Also called: Acute back spasm; my back went out; locked back
Exercise strongly helps
Stretch
Massage
Strength
The back that goes out doing nothing much - bending to pick up a sock, sneezing, getting out of a car. It is a protective spasm rather than an injury, it is terrifying the first time, and it settles far faster with gentle movement than with bed rest.
How common: Most people with recurrent low back pain get episodes like this; it is the single commonest reason for an urgent primary-care back visit
What it is
This is acute muscle guarding. The nervous system decides the area needs protecting and splints it by locking the surrounding muscles on hard. The result is sudden, severe, gripping pain and a body that will only stand in one crooked position.
The severity is genuinely misleading. A locked back that has you calling for help off the bathroom floor is usually a spasm around a minor mechanical event, while a serious spinal problem often announces itself far more quietly. What the spasm is telling you is that the alarm has gone off, not that something has broken.
What it feels like
- A sudden catch or grab, often with a trivial movement, and then an inability to straighten up
- The body held bent and shifted to one side, because that is the only position that does not hurt
- Pain that is sharp on movement and a deep, gripping ache at rest
- Getting in and out of a chair or bed is the worst part of the day
- Coughing, sneezing or laughing sends a jolt through the area
What causes it
Most people have more than one of these at once, and they feed each other. Read the
list looking for the two or three that sound like your week rather than for the one
true answer — the ones that describe you are the ones worth acting on.
- A protective reflex, not a tear
- The muscles around a joint the nervous system has flagged will contract hard and stay contracted. Nothing has necessarily been damaged; the guarding itself is producing most of what you feel.
- The last straw on an already loaded back
- Almost nobody spasms out of nowhere. There is usually a fortnight of long drives, bad sleep, an unusual lift or a nagging ache first, and the sock on the floor is simply the movement that arrived when the margin had already gone.
- A cold, still, unprepared start
- The first bend of the morning, the first movement after two hours at a desk, or getting out of a car after a long drive all ask a stiffened system for a quick range with no warning.
- A trivial movement at an unusual angle
- Bending and twisting at the same time, reaching sideways into a car boot or lifting a child out of a cot puts a small load on the spine at an angle it never practises.
- A sudden internal pressure spike
- A hard sneeze or cough loads the trunk violently and involuntarily. If the deep trunk muscles are not braced ahead of it - and they usually cannot be - the load lands on the passive structures.
- Weak or fatigued trunk endurance
- The deep stabilisers are what stop a small perturbation becoming a big one. When they have no stamina left, the system has no fast correction available and falls back on the crude one: lock everything.
- A history of the same thing
- Once a back has spasmed, the nervous system is quicker to reach for that response next time. The threshold drops, which is why the second and third episodes often start from something even smaller.
- Stress, fear and a wound-up system
- Guarding is a threat response. A person who has been told they have a crumbling spine, or who is frightened of what the pain means, spasms harder and holds it longer than someone who understands what is happening.
Who tends to get it
- Anyone with a history of recurrent low back pain - this is the commonest way an episode starts
- People in a period of unusual load: a house move, a long drive, a stint of heavy lifting
- Anyone who has been sleeping badly or is under sustained stress
- People who were frightened by a previous episode, or by an alarming scan report
- Adults with no trunk or hip strength training in their week
What makes it worse, and what settles it
Makes it worse
- Bed rest, which measurably lengthens the episode
- Aggressive stretching into the spasm, which makes the guarding worse
- Staying frozen in one position for hours
- Panicking about what it means, which turns the guarding up
- Trying to push straight back to normal loading before the guarding has settled
Settles it
- Small, comfortable movements repeated often - little and often beats one big effort
- Heat over the area to reduce the guarding
- Gentle massage of the quadratus lumborum, glutes and upper back, which is where massage genuinely earns its place
- Walking as soon as walking is possible, even a few minutes at a time
- Knowing the episode is self-limiting, which lowers the threat and with it the spasm
What actually helps
The short version: Protective muscle guarding after a trivial movement - bending to pick something up, sneezing, getting out of a car. The spasm is the nervous system splinting the area, not damage to it
Strength work: Once the acute guarding settles: Core: Transverse Abdominis; Glutes: Max; Back: Spinal Erectors; Back: Lower Back
Stretching: AVOID aggressive stretching into the spasm; gentle Spine and Back: Lower Back in small ranges, little and often
Massage: Back: Quadratus Lumborum (QL); Glutes; Back: Upper Back - light, this is where massage earns its place, reducing guarding so movement can restart
Also worth doing: Heat; keep moving in small comfortable ranges; bed rest makes it worse and lengthens the episode
What the evidence says: Movement within comfort plus reassurance resolves most episodes in days. Massage genuinely helps here by reducing guarding. This is a different routine from back-pain prevention and should not be the same one.
The names above are the Targets qFIT tracks —
the Muscle Guide explains what each one does, and
Quick Add switches on the Exercises you
already have.
The qFIT routine for this
Ready-made routineBack Pain/Bulletproofing
qFIT already has this one built. It runs massage first, then stretching, then
strength — the order that works on a body that is already sore — and every
activity in it carries the reason it is there.
The button below opens your Checklist with this routine already selected, so instead
of your whole list you land on just its Categories, Targets
and Exercises, each with its checkbox, ready to tick as you work through
them.
Have more than one problem? Tick yours under My Problems on
My Profile and your Checklist's Routine list gains
Recommended for my problems — every routine for the problems you picked, merged
into one. Your picks stay private; that filter is the only thing they feed.
Get it checked if…
Bowel or bladder change, saddle numbness, leg weakness, fever, or spasm after significant trauma - urgent
And whatever the body part: chest pain or unusual breathlessness on
exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and
unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or
one calf that is swollen, warm and painful. Any of those, stop and get assessed.
How it usually goes
Most episodes turn a corner in two to four days and are largely resolved in one to three weeks. The crooked, locked stage is usually the shortest part. What matters afterwards is not stopping there: the episode is a signal that the margin had gone, so the weeks after it are when trunk endurance and glute strength are worth building - that work is prevention for the next one, not treatment for this one.
Prevalence basis: Primary-care presentation patterns
Others the same routine covers
These share the Back Pain/Bulletproofing routine, so the work is the same. If one of them also
sounds like you, that is a reason to expect more from it, not less.
This is general information, not a diagnosis, and it cannot examine you.
If it matches you, use it to ask better questions of a clinician rather than to replace one.