(240) 530-8188

Why am I sore after exercise?

Posted on: July 26th, 2021 by Our Team

If you are a regular at the gym, or just started an exercise routine, it is common to experience muscle soreness following participation in strenuous activity. Soreness or discomfort after a strenuous or new strength event is very common.  Understanding muscle soreness as a natural outcome following physical activity, how to mitigate it, and what is normal all help drive a safer and more successful exercise program.

Normal post exercise pain not related to injury is muscle soreness, that can be attributed to the strain and mild damage to the sarcomere (contractile element of muscle tissue). This degeneration and breakdown of the sarcomere initiates the body’s inflammation response and is supported by the surrounding connective tissue. The inflammatory cells stimulate pain receptors which are associated with two stages of discomfort: Acute Muscle Soreness (AMS), or Delayed Onset Muscle Soreness (DOMS).

Acute Muscle Soreness

Acute Muscle Soreness, or AMS is pain felt in muscles immediately afterwards or up to 24 hours following exercise. The pain can occur within a minute of a muscle contracting, and usually dissipates within two to three minutes, or up to several hours after relaxing the targeted muscle group. There are two common causes of AMS, one being the build up the accumulation chemical end products of exercise lactic acid, and the other being muscle fatigue, where the muscle struggles to contract. When you work out, the body uses oxygen to break down glucose (sugar) for energy. During intense exercise, enough oxygen may not be readily available to complete the process, so a by product called lactate is made. The body can break down lactate without using oxygen, but this lactate, or lactic acid can build up in our blood stream faster than we burn it off.  Lactic acid and other waste product build up creating a shift in the PH in the muscle tissue.  The accumulation is associated with symptoms such as a burning sensation in the affected muscle group, cramps, and weakness.  These symptoms are very commonly benign and are safe when treated correctly.

Delayed Onset Muscle Soreness

The repair of the sarcomeres and surrounding connective tissue leads to delayed onset muscle soreness (DOMS) which occurs anywhere between 24 to 72 hours following physical activity. DOMS is believed to be caused by eccentric, or lengthening exercise of the muscle while it is under tension.  The stress of this mechanic causes small scale microtrauma to the muscle fibers. This microtrauma is a positive response and necessary event to hypertrophy and adaptation.  As a basic rule, the body adapts to both stresses applied and not applied to the body. This microtrauma and associated biomarkers are simple level indicators to the body that it was not effective in meeting the force demands of the tasks the individual requested from it.  The body recognizes its own short comings and then during the reparative stage it encourages hypertrophy of the tissue, and other bio-adaptations to improve its capabilities in future events.  There are of course thresholds to how extreme we should push the body, and how much damage it can safely handle, recover from, and adapt from.  DOMS at low levels is safe, at higher levels the muscle breakdown can result in negative health events such as rhabdomyolysis, tendonitis, moderate level muscle strains, and more! Delayed onset muscle soreness can be mitigated or prevented by gradually growing into an exercise program.

How to reduce soreness?

To help relieve muscle soreness, try take a global approach to your gym routine. Alternate target muscle groups during different days of the week and allow target muscle groups to rest while working out different parts of the body (leg day vs. chest day, for example). Additionally, gentle stretching, rest, as well as modalities such as ice and hot packs can help alleviate muscle soreness. The aches and pains should be minor and are indications that your body is adapting to the exercise regimen.  

In conclusion

While it is not possible to completely prevent muscle soreness after exercise, the best way to reduce the severity of symptoms is to build up slowly to any exercise routines. This cautious approach will allow the muscles time to adapt to the changes they are experiencing.

About John

John Kirscht Jr., originally from Southern Maryland, is a 2019 graduate of the CACHE Physical Therapist Assistant program through the College of Southern Maryland. John was excited to start his Physical Therapist Assistant (PTA) career with the Southern Maryland Physical Therapy Division of The Centers for Advanced Orthopaedics (CAO) the summer of 2019.

This topic is important to me because the topic covers an important aspect of therapy. By being able to relay this information to patients, it provides the patients education on expectations and natural outcomes following a physical therapy session. This allows for improved patient/therapist communication as based on the patients response to therapy, the clinician will be able to modify and/or progress as indicated.


The information contained in cfaortho.com, somdortho.com, or caoperformanceandtherapy.com is neither intended as rendering medical advice nor as a substitute for seeking professional medical assistance. No relationship between The Centers for Advanced Orthopaedics and its practitioners may be created through cfaortho.com, somdortho.com, or caoperformanceandtherapy.com.  Any individual with specific questions regarding his/her individual health or treatment options should contact The Centers for Advanced Orthopaedics and schedule an appointment with one of its practitioners.

End of content dots