Acute Back Pain:
When Your Back Locks Up.

October 2026 · 8 min read · Back Pain Guide

PEMF — pulsed electromagnetic field therapy from PainFree — brings a new approach to back pain: a focused technology that reaches deep into the locked-up muscles, with no needles, injections or medication, together with the physiotherapy and exercises you already do.

• ✓ Get out of bed in the morning without a locked back
• ✓ Sit and drive without calculating every movement
• ✓ Lift your children without fear

🔬 Backed by research: 14 controlled trials, 618 patients — less low back pain than with a placebo treatment, especially when the pain has lasted for months (see the study).

🎖️ What the Experts Say: The Medical and Rehabilitation Backing Behind the Technology

What senior figures in Israeli medicine, rehabilitation and public health say about pulsed electromagnetic field (PEMF) technology — from their reviews, opinions and clinical experience:

• The medical-clinical view | Prof. Gabi Zeilig, retired Director of the Neurological Rehabilitation Department, Sheba Medical Center, Tel Hashomer. In a medical review he wrote on the technology he concludes: “There is no doubt there is a place for integrating PEMF technology into rehabilitation treatment in populations suffering from pain and functional impairment.” Read the full review
• The safety and regulatory view | Prof. Itamar Grotto, former Associate Director General of the Ministry of Health and Head of Public Health Services. In the opinion he wrote on bringing the technology into Israeli health institutions he notes: “Negligible side effects, with no heat generation or significant biological risk.” Read the opinion
• The functional and rehabilitation view | Uria Moran, physiotherapist, Lt. Col. (res.) and former Commander of the IDF Physiotherapy Array. He leads the professional training of PainFree therapists: how to use the pulses to break the pain cycle, so the patient can get back to exercising and moving.
• The pain-medicine view | Dr. Moasi, senior pain physician at Sheba Medical Center and at the Clalit pain clinic in the Hadera–Karkur area. He has been using PainFree’s pulsed electromagnetic technology in his clinic for more than 5 years.

The reviews above concern PEMF technology; this page was written by the PainFree editorial team.

What Is Acute Back Pain (a Back Spasm) — and Why Does Your Back Lock Up Right Now?

“My back went out” — almost everyone has said this at least once in their life. A back spasm (medically: acute low back pain; popularly known as lumbago) is a sudden, sharp pain in the lower back that usually arrives in a single moment: bending to tie a shoelace, lifting a laundry basket, twisting the body quickly, a hard sneeze, or getting up after hours of sitting at the computer.

What actually happens is that the muscles running along the spine go into a protective contraction. The body “locks” the area to protect it, and the result is a stiff back, pain that worsens with every movement and a feeling that you cannot straighten up. Sometimes the source is a strained muscle or ligament, sometimes the small joints between the vertebrae, and sometimes simply a load that built up over weeks and “exploded” at the wrong moment.

The good news? In most cases a back spasm is not a sign of serious damage to the structure of the spine. It hurts a lot, it is frightening — but it is not your fate.

How to recognise a back spasm:

• Sharp pain in the lower back, sometimes on one side only
• Difficulty straightening up after bending
• Walking “crooked” or the body leaning to one side
• Pain that worsens when getting out of bed, sitting, coughing and sneezing
• Hard muscles along the back that are tender to the touch

How Long Does Acute Back Pain Last — and When Is It No Longer “Just a Spasm”?

In most cases a back spasm eases gradually: the first days are the hardest, and over the following days and weeks the back starts moving again. The accepted recommendation today is to stay as active as the pain allows, and not to lie in bed for whole days.

But there is another side, and anyone who has lived it knows it well: for some people the pain never fully goes away, or it keeps coming back — with every lift, every long drive, every morning. Back pain that lasts more than three months is defined as chronic back pain, and at that stage it is already running your day: what you lift, how you sleep, whether you go out or stay home. If the pain is especially strong, read our guide to severe back pain as well.

A back that locks again and again, or will not release? That is exactly where pulsed electromagnetic fields come in.

What to Do for Acute Back Pain? PEMF — the Push Your Back Needs

PainFree’s pulsed electromagnetic fields bring you a focused treatment for the lower back that reaches deep into the tissue of the painful area — with no needles, no injections and no medication. The pulses bring the pain down — and the exercises keep the result.

If every movement in bed sends a stab into your back, and if the pain will not even let you start the exercises you were given — you are stuck in a painful cycle. It hurts, so you don’t move. You don’t move, so the muscles stiffen even more. And it hurts again. To break this cycle and get back to movement, your body needs a powerful technological push.

Why pulsed electromagnetic fields at PainFree?

• 🔬 Tested in low back pain: in a meta-analysis of 14 controlled trials with 618 patients, pulsed electromagnetic fields (PEMF) reduced low back pain more than a sham treatment, and the significant reduction was found in chronic pain (Clinical Rehabilitation, 2022; see the study on PubMed).
• 🎯 Focused on the source of the pain: the pulses reach deep into the muscles and tissues of the lower back and work on the whole locked area at once — with no painful contact and no pressure on a sensitive back.
• 🔓 The key to moving again: when the pain goes down, it is easier to move, walk and do the exercises that build a strong back.
• ❌ No needles, no injections and no pills: a pleasant, non-invasive treatment with no recovery time — you leave the clinic and get on with your day.
• 📍 A proven network: 70+ Israeli clinics serving a population of 9M — now expanding to the Philippines. Sessions in the Philippines: ₱1,500–₱2,500/session.

Stop suffering with every movement. Don’t wait for the spasm to become a pain that runs your week.

What Else Can You Do at Home in the First Days?

