The Real Cause of Delayed Onset Muscle Soreness (DOMS) and How to Manage It

What Is DOMS?

Delayed Onset Muscle Soreness (DOMS) refers to muscle soreness that appears 24-72 hours after unfamiliar or high-intensity exercise. Key characteristics include:

• Soreness begins the next day or the day after, not immediately
• Most commonly occurs after downhill running, heavy eccentric movements, or new training exercises
• Presents as soreness, stiffness, mild swelling, and increased sensitivity to pressure
• Typically resolves naturally within 3-7 days

Debunking the Myth: DOMS Is Not Caused by Lactic Acid

“Soreness is caused by lactic acid buildup” is one of the most widespread misconceptions in sports.

The fact: Lactic acid is fully cleared from the body within 1-2 hours after exercise, so it cannot explain soreness that appears 24-72 hours later. The immediate “burning sensation” during exercise is indeed related to lactate and hydrogen ions, but that is not DOMS.

The Real Causes of DOMS

Current research points to the following mechanisms:

1. Microdamage from Eccentric Contractions

DOMS is primarily caused by eccentric contractions (muscle contracting while lengthening), such as:

• The quadriceps braking action during downhill running
• Lowering a heavy weight (muscle working while elongating)
• Thigh muscles during long descents on a bike

Eccentric contractions generate high localized tension within muscle fibers, causing microscopic structural damage — particularly disruption of the Z-lines (the boundary structures of sarcomeres).

2. Inflammatory Response

Microdamage triggers a local inflammatory response:

• 24-48 hours: Neutrophils infiltrate the tissue to clear damaged material
• 48-72 hours: Macrophages take over, releasing pain-inducing substances such as prostaglandin E2 and bradykinin
• These substances lower the threshold of nociceptors, making the muscle more sensitive to pressure

3. Edema and Pressure

Inflammation causes local swelling, which increases intramuscular pressure — another source of the pain sensation.

What DOMS Means for Training

Is DOMS a Sign That Training Was Effective?

Partially true, but it needs careful interpretation.

• DOMS is almost unavoidable the first time you perform a movement, or when resuming training after a long break
• As training becomes regular and the body adapts, DOMS gradually diminishes — even at the same training intensity
• “No soreness means the workout was ineffective” is a misconception — athletes who train consistently may show little or no DOMS even after highly effective sessions

How DOMS Affects Subsequent Training

The Protective Effect of DOMS (Repeated Bout Effect)

An important physiological phenomenon: when the same workout is repeated a week later, DOMS is markedly reduced (typically by 50-75%) — this is known as the “Repeated Bout Effect” (RBE). This protective effect can last 6-8 weeks, after which a new training stimulus is needed to maintain it.

Mechanism: After the first bout, the Z-lines of the sarcomere are reinforced, connective proteins within muscle fibers increase, and neuromuscular control improves, so that the same movement causes less damage when repeated.

Effective Ways to Relieve DOMS

Methods Backed by Science

Methods with Limited or Uncertain Effectiveness

Important Warning: Rhabdomyolysis

If any of the following symptoms appear after extremely high-intensity exercise, seek medical attention immediately — this may indicate dangerous rhabdomyolysis:

• Tea-colored or cola-colored urine
• Severe muscle swelling and weakness
• Muscle pain so severe you cannot walk
• Nausea, vomiting, fever

Rhabdomyolysis can lead to kidney failure and carries a significant mortality risk; it requires medical intervention such as intravenous fluids.

How to Prevent Excessive DOMS

1. Progressive overload: Any new training movement should start at low volume and low intensity
2. Avoid training to failure the first time you try a movement (especially eccentric-heavy training)
3. Maintain consistent training before races: Suddenly resuming high-intensity training after a long break is the main trigger for DOMS
4. Warm up thoroughly: While warming up cannot fully prevent DOMS, it helps prepare the muscles

Conclusion

DOMS is a normal adaptive response of the body to training stimulus. There’s no need to fear it excessively, nor should it be treated as the sole indicator of whether training was effective. Once you understand its causes, the most important recovery strategies are: adequate sleep, moderate active recovery, and massage or cold therapy targeted at the most affected areas. Most importantly, let your body grow stronger through recovery — don’t force high-intensity training through the soreness.

Related Reading

• Managing Post-Run Muscle Soreness: The Causes of DOMS and How to Speed Up Recovery
• Muscle Damage and Repair After Running: A Scientific Breakdown of DOMS
• The Science of Post-Run Muscle Recovery: The Mechanism Behind DOMS
• The Complete Guide to Preventing and Managing Running-Related DOMS