A lower back sprain can happen suddenly or can develop slowly over time from repetitive movements.

Strains occur when a muscle is stretched too far and tears, damaging the muscle itself.

Sprains happen when over-stretching and tearing affect ligaments which connect the bones.

In most cases, it does not matter whether the muscle or ligament is damaged because the symptoms and treatment are the same. https://www.nhs.uk/conditions/sprains-and-strains/

Common causes of strains and sprains include:

  • lifting a heavy object or twisting the spine while lifting
  • sudden movements that place too much stress on the low back, such as a fall
  • poor posture over time
  • sports injuries, especially in sports that involve twisting or large forces in impact