What Causes Muscles to Become Sore?
Every now and then, you might wake up to an unusual amount of muscle soreness and wonder why it became so instense, especially because the last time you worked out was a day or more ago. This kind of muscular pain, while good for you in the long run, can hurt quite a bit in the short term; it is also referred to as Delayed Onset Muscle Soreness or DOMS for short.
Does experiencing DOMS mean that you're out of shape? No, not necessarily. In fact, I am on the tail end of a DOMS episode after participating in an Army P.T. Test on Friday, 13AUG2010 (today, it is Sunday 15AUG). Despite performing quite well and netting a 277 out of 300 maximum possible points, I am still very sore from the pushups and situps exercises in particular. In my case, I felt the onset of DOMS at around 2PM or 3PM (roughly 9 hours after the completion of the test).
DOMS occurs when you do an activity that you have not been doing for quite some time. I spent most of my summer running, very little doing pushups, and absolutely none doing situps, so it makes sense that I would be most sore in those muscular regions. Also, the small amount of soreness I did experience in my legs from running quickly went away the next morning; this was not true of the rest of the DOMS.
On the cellular level, DOMS is the soreness that occurs from the muscle cells tearing (which happens when you work out). It most often happens when you do something that you haven't done in a while, but it is a result of physical effort, not of injury. The sensation of pain is very different from a muscular pull. When you pull a muscle, the pain comes sharply and instantly, but DOMS starts as a dull ache and can be felt as a deep rather than sharp pain sensation.Working out does not always produce DOMS, but it is much more likely to do so if you work out with weights or do high intensity exercises. It usually occus from increasing training intensity to a new level or performing a new exercise. Perhaps the worst case of DOMS I ever had was when I did lunges in high school for the first time; I could barely walk in the morning when I woke up.
DOMS typically comes while you sleep and goes away more gradually than it comes, but its appearance is actually a good sign. It typically means that you pushed yourself and your exercise is paying off! You should take it a bit easier until the soreness wears off, though. This makes it easier for your muscles to repair and allows you to keep improving.