.
You begin to become ready.
At Bodi Boutique, we offer small-group Pilates and Reformer Pilates in Millmerran, helping women learn the movements, understand the equipment and progressively build confidence and ability.
Explore Pilates & Reformer Pilates at Bodi Boutique
You May Also Like
Pilates for Beginners: What to Expect From Your First Class
What Is Reformer Pilates? How It Works, Benefits & What to Expect
How Often Should You Do Pilates to See Results?
Mat Pilates vs Reformer Pilates: Which Is Better for You?
Related Bodi Boutique guidance
About the Author
Jazz — Bodi Boutique
Jazz is a qualified fitness and Pilates instructor and the owner of Bodi Boutique, a small-group fitness, Pilates, Reformer Pilates and wellness studio in Millmerran, Queensland.
Through Bodi Boutique, Jazz works with women across different ages, fitness levels and exercise backgrounds, with a focus on making movement approachable, progressive and enjoyable.
