Why Do Muscles Spasm? The Body’s Built-In Protective Reflex
If you’ve ever felt a sudden, sharp cramp or a muscle that "locks up" unexpectedly, you've experienced a muscle spasm. Whilst they're painful, spasms aren't random, they're part of the body's clever defence system.
Sometimes we feel like we've pulled or strained a muscle because it suddenly becomes painful, even by doing innocuous things...
This happened to my lower back when I was waxing my surfboard. How can I "pull" a muscle or damage my spine by waxing a surfboard, when I can deadlift a significant amount of weight?! There was no excessive load to damage the tissue beyond what my body can handle, so how can this be?
Let's dive into it...
Firstly, what is a muscle spasm?
A muscle spasm is an involuntary contraction of muscle fibres. Unlike a controlled movement where you decide to lift your arm or walk across the room, a spasm happens without conscious thought. It can last for just a few seconds or linger for minutes, often leaving soreness behind.
Why do spasms happen?
At their core, spasms are a protective mechanism. These are the roles that muscle spasms play:
1. Preventing Injury
When the body senses that a muscle or joint is at risk of overstretching, nerves send rapid signals that cause the muscle to contract suddenly. This reflex contraction acts like a brake, stopping you from moving into a range that could damage tissues or joints.
2. Responding to Fatigue
Overused or fatigued muscles may spasm because they lack enough energy or electrolytes to contract and relax properly. By "locking up," the muscle discourages further use, forcing rest before more damage can occur.
3. Guarding Injured Areas
If a tissue is already injured for example, after a back strain the surrounding muscles may spasm to create a natural splint. This tension reduces motion in the area, helping to protect delicate structures while they heal. This can also be retrospective in the sense that your nervous system remembers a certain way you became injured in the past and similar movements can trigger this guarding response as a pre-emptive measure.
4. Signalling a Problem
A spasm often acts as an alert system. It's your body's way of drawing attention to nerve irritation, an underlying injury, or dehydration/electrolyte imbalances often referred to as EIMC's (exercise induced muscle cramps). This is slightly different to the movement guarding pain.
The double-edged sword.
While spasms can protect you in the short term, chronic or recurring spasms may backfire. Prolonged muscle tightness can restrict movement, increase pain, and set off a cycle of dysfunction. Shoulders are the worst for this by the way!
Your nervous system is like an overprotective parent, you need to show it that you're responsible, so it calms down its protective measures. That's why strengthening your muscles is so important to rehab injury because you're giving your nervous system feedback that you can move in certain ways and you are able to stabilises joints in certain ranges and under certain loads. It makes you less prone to defensive overreactions in the future.
Your nervous system remembers every little thing that causes you pain or injury, it's why when we get older taking a 20 minute nap on the sofa can leave you with "Batman neck" when you wake up (If you don't get that, watch a clip of Batman trying to turn his head in costume...) because we encounter more injuries as we get older the nervous system becomes more reactive.
Often these spasms occur because of environmental, psychological and sociological factors. As I previously mentioned, I injured my back waxing my surfboard, why did this happen? Most likely it was because it was 5 days after my Dad sadly passed away, so there was definitely a lot of stress and emotion that my body was going through and trying to deal with. I'd had a previous "actual" injury to that region and as it was the weakest link, it was my body telling me to stop.
Considerations to take away.
Muscle spasms might feel inconvenient or even alarming but they're rarely random. It's also recognising that because you bent over too quick to tie your shoelaces or reached for a box in the cupboard, that you actually haven't injured yourself. It's your body's built-in safety reflex, acting as a guardian against potential injury.
If you do encounter a muscle spasm you must gently reintroduce pain free movement and load bearing exercises to reassure your nervous system that your body is safe and capable. You must gradually progress your way out of pain and stiffness to give a permanent reduction in protective muscular spasms.
The key is listening to your body: when your muscles spasm, it's your body usually asking for rest/better sleep, recovery from illness, better nutrition/hydration, removal of/the ability to deal with environmental stressors or paying attention to a deeper issue.
If you suffer with frequent spasms, feel free to get in touch so I can point you in the right direction to help you overcome them long term.
I hope this helps!
