In Part 1 we defined DOMS started to discuss the causes of DOMS.
DOMS is associated with electrolyte imbalances, an accumulation of white blood cells (immune system cells that respond to amongst other things muscle damage), and cytokines. Cytokines are communicators which stimulate the movement of cells toward the sites of inflammation, trauma, and infection. It is also associated with production of reactive oxygen species (ROS), resulting in further inflammation and oxidative stress.
Both blood work and MRI can show changes in the muscles indicating that damage has occurred. But neither is practical to perform, certainly not practical on a regular basis.
In a 2020 paper on DOMS, the authors propose another theory: damage to the muscle spindle and the nerves that supply it. Muscle spindles are stretch receptors within the body of a muscle that primarily detect changes in the length of the muscle. Interestingly, the authors propose a cognitive component or the awareness that you have gone “over the limit” and caused an energy deficiency which places you out of balance. These pathological changes in the muscles and nerves ultimately cause symptoms like muscle soreness, muscle stiffness, and pain.
Yes, this is complicated!!
So now that you know what DOMS is, how do we differentiate it from an “injury?” Or is DOMS an injury?
What is the definition of injury? The International Olympic Committee defines injury as “Injury is tissue damage or other derangement of normal physical function due to participation in sports, resulting from rapid or repetitive transfer of kinetic energy.” They then break it down into acute onset vs gradual onset and contact vs non-contact. Finally, there is the very important issue of time lost from training and/or competition.
You can think of it this way. Is the DOMS you are experiencing going to prevent you from training? Or might it be better to think, “is it really wise for me to train today based on how I feel?”
Here is a very telling comment by a coach:
“An athlete was very close to qualifying for the Olympics (…) and we kind of pushed a little bit and she had some soreness (…) She was not completely honest with me about how much she was hurt and I was also blinded by the goal. I didn’t quite take it as seriously as I should. And maybe, if we had a week off, she would have been in the Olympics. But she was not.”
Lot’s to think about and consider. More in Part 3.