Delayed Onset Muscle Soreness (DOMS)
We've all felt it, those painful movements that appear a day or so after activity that you're not used to, the kind of pain that hurts to move and lasts a few days. That's called Delayed Onset Muscle Soreness (DOMS) and so far, medically speaking, no one really knows what it is.
There's a predictable timeline for the experience: muscle pain appears 1-2 days after activity, the intensity rises, plateaus, and falls within 2-3 days and then it's gone. So basically start to finish it takes about 5 days for you to feel normal again. One interesting thing to note is that the body will build a tolerance to the activity, so if you want to avoid DOMS one of the best remedies is to do the activity often.
There's been several theories over the years about what happens in the muscle to cause the pain. What they all have in common and what everyone seems to agree on is that there's damage to the muscle. In extreme cases it's known as Rhabdomyolysis, which is when the muscle is damaged to the point that proteins are now in the blood. This condition is potentially fatal as the proteins damage the kidneys; if severe enough the individual can experience kidney failure. There still remains the question of which part of the muscle is damaged and why the discomfort is delayed in the first place.
When a muscle grows larger and gets stronger, it doens't get more muscle fibres. An infant is born with all the muscle fibres that the adult will have. What happens is the diameter of each fiber increases. When a muscle gets stronger to make more powerful contractions, it's because each fibre is swelling with proteins that cause the contractions to occur.
Each muscle fibre is encased with a membrane comprised of a tissue called fascia. Bundles of fibres are wrapped in fascia, bundles of bundles are wrapped, and those groups are also wrapped with other groups, and so on until the final muscle is wrapped in one last sheath of fascia.
A 2009 study reported that they believe that the pain experienced in DOMS is coming from the fascia surrounding the muscle tissue, and not the previously thought of contractile tissue. This finding is logical. As a muscle adapts to an activity, it would grow in diameter and therefore require more fascial membrane to cover it.
As far as treatment goes, there is consistent mention of the use of massage therapy. The pain reduction is temporary, but so is DOMS. Massage therapy is often used to reduce the symptoms of DOMS while the body heals.
It is recommended to receive treatment as soon as possible, and 1 or 2 sessions per incidence of DOMS should be enough.