The pulses do the work in the clinic — and at home, between sessions, a few simple habits help the back release:

• Move gently: a short walk around the house or the building, several times a day. Movement keeps the muscles flexible and stops the back from “setting”.
• Local heat: a heating pad or a hot shower calms the locked muscles for many people.
• Painkillers — only as your doctor or pharmacist advises: follow the instructions and do not exceed them, in line with your own health situation.
• A comfortable sleeping position: on your side with a pillow between your knees, or on your back with a pillow under your knees.
• Back to the exercises: as soon as the pain allows, strengthening and posture exercises build a more resilient back and help prevent the next spasm.

What to avoid in the first days: heavy lifting, long sitting without breaks and sharp twisting movements. A complete, step-by-step guide to back recovery is waiting for you in our lower back pain treatment guide.

🔬 The Science Behind the Relief: Pulsed Electromagnetic Fields (PEMF) and Low Back Pain

Pulsed electromagnetic fields (PEMF) have been tested in low back pain in controlled trials, and the numbers speak for themselves:

• 14 trials, 618 patients: low back pain fell more with pulsed electromagnetic fields (PEMF) than with a sham treatment, and the clear effect was found in chronic back pain — pain lasting for months (meta-analysis, Clinical Rehabilitation, 2022; see the study on PubMed).
• 50 patients with chronic back pain: the group that received PEMF together with physiotherapy improved on the functional disability index by about 8 points more than the group that received the same physiotherapy with a sham device (randomised trial, 2019; see the study on PubMed).
• Safety: in a systematic review of 9 trials (420 patients), no serious adverse event was reported in any of the studies (2023; see the study on PubMed).

Further reading on pain that lasts a long time — chronic back pain treatment.

Comparison: What Helps Acute Back Pain, and What Each Option Gives You

Pulsed electromagnetic fields aim straight at the pain that will not release — and this is how they compare with the other options:

How Will You Feel the Pulses Working for You?

The pulses give you back your day — and you feel it in the small things:

• Your mornings change: you get out of bed without rolling onto your side and without looking for something to hold on to.
• Sitting comes back: you sit in the car, at work and in front of the TV for longer, without shifting every few minutes.
• Movement comes back: you bend to tie a shoelace, put on socks and lift a shopping bag without worrying.
• The exercises get easier: when the pain goes down, it is easier to do the exercises and keep at them. At the suitability assessment we write down together what is hard for you today, so you can see exactly what has come back.

When Does Back Pain Need a Doctor or the Emergency Room Right Away?

Most back spasms are not dangerous, but some signs require an immediate medical examination:

• Weakness in a leg, a leg that “drags”, or difficulty lifting the foot
• Numbness or loss of sensation in the groin, buttocks or genital area
• A new problem controlling urine or bowel movements
• Fever, chills or feeling generally unwell together with the back pain
• Severe night pain that does not change with movement or a change of position
• Pain that started after a fall, an accident or a blow
• A history of cancer, or unexplained weight loss
• Pain that radiates into both legs

In any of these situations — go to a doctor or the emergency room immediately. Pain that gets worse day by day, or shows no improvement at all after a few weeks, is also a reason to be checked by your family doctor or an orthopaedist. If the pain travels down from the back into the leg, read about the symptoms of a herniated disc as well.

Who Is the Treatment Not Suitable For?

Pulsed electromagnetic field (PEMF) treatment is not suitable when there is:

• A pacemaker, defibrillator or other active electronic implant
• Pregnancy
• Epilepsy
• An active malignant tumour

At the suitability assessment we go through your medical situation together, to make sure the treatment is right for you.

Frequently Asked Questions

How long does acute back pain (a back spasm) take to pass?

In most cases a back spasm eases gradually, within days to a few weeks, with the first days being the hardest. If the pain lasts beyond that — it is time for a suitability assessment: in a meta-analysis of 14 trials in low back pain, PEMF reduced pain more than a sham treatment, mainly in chronic pain (see the study on PubMed).

Heat or cold — which is better for acute back pain?

In the clinic, the pulses treat the deep pain in the lower back. At home, most people find that local heat — a heating pad or a hot shower — calms the locked muscles, and some prefer cold in the first hours. Choose whatever eases it for you, and do not put heat or cold directly on the skin for a long time.

Rest or move when your back locks up?

The pulses bring the pain down so you can get moving again — and that is exactly what the back needs. Short walks several times a day are better than lying down.

When should you see a doctor for back pain?

Immediately, if there is weakness in a leg, numbness in the groin, a problem controlling urine or bowel movements, fever, night pain that does not change with movement, pain after a fall or accident, or a history of cancer. And also if the pain is getting worse, or there is no improvement at all after a few weeks.

Does PEMF (pulsed electromagnetic fields) replace physiotherapy?

No — the pulses don’t come instead of physiotherapy; they are what lets you do it and keep at it. In a randomised trial in 50 patients with chronic low back pain, PEMF together with physiotherapy improved the functional disability index by about 8 points more than the same physiotherapy with a sham device (see the study on PubMed).

Does the pulse treatment hurt?

No. It is a non-invasive treatment, with no needles and no injections. In a systematic review of 9 trials in low back pain, no serious adverse event was reported in any of the studies (see the study on PubMed).

How many sessions are needed?

The pulses are given in a series tailored to you at the suitability assessment, according to your condition. In the trial in 50 patients with chronic low back pain, 12 sessions were given over 4 weeks (see the study on PubMed).

Start With a No-Obligation Suitability Assessment

Back locked up? Don’t wait for the pain to become part of your routine. Pulsed electromagnetic fields are waiting for you — an advanced, non-invasive treatment with no needles and no medication, so you can get back to getting up, sitting, driving and living without calculating every movement. PainFree runs in 70+ Israeli clinics serving a population of 9M — now expanding to the Philippines.