Quick version
What is lower back pain?
The lower back is the lower part of the spine and is often a vulnerable area during strength training. When the back is exposed to high forces, such as during squats, deadlifts, and pressing exercises, pain can arise from the muscles, joints, discs, or nerves of the spine.
Why does the lower back hurt after exercise?
It is common to experience lower back pain after heavy or unfamiliar loading. The pain can have several causes and presents differently depending on which structure is affected. A muscle strain or spasm often causes sudden, localized pain that worsens with movement. In cases of disc involvement, the pain may radiate down the leg and sometimes cause numbness.
Overloading of the facet joints in the spine often leads to stiffness and a dull, aching pain that becomes more noticeable during backward bending, while problems related to the SI joints usually cause pain low on one side of the back, sometimes radiating toward the buttock. Understanding the cause of the pain is important in order to choose the right treatment and adapt your training.
Can heavy loading cause a herniated disc?
Yes. Between the vertebrae of the spine are discs that act as shock absorbers. With repeated heavy loading, especially when combined with a flexed or rotated spine, the outer layer of the disc can rupture. This is called a herniated disc and means that the disc begins to bulge outward and may irritate nearby nerve roots, thereby causing pain.
Herniated discs often occur during heavy lifting with poor technique, rapid increases in weight or training frequency, or when training despite fatigue or existing pain.
Is rest enough?
If you have mild to moderate pain without signs of nerve involvement, it is usually sufficient to take a short break from heavy training while continuing to stay active, as complete bed rest can worsen back pain. Modify movements and use pain relief if needed. Gradually return to heavier training with a strong focus on proper technique. Most people become pain-free within 1–3 weeks.
How do I know if the pain is caused by a serious condition?
In most cases, back pain after exercise is harmless and resolves with rest and adapted training. However, there are certain symptoms that may indicate more serious conditions and should be taken seriously. If the pain does not improve or decrease after a few days, worsens despite rest, or significantly limits your mobility, it may be a sign of a more serious injury.
Be especially alert if the pain radiates down the leg or if you experience numbness, tingling, or muscle weakness. If the pain worsens when coughing or sneezing, if you develop severe pain after a specific movement, or have difficulty standing or walking, the nerves may be affected. If you experience these symptoms, you should contact healthcare services for assessment.
How can an MRI of the spine help?
If a more serious condition is suspected, an MRI (magnetic resonance imaging) of the lumbar spine can be helpful. MRI is primarily recommended if the pain does not resolve despite adapted treatment or if nerve involvement is suspected. The examination can show whether there is a herniated disc, nerve root compression, inflammation, or other structural changes that may explain the pain.
When should I seek medical care?
Contact healthcare services if the pain does not improve after 2–4 weeks, if you experience symptoms of nerve involvement, or if the pain is very intense immediately after the injury. Seek emergency care if you have difficulty controlling your bladder or bowels or if you experience severe numbness in the genital area.
Treatment and rehabilitation
Treatment should be tailored to the underlying cause but often includes physiotherapy with gradually increasing load, pain-relieving medications, and personalized exercise programs to improve core stability and mobility. Surgery is usually not required but may be considered, mainly in cases of significant nerve involvement.
Preventive advice for those who train:
- Focus on proper technique, especially during lifting
- Increase load gradually
- Vary training methods and allow time for recovery
- Stop training if you experience pain