15 February 2021

You know that feeling the day after a really hard work-out, or the feeling you get after finishing your first big gym session after weeks or months off? The feeling when you wake up in the morning, your body is tense and crampy, every movement takes a lot more effort, and it feels like you are on fire? That feeling is known as delayed onset muscle soreness (or DOMS for short), and it can often be the root cause when a new client discontinues a program due to extreme pain, or dislike of a style of training.

DOMS is a form of muscle soreness, weakness or cramping that is prevalent between 24 and 72 hours after a heavy workout. DOMS usually occurs when you first start training or try a new intensity or form of exercise that your body is not used to (Cheung, Hume & Maxwell, 2003). It can also be referred to as ‘muscle fever’ ( and can range in severity, from mild tenderness of your working muscles to severe pain. In extreme cases, DOMS can even lead to rhabdomyolysis (rhabdo for short). Rhabdo - which can be very dangerous - occurs when extreme levels of myoglobin in the blood, caused by too much breakdown of a muscle or ruptured muscle fibres, leads to a metabolic poisoning of the kidneys.


DOMS can continue for up to 72 hours after a workout, and its impact can vary based on an individual’s training experience and pain thresholds. Factors and activities that can increase your risk of developing muscle soreness post-training can include:

  • A return to training, with higher volumes or intensities than you are used to;
  • A change in training, where muscles are targeted in a different way;
  • Increased intensity, or overall changes in physical stress that do not fall within your usual range (Pain science & Cheung et al., 2003).

The mechanism for why DOMS occurs is largely unknown. There are many theories and ideas, but little evidence to prove or disprove them. Some researchers believe that it could be a combination of a few theories. For example, some researchers believe DOMS could be caused by a response to lactic acid or other byproducts being built up by working muscles; by muscle spasms, or damage or inflammation to muscle or connective tissue; or by an enzyme efflux theory. It may also be related to genetics (i.e., the different sensitivity between individuals and their response to a stimulus), eccentric muscle actions (i.e., the controlled descent and elongation of muscles causing microtrauma to the muscle fibres), or could be enhanced by other stress factors and made worse by dehydration or metabolic stress (Pain science).


It is also theorised that DOMS is aggravated by health issues such as acute fatigue, not recovering from a workout, or a lack of iron or vitamin D (the sunshine vitamin) - all of which can exacerbate fatigue from high-intensity or volume training that your body has not adapted to.

It has been noted that eccentric exercises can cause a greater frequency of microtrauma to a working muscle than other muscle action types (concentric and isometric) and therefore might help to explain muscle soreness and DOMS. Eccentric muscle contractions are caused by the lengthening of muscle fibres under tension, and can result in higher loads moved (compared to an isometric or concentric contraction). This can result in a larger change in the structure and connective tissues, and therefore more microtrauma to the muscle fibres. Eccentric muscle contractions have high levels of force generated; however as this is distributed over a smaller cross-sectional area of muscle, it results in increased tension per unit (

The direct cause of DOMS is still widely unknown, even with decades of research behind it! Whatever the reason for this delay in muscle soreness following intense or new exercise, we know that it definitely occurs, and can impact upon recovery for the next training session.


The physical impact of DOMS can negatively affect training and athletic performance; so athletes who are set to compete, or are on track for a big performance or game, are recommended not to alter their training intensity or try new exercises. Instead, they should taper, and control recovery. This is because DOMS can reduce a joint’s range of motion, influence muscle recruitment patterns and sequencing, and place new stress on different muscle groups, ligaments, or tendons in 24 to 72 hours post-workout.


There are two overall strategies to manage or reduce the effect of DOMS:

  • Reduce training intensity or duration to a level that the body can sustain and recover from, and/or;
  • Alternate exercises targeting different body parts and introduce eccentric exercises over a 1-2 week period, to allow for adaptation to a new training stimulus to occur at a sustainable rate.

Depending on an individual’s response and pain thresholds, DOMS can be a great indicator of progression and training stimulus - as long as you are finding the ability to push through and recover well. Over a few weeks, as the body gets used to a new style of training, the body will adapt and the pain response will be reduced. This is a positive sign that your muscles are recovering to a point where you can withstand a higher intensity or volume of training, and you are therefore showing an increase in performance and fitness.


DOMS treatment strategies can range in effectiveness and again, vary person to person. These can include the use of:

  • Non-steroidal anti-inflammatory drugs (NSAIDs) (ibuprofen) and COX-2 inhibitors (neural changes),
  • Massage or vibration,
  • Ultrasound or cryotherapy.
  • Massage or stretching,
  • Light training and movement.


These strategies have demonstrated varying results in research, with a small ability to help alleviate the symptoms and pain associated with DOMS, depending on the context and the individual. NSAIDs (like ibuprofen) have been used to alleviate pain, but symptoms often return once the NSAID has worn off. Research suggests that strategies such as stretching and massage can actually have no effect or, even worse, a detrimental effect on body feel and pain as muscle soreness can be made worse through strong massage.


We all learn through experience, and we know too well the DOMS that happens when we push too hard and cannot recover. It is great to be able to start to understand why this occurs.

As an exercise professional working with new clients, you must be aware that when you’re training someone with limited experience or changing a client’s routine, there will be a period of transition and change where DOMS may be prevalent. It is important to know how to recommend maximised recovery through sleep and hydration, as well as increasing a new exercise at a moderate rate to allow your client to adapt and progress comfortably. If you push too hard and your client is sore for 3 or 4 days and cannot train, you might send them running (or crawling) for the hills - especially if they believe that training will always be painful and no fun!

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-        Cheung, K., Hume, P. & Maxwell, L. (2003). Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors. Sports Medicine, 33, 145-164.