Why Am I Sore After Exercise?

Have you ever felt sore and stiff after a long day of activity? Maybe with trying a new exercise?

That response, while uncomfortable, is perfectly normal and to be expected! That sore and stiff sensation in specific muscle groups, or all over, is known as Delayed Onset Muscle Soreness (or DOMS for short). DOMS is a very normal phenomena that is the result of an increase in increased or new load on contractile tissues in your body, muscles and tendons primarily.

The exact cause of DOMS is still unknown, however, the most accepted theory is that activity/exercise beyond your usual load (intensity) causes microtrauma to the contractile components of an individual muscle fiber, known as a myofibril. When the intensity of exercise is properly dosed this microtrauma will cause the muscle fibers to grow back stronger and more resilient than before. This is a vital and necessary process to regain strength and function.

This particular process is due to the overload principle, which states that greater than usual load is required for structures to undergo adaptation. In this regard to physical fitness and rehabilitation, this is achieved by performing exercises specifically targeting weak muscle groups, applying an overload to these muscles, and causing microtrauma. In response, these affected muscle fibers will regrow stronger, and in turn are able to tolerate greater loads, thus leading to greater strength.

As this microtrauma is a necessary component of gaining strength it is very common for patients to experience DOMS when starting a physical rehabilitation program. Usually this is felt the next day upon waking, but can sometimes occur later the same day. DOMS is most commonly felt only in specific muscle groups that were exerted. The discomfort will usually persist for 24-72 hours at a time, gradually fading in intensity over this period.

DOMS is usually mildly painful, and affected muscle groups will feel stiff with decreased strength and range of motion as well. While this is uncomfortable, this is normal as the body begins to mend itself and recover.

It is important to note that DOMS should not be severely painful or debilitating. If this is the case, that means the load was too intense and caused too much trauma to the muscle fibers. Reducing exercise intensity next session is vital to avoid overworking muscles or potentially causing other injuries.

DOMS is also not a sole indicator of a “good workout”. Just because you are not sore after exercising does not mean that it was wasted. Strength, endurance, and mobility gains can still be achieved without DOMS, especially one you have acclimated to the initial period of starting a rehabilitation or an exercise program.

While DOMS will resolve itself over a several day recovery period, there are several steps you can take to make the process more tolerable. First, stay active as you can. Our bodies are meant to move, and doing so produces the body’s natural joint lubrication as well as promoting healthy blood flow throughout the body. Performing motions similar to the exercises that caused DOMS can help as well. For example, if your legs are sore from walking too much the day before going for a short walk will help to mitigate the soreness and will facilitate your recovery. Just be sure to not push past the discomfort into serious pain! This will cause more harm than good. Getting adequate sleep and rest as needed is important as well.

While uncomfortable and definitely not fun, DOMS is a common and perfectly normal experience as your body becomes stronger and more resilient.