Final answer:
Delayed onset muscle soreness (DOMS) is caused by tiny tears in muscle fibers from intense exercise, not by lactic acid buildup. This soreness indicates muscle healing and strengthening, but insufficient recovery or improper technique can cause overuse injuries.
Step-by-step explanation:
The symptoms of soreness that occur 24-48 hrs after a single bout of intensive exercise are commonly known as delayed onset muscle soreness (DOMS). DOMS is traditionally thought to be caused by the buildup of lactic acid, but this is a misconception as lactic acid disperses quickly and is unlikely to cause the soreness experienced days after exercise. Instead, DOMS is currently believed to result from tiny tears in muscle fibers that occur during intense exercise when muscles are worked harder than usual. The healing process of these microtears involves inflammation and pain but also leads to muscle strengthening over time. Furthermore, if resistance training is performed with an improper technique or excessive load, it can cause overuse injuries to muscles, tendons, or bones, contributing to soreness and the need for adequate recovery time between intense workouts to prevent such occurrences.