A muscle strain is a muscle or tendon that has been overstretched or torn, which is why people also call it a pulled muscle. A sprain is the same kind of injury in a ligament, the tissue that holds bones together at a joint. Back strains are common, and one usually follows a lift or an awkward twist.
A strain is graded by how much of the muscle is damaged
Strains are graded from 1 to 3: in grade 1 the muscle is overstretched and slightly damaged, grade 2 is a partial tear that leaves it weaker and harder to move, and grade 3 is a complete tear. A complete tear can take months to recover from and may need surgery.
A strained back muscle hurts most when you bend or stand up
The pain usually starts during the lift or soon after. The back muscles do the work every time you bend forward or get up from a chair, and pain that worsens with movement is one of the main symptoms of a back strain. Numbness or weakness in a leg is not usually part of a strain; it suggests a nerve is involved and needs a doctor.
Neck muscles strain too, though after a crash a doctor needs to see the neck first, as our article on why whiplash pain often starts a day later explains.
A back spasm is a muscle tightening on its own, often on top of a strain
A spasm is a sudden, involuntary tightening of a muscle, and that painful clench is a common symptom of a strain. A strain is damage to the tissue, while a spasm is something the muscle does, with or without a strain behind it. Some spasms are a mere twitch, and others grip hard enough to stop you mid-step.
The NHS suggests an ice pack for pain and swelling and a heat pack for stiffness or spasm, each wrapped in a towel.
Long spells in bed are discouraged, and heavy lifting returns gradually
Lying still feels like the obvious answer to a muscle that hurts when it moves. The NHS advises staying active instead, and the NICE guideline on low back pain asks clinicians to encourage people to carry on with their normal activities.
MedlinePlus advises against heavy lifting and twisting in the first weeks after the pain begins. Rushing back to full training as soon as the pain fades is one of the mistakes athletes make with sports injuries.
Pain that runs below the knee or wakes you at night points beyond a muscle
MedlinePlus lists both among its reasons to contact a doctor straight away, along with a history of cancer, and the NHS advises seeing a doctor about pain that does not ease with rest or weight loss you cannot explain.
Strain heads our list of seven common causes of back pain, and our guide to lower back pain covers the wider picture, including nerve pain.
Measurement comes before any treatment, and warning signs send you to a doctor first
At The Sync, SpinalSync tests each segment of the spine on its own, with the readings on a screen as they are taken, and measuring again at later visits shows what is changing. MyoSync works with fascia and soft tissue, including muscle tension and reduced mobility. Treatment is gentle by design, with instrument-guided, low-force input for anyone who prefers not to be manually adjusted, and the aim is to support comfort and movement.
The Sync does not diagnose, prescribe medication, inject, operate, or provide or read imaging. If something needs a doctor, a Sync specialist will say so early. Our back pain page explains how the assessment works.
Common questions about muscle strain
It depends on how badly the muscle is damaged. The NHS says most strains feel better after two weeks, though a severe one can take months to recover. See a doctor if your back is not improving with home care.
Usually not. NICE advises against routine imaging for low back pain outside specialist care, and keeps scans for cases where the result would change what happens next. Whether you need one is a doctor's call.
Gentle stretches are part of the NHS self-care advice for back pain, and it helps to bring movement back in after the first few days. Stay within what the pain allows rather than pushing through it. If a stretch sends pain or tingling down a leg, stop and see a doctor.
See a doctor first if you have numbness, weakness, a fever, a change in bladder or bowel control, or pain that began after a fall or crash. Otherwise a Sync specialist can measure how your back moves and will tell you early if anything needs a doctor. The Sync does not diagnose, prescribe medication, inject, operate, or provide or read imaging.
Written by the Aphyx Content team, reviewed by the clinical team at The Sync. Published 26 October 2026. Last updated 26 October 2026.