What is Delayed Onset Muscle Soreness (DOMS)? Traditional and new theories of DOMS and treatment ideas.

We’ve all been there. You try a new exercise or someone talks you into a heavy workout and you wake up the next morning and can barely stand up because your legs are so sore.  For years I thought I had a pretty good understanding of what caused delayed onset muscle soreness, but some recent research may cause me to rethink how I think about and treat DOMS.  

In this article, I want to discuss what DOMS is and the differences between the traditional line of thinking compared to this more recent nerve based explanation.  Finally, we discuss how this information may potentially change the way we approach and treat DOMS.  

Delayed Onset Muscle Soreness (DOMS) is the soreness that you get after a strenuous activity or exercise.  When we talk about DOMS, it is not the burn you get during the exercise but specifically that soreness that shows up 1-3 days after.  There are a couple of interesting things about workouts that make you super sore.  

1. DOMS is usually worse after a new exercise. 

Think about the last time you tried a new exercise.  It wrecks you a little bit right?  I remember the first time I tried GHD sit-ups.  It’s an ab exercise popularized by CrossFit, hard to explain so I am just going to attach a YouTube link here, but using a GHD machine you can get way back into extension to really challenge range of motion.  I couldn’t laugh for weeks my abs were so sore, and forget about coughing.   GHD sit ups may or may not be good for you but I promise they will make you sore.  Heck, there is even a case where Dana Linn Bailey, arguably one of the most popular  and consistent body builders of all time got rhabdo from GHD sit ups, and look she’s super fit! Read more here.  

Muscle Confusion??? I believe it was P90X who coined or at least popularized the term “muscle confusion.”  Love the buzz word but someone needs to explain to me how a muscle gets confused.  They don’t really make decisions.  They either contract or they don’t. The term is interesting though because there is this thing where new exercises can definitely wreck your day.  So what is it about a new exercise that makes DOMS worse. This new updated theory may help make some sense of the “new” exercise soreness. 

2. DOMS is usually worse after eccentric exercise. 

Eccentric exercise is where the muscle is lengthening while under tension.  Think of the lowering  or negative phase of the bicep curl.  At the top of the curl the bicep is contracted and is in its most shortened state. As you lower the weight the bicep is still contracting in order to keep the weight from falling against gravity to the floor,  but at the same time the muscle is getting longer.  This is commonly referred to as the negative portion of the movement.  Workouts that emphasize the negative or eccentric phase will definitely make you more sore. Think eccentric pull ups, downhill running, or wall balls. 

What is Delayed Onset Soreness? Traditional Theory. 

Traditionally, we have thought of DOMS as a result of the inflammation following the break down of muscle fibers during exercise.  We know that after exercise muscle fibers experience a level of micro trauma that seems to be worse after eccentric exercise.  There is an immediate pro-inflammatory effect as your body releases the necessary substances to repair the cells. The beauty of this is there is a subsequent anti-inflammatory cascade for a net reduction in inflammation.  For those of you who want a deeper explanation, consider this snippet from Margeritelis et al. 

“Although the eccentric exercise‐induced muscle microdamage acutely upregulates pro‐inflammatory/pro‐oxidant agents (e.g., increased IL‐6), chronically over a longer term, it down‐regulates pro‐inflammatory/pro‐oxidant agents and upregulates anti‐inflammatory/anti‐oxidant agents (e.g., increased IL‐10; [Paulsen et al. 2012]). It has been suggested that these beneficial effects of eccentric exercise are partially mediated by the muscle fiber microdamage induced by the stretch experienced during the application of the higher forces generated during eccentric actions (Nikolaidis et al. 2008; Paschalis et al. 2011; Theodorou et al. 2011; Panayiotou et al. 2013).” (Margeritelis 2015). 

This quote, is consistent with my personal understanding, and what I believe to be the general consensus of DOMS. 

Microdamage of the muscle fiber leads to inflammation, pain, and swelling related to DOMS.  Makes a lot of sense. 

But then there are some things that are a little fishy… why does new exercise get you compared to your routine exercise.  Does the muscle really get confused… Come on now....

Why do people with autoimmune and other inflammatory conditions really struggle with exercise and disproportionate soreness.  This is something I have come to really question in my time as a physical therapist.

Lastly, why doesn’t DOMS always respond to treatment as easily as other forms of pain.  You can research all kinds of treatment techniques for DOMS. There are techniques that I have seen work for many, many pain problems. Yet, when it comes to treating DOMS the research is pretty scattered.  There is nothing that is super rock solid.  

Traditionally, I have focused on enhancing the anti-inflammatory effects of exercise.  I like to use techniques to help mobilize inflammation, fluid, and lymphatic techniques.  Cupping and Hypervolt percussion massage have been my best techniques but there is certainly always room to improve.  

New Theories behind Delayed Onset Muscle Soreness. 

The research article that made me go…hmmm….

From Sonkodi et al.  full text here. 

“According to our hypothesis, delayed onset muscle soreness (DOMS) is an acute compression axonopathy of the nerve endings in the muscle spindle. It is caused by the superposition of compression when repetitive eccentric contractions are executed under cognitive demand.” Sonkodi 2020. 

So what does this mean. If this theory is true it would mean that inflammation and swelling of the the nerve endings within the muscle spindle are actually what generates the symptoms of muscle soreness. The authors go into detail about the nature of eccentric exercise the the fluid compression around the muscle spindle.  If you're interested in this stuff, I highly advise you to read this but it is beyond the scope of our purpose here.  They present evidence that the symptoms of DOMS can indeed exist without the presence of muscle damage. If that in fact is true, well then how can DOMS be all about muscle damage?   

This has several key implications in how we think about exercise and the treatment of DOMS. 

I know this is complicated, so let’s try to break this down a bit more.  I too had to read parts of this article multiple times just to wrap my head around it.  

What is a muscle spindle.  The muscle spindle is a stretch and proprioceptive mechanism within the muscle.  It sends information through associated nerves to the brain for sense of muscle length and position.  It has associated reflexes to help us from over stretching and potentially injuring a muscle.  Think of the stretch reflex  when your doctor taps your tendon below the knee cap. There is a quick stretch from the tap, the reflex reacts and your thigh muscle contracts to shorten the quadriceps muscle and reduce the threat of the stretch. Another example would be when you bend down to go to touch your toes and you feel tightness on the back of your thigh.   The muscle spindles in the hamstrings  are telling your brain "maybe you are going a little too far" and signals a contraction / or tightness in the hamstrings to keep you from pulling something.  

The authors propose that compression of these nerves within the spindle happen during eccentric exercise and that is part of what creates the feeling of soreness.. 

The authors are consistent to state this mechanism occurs  “under cognitive demand.”  This part intrigued me.  It is their belief that the sympathetic nervous system, think flight or flight, must be involved to override the feeling of compression and threat that is present with repetitive exercise. This is why the exercise must be either strenuous or new to trigger the fight or flight response to allow you to get there.   Super interesting!   

Implications to the treatment of DOMS. 

The authors Sonkodi et all suggest "closed gate" exercises for the treatment of DOMS.  Closed gate they present as concentric only exercise  would trigger the anti-inflammatory effects of exercise without compression of the nerves within the muscle spindle found in the lengthening portion of eccentrics.  This idea of concentric exercise for recovery days is not new to strength and conditioning.  The recommendations of sled pushes or pulls or cycling are commonly used to activate muscle soreness in a primary concentric pattern on de-load days in programming.  The authors recommended swimming as their primary exercise choice based on mouse research.  This is something I want  to look more into.  

Are there ways to maximize the benefits of both eccentric and concentric exercises while minimize the negative effects?  

What about manual therapies ? The authors of this article do not discuss the use of manual therapies or other treatment techniques but my brain immediately goes there.   How might we alter our delivery of manual therapy to better effect sensory, compression, and fluid dynamics at the level of the muscle spindle.  If this theory holds true perhaps manual therapy treatments should have a slightly different tact when treating muscle soreness.  

Treatment techniques that come to mind include dry needling with electrical nerve stimulation that would target deep nerve sensory levels, targeted vibration and percussion massage times and frequencies that may have a greater effect on these sensory nerves. All of these are things that require further evaluation on my behalf but initially offer great potential.  

Future thoughts and considerations.  

In addition to the above, the authors cite evidence of changes to the blood brain and spinal cord barriers, as well as increased  permeability of the capsule of the muscle spindle.  They also, discuss the oxidative stress response.  These things have implications on aging and health at many levels.  If we could have a greater understanding of the values and physiological responses to both concentric and eccentric exercise this may help maximize exercise prescription towards targeted goals of muscle mass, bone health, and non-pharmacological pain relief.  

 I also can't help but to think about the role of the sympathetic nervous system in all of this.  If the sympathetic nervous system (SNS) is what enables the override mechanism to generate muscle soreness what effect does resting state have? Do people in some level of pain, say, post surgery or injury have higher levels of exercise soreness secondary to SNS activity.  Do people in high stress lifestyles, living in fight or flight mode, experience higher levels of muscle soreness.  Would something like meditation, deep breathing or other parasympathetic dominant activity help with DOMS?  At this stage these are all just interesting thoughts. 

Like most things in life, the more you know, the more you realize you don’t know anything.   This article certainly triggered that response for me and I look forward to exploring the exercise and age related responses to not only DOMS but other exercise prescriptive health and performance benefits.  

Written By: 

Dr. Nicholas Sanders PT, DPT, CSCS, CIDN.

Nick is the founder of PHYT For Function a one on one specialty, physical therapy clinic in North East Ohio and Co-Creator of the Neuro-Release Treatment Course, a nervous system based cupping, percussion massage, and IASTM manual therapy course presented by Integrative Dry Needling.  Nick is both a doctor of physical therapy and certified strength and conditioning specialist. He is driven to find the best combination of manual therapy, exercise, and lifestyle habits to improve pain, stress, aging, and performance. 

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