A strain is less serious than a sprain.
Strains occur when the muscles and ligaments around a joint are overworked or used incorrectly.
The fibers of the muscle or ligament are over-stretched but not broken. There is discomfort and swelling at the area of injury. When the fibers of a muscle or ligament tear, it is called a sprain. If you do not feel that your strain is getting better in a few days, you may have a sprain. If you have immediate pain and swelling or hear a snap with your injury, you may have a sprain, or even a broken bone.