We’ve all been there – you ran a race, lifted heavy at the gym, or added extra miles to your ride – regardless, you worked hard and are now paying for it dearly the day after. You have what’s known as Delayed Onset Muscle Soreness, or DOMS. DOMS can vary in it’s appearance, sometimes starting up anywhere from roughly 12 to 72 hours after a particularly intense bout of exercise.

DOMS is essentially muscle soreness that seems to develop long after you’ve completed a workout. The later it shows up is certainly confounding to many who’ve experienced this.

Sure, the workout was tough and you felt it, but once you’ve rested and recovered suddenly you become sore - really sore. Perhaps the best example of this is the day after a Marathon – your legs seem wrecked!

It can happen to anyone, no matter what kind of shape they’re in. Any athlete can attest to this, as DOMS is almost certain to appear after a change in duration or intensity, when the muscles are otherwise unaccustomed to new stresses.

Why do we get DOMS?

An older theory of DOMS was that it’s caused by a build up of lactic acid and other ‘waste’ products. In fact, you still probably hear people spout this off here and there! This has been disproven time and time again. Lactic acid is considered a fuel and is gobbled up by exercising muscles – none of it will be found sitting around in your muscles the day after a workout.

DOMS is really due to microscopic damage, or “microtrauma” in the muscles This breakdown of the muscles is normal and plays an important role in adaptation to gains in strength. However when we experience DOMS this is a signal we’ve overdone it and now the muscles are inflamed.

Even stress-adapted muscles are still broken down to some extent when pushed beyond the normal training boundaries.

DOMS most often occurs during eccentric muscle movements, or when force is applied to a muscle that’s lengthening. The best way to think of this is what happens to your thighs as you run down a hill – the quadriceps extend until they are met with the force of the foot hitting the ground.

Symptoms of DOMS

The pain of DOMS is different from that you might encounter during exercise. It’s marked by exquisite tenderness of the muscles – they even hurt to touch! Other common symptoms include:

• Limited range of motion
• Joint tenderness
• Loss of strength
• Minimal swelling of the affected muscles.

More serious signs include very swollen muscles or dark urine, despite hydration. If this happens, you need to see a doctor. In extreme cases, excess muscle damage can lead to a condition known as rhabdomyolysis. This occurs when muscle breakdown is excessive and uncontrolled. Rhabdomyolysis occurs when the muscles release large amounts of the enzymes myoglobin and creatine kinase, which can quickly overwhelm the kidney’s ability to function normally.

It may seem like DOMS is an unavoidable consequence of intense training – that isn’t necessarily true. In the future we’ll address how you can better prepare your muscles for the stress of training so you’re less prone to DOMS, and how you can ease the pain if you do develop it.  Stay tuned!