It's caused by working the muscle to fatigue and the muscle is trying to recover and the muscle knows that it has to grow to handle what your doing to it so if you keep lifting heavy you will be sore as the muscle keeps growing to handle the extra weight your constantly putting on it.
True.
Delayed onset muscle soreness
This article says that it isn't related to lactate acid buildup and suggests it might be caused by muscle tissue breakdown: http://www.sport-fitness-advisor.com/delayed-onset-muscle-soreness.html
delayed onset muscle soreness doctor of medicine
Massage therapy has been shown to be effective in reducing delayed onset muscle soreness by improving blood flow and reducing inflammation in the muscles.
The leading hypothesis for delayed onset muscle soreness are the: connective tissue damage hypothesis the skeletal muscle damage hypothesis the spasm hypothesis
Massage can be effective in reducing the symptoms of delayed onset muscle soreness (DOMS) by improving blood flow and reducing inflammation in the muscles, leading to faster recovery and decreased pain.
Delayed onset muscle soreness (DOMS) after intense physical activity is often caused by factors such as muscle damage, inflammation, and the buildup of waste products like lactic acid. Additionally, eccentric muscle contractions, inadequate warm-up, and insufficient recovery time can also contribute to DOMS.
DOMS stands for delayed onset muscle soreness, it is caused from working out muscles and them developing small tears causing the muscle to grow. The only way to treat it is to let it pass the soreness will go away when the muscle heal.
Muscle soreness can be caused by physical activity that the muscles are not used to, resulting in micro-damage to muscle fibers and inflammation. It can also be caused by muscle tension due to stress or poor posture. Dehydration and electrolyte imbalances can also contribute to muscle soreness.
Iain Douglas Hill has written: 'Delayed onset muscle soreness (DOMS)'
Usually it will go away in less than 24 hours.