Why we get sore after exercise

Right now, I have DOMS. It’s not one of those strange diseases that seem to pop up so regularly these days. It’s actually delayed onset muscle soreness (DOMS) from my workout yesterday. I have it from head to toe, and in all the muscles that should be sore from training the human body’s fundamental movement patterns as aggressively as I did yesterday. 

I have my trainer to thank for that successful workout. I deem it successful partly because I have DOMS. While some persons may think I am quite crackers to revel in the painful torment of DOMS, I see it differently. It has been suggested that DOMS may be used as a general (although vague) measure of the effectiveness of workouts, and there is some research to justify its use in such a case. However, it must be used with caution.

The current theory is that DOMS is actually a result of muscle damage from a difficult or unfamiliar exercise. The exact mechanisms of how DOMS occurs remain unclear, but it seems to be the product of inflammation that occurs as a result of the muscle damage. A teacher once described it to me in these very simple terms which I still use with my patients today: When one does an exercise with increased weight, or an unfamiliar movement, the body is not accustomed to that stress and one’s muscles actually develop microscopic tears in response to the stress. When those muscles heal, they adapt to the stress and that is how we get stronger. 

The pain is a consequence of the muscle damage and resulting inflammation. That is why we are tender when our muscles are touched or squeezed. 

As a general rule, DOMS usually appears around 5-8 hours after the novel stress to the body, and peaks 48 hours after exercise. However, this is variable and the intensity of the DOMS can depend on the individual, the difficulty of the workout, the level of fitness of the individual and one’s genetics. 

Despite some theoretical justification for its use, coaches, trainers and athletes need to be careful when using DOMS to gauge the success of their workouts for a number of reasons. Firstly, there is no direct evidence linking DOMS to increases in muscle size and strength. There are just theories and they are not conclusive. 

In addition, severe DOMS, which may indicate significant exercise induced muscle damage (EIMD), can reduce the person’s ability to generate force by 50%. This means that the muscle’s capacity for executing a task is reduced. Quite frankly, when I have DOMS (although it is rarely severe), all I want to do it to lie in bed. My ability to be physically active is diminished, as my body screams for recovery time. 

In fact, severe DOMS can decrease an athlete’s motivation to train. This can also reduce adherence to exercise in those who do not enjoy the activity, but are doing it for health-related reasons. Trainers and coaches need to modify workouts and allow for enough rest to accommodate for DOMS, otherwise they risk injury and non-compliance. Workouts that may produce severe DOMS should be avoided before competition. Studies have shown that in severe cases of EIMD regeneration of muscle can take 3 or more weeks. An expert in the strength and conditioning field has stated, “high levels of soreness lasting for days should be regarded as detrimental to the athlete because it is an indicator that the body has exceeded its capacity to heal efficiently.” Quite frankly, severe DOMS should be avoided in general because it impedes progress.

So given that DOMS is a vague indicator of EIMD, and that EIMD facilitates increases in strength through adaptive responses of the muscle, there is some justification that DOMS may be used as a gross indicator of the effectiveness of a workout, if strength is the main goal. However, this must be done with great caution, given that there is a lot of theory and little hard evidence linking the two. There is also a lot of variability in each individual’s response to exercise as many may experience consistent soreness, while for others it is a rare occurrence. Caution must also be used, as excessive DOMS is detrimental to performance and to the individual’s health, so coaches and trainers must prescribe exercise of the appropriate intensity, given the person’s abilities. 

As a result, DOMS should not be used as a definitive measure of results, given its inherent limits in assessing workout quality. Rather, it should be a simple tool to be used in conjunction with the scientific expertise and experience of the exercise professional. 

Carla Rauseo, DPT, C.S.C.S. is a doctor of physical therapy and certified strength and conditioning specialist at Total Rehabilitation Centre Limited in San Juan.

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