Maybe yesterday you went out to run up and down that mountain you have always wanted to. Or you just had an excessively intense strength workout. Or you tried to beat your friends doing as many push-ups as you could. Whatever you did, today you can barely walk. Or raise your arms. You even struggled getting out of bed. But don’t worry, it will get better soon. It is just a case of DOMS.
You have probably been victim of the painful muscle soreness after taking up any physical activity that you weren’t used to. Or after changing your training program or excessively increase the load of the workout.
But, have you ever wondered what is it that causes such pain? Well, you are facing what is called delayed-onset muscle soreness (DOMS) and here we will discuss everything you need to know about it, from what it is, to how to prevent it!
What is it?
DOMS is the sensation of discomfort or pain within the skeletal muscle post-exercise. Anyone who has ever exercised recognizes that muscle weakness and sensitivity after overdoing it.
There are numerous characteristics of DOMS beyond local pain. Some of the most common symptoms include:
- Tenderness to the touch.
- Stiffness and reduced range of motion in the joints.
- Swelling in the affected muscles.
- Muscle fatigue and weakness.
As its own name says, and according to the American College of Sports Medicine, the delayed-onset muscle soreness begins to develop 12 to 24 hours post-exercise and may reach the peak at 24-72 hours. Although it may be certainly painful in some cases, it disappears 5-7 days post-exercise. We should not mix up DOMS with acute muscle soreness, which refers to the pain felt during and immediately after exercise.
What triggers DOMS?
Engaging in any type of activity that places unaccustomed loads on muscles may lead to DOMS by causing micro-tears in them. Therefore, even a high-level cyclist, in incredibly good shape, will likely get delayed-onset muscle soreness the first time he goes for a run, despite the load of the exercise bout is way smaller than that he is used to. One will also get DOMS if workload is suddenly increased over his muscle’s capabilities, which places excessive stress on them, resulting in cellular damage.
However, eccentric contraction – lengthening of the muscle while it contracts – causes it far more readily than concentric contractions.
Why is that? Well, during eccentric exercise, large forces are distributed over a smaller cross-sectional area of the muscle compared to concentric actions. This places way more stress on each muscle fiber, which results in a greater subcellular disruption. Smith explains that this is due to the fact that “fewer motor-units are activated during an eccentric, compared to a concentric action for a comparable amount of work”.
Fewer motor-units are activated during an eccentric, compared to a concentric action for a comparable amount of work.Smith 1992
Paradoxically, despite being of such a relevance within the sports field – just remember, it is one of the sectors that more money makes annually and where every single detail accounting for the athlete’s performance is thoroughly optimized – little do we know about the underlying biochemical events that lead to delayed-onset muscle soreness.
From my point of view, understanding the biochemical mechanisms underlying DOMS would be of great help within the exercise science field since it would help developing more efficient treatments as well as prevention strategies and ensure a better continuity of training, which would potentially further optimize athletic performance.
Anyway, let’s get deep into this! Even though several theories have been proposed to explain this phenomenon, the general consensus among researchers is that a single theory is unable to explain it. Instead, researches have proposed a series of events as an attempt to find an explanation to it:
- High tension placed on the muscle fibers during exercise results in structural damage to the muscle and its cell membrane. Connective tissue is also damaged.
- Damage in the cell membrane impairs calcium homeostasis, which results in an increased intracellular calcium concentration. In turn, high levels of calcium inhibit cellular respiration and activates enzymes that degrade the Z-lines of the sarcomeres.
- During the first few hours after the onset of injury, neutrophils – which participate in the inflammatory response – are attracted to the injury site.
- Macrophages then accumulate around the injury site about 6 to 12 hours post-exercise.
- Prostaglandins produced by macrophages sensitises type III and type IV nerve endings (“pain nerves”) to mechanical, chemical, and thermal stimulation.
- Accumulation of histamine, kinins, and K+ from macrophage activity and intracellular contents together with elevated pressure from oedema and increased local temperature may then activate nociceptors around the injured area.
Despite this sequence of events has been proposed, it still remains hypothetical and further research is required.
How can it be prevented?
Delayed-onset muscle soreness may interrupt your workout continuity, and therefore hinder your performance improvement. But I have some bad news for you… DOMS cannot be prevented if you want to get fitter. Body adaptations to exercise that allow for enhancement in performance require unaccustomed loads that cause microscopic damage in muscle tissue, ultimately causing muscle soreness.
However, you can – and you should – reduce its severity so that its “side-effects” don’t have much impact on your training program. And the best way to do this is to progress slowly into a new program. Take the principle of progression seriously. When you take up a new activity, gradually increase the intensity and duration. Place special attention on eccentric actions and gradually increase its intensity and duration. Take it slowly and don’t go too fast, or it will ultimately make you fall behind.
I would like to point out that warming up, cooling down, and stretching don’t really have much scientific evidence as preventive strategies for DOMS. However, they may prevent more serious injuries.
How can it be treated?
Unfortunately, there is no way to hasten the recovery process of DOMS. However, there are several treatments that ease the symptoms, despite having no effect on the healing process of the muscle. Strategies for reducing pain include:
- Ice pack application.
- Tender-point acupressure.
- Oral pain relief.
- Low-intensity exercise.
Can I continue exercising with DOMS?
Yes, you can. Light exercise may even reduce the pain temporarily, although it feels uncomfortable at the beginning. However, you should listen to your body, and if the pain is too intense, you may need some days of rest.
Obviously, high-intensity exercise should not be resumed until no more pain is felt, especially movements that caused the DOMS you are suffering from.
Delayed-onset muscle soreness is a familiar experience – muscle discomfