Active and Passive Immunity. Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response. Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen.
Lower back tightness can cause muscle twitching, pain and reduced range of motion. Lower back muscle tightness is the cause of a muscle spasm. This can be brought on by a strain, overuse or muscle weakness, according to BetterMedicine.com.
Ask The Yogi. Q: My back always rounds in forward bends. Is this a problem? A: A round back in forward bends can be the result of several different forces. Tight shoulders, âarmoredâ thoracic spine, weak lower back or abdominal wall and the most common causes of tight hips or hamstrings.