13/11/2025
Why You Shake During an Isometric — And Why It’s Actually a Good Thing
When you hold an isometric position (like a wall sit, plank, or a rehab hold), you might notice your body starts to shake or tremble.
Most people think this means they’re weak or doing something wrong.
But the truth is:
Shaking is your nervous system learning.
Here’s what’s really happening:
1. Your nervous system is upgrading its control system
During an isometric, your brain is trying to coordinate hundreds of tiny muscle fibres to maintain a still position. When it hasn’t quite mastered that pattern yet, the signals fire a bit “noisily.”
That “noise” looks like shaking.
This is your brain figuring out:
• How much tension to use
• Which muscles to switch on
• How to stabilise the joint
It’s literally motor learning in real time.
2. Your stabiliser muscles are switching on
Isometrics challenge the small, deep stabilising muscles that don’t normally get much attention.
When they’re recruited heavily, especially if they’re a bit untrained, they fire in quick bursts.
Those rapid-fire bursts = shaking.
3. Your body is building better force control
Maintaining a perfectly still hold under load is hard.
Your body must constantly adjust, like a camera stabilising a shaky image.
The wobble means you’re:
• Building joint stability
• Improving co-ordination
• Increasing neural drive
• Enhancing load tolerance
This is why isometrics are so powerful in rehab.
4. Shaking means you’re at the right level of challenge
If you never shake, the exercise might actually be too easy.
Shaking = you’re pushing into the zone where adaptation happens.
Your nervous system is being stimulated enough to change.
So, is shaking good?
Yes — as long as it’s not painful and you can keep good form.
Shaking means:
• Your nervous system is learning
• Your stabilisers are waking up
• Your movement control is improving
• You’re building resilience
It’s not a failure — it’s a sign you’re getting stronger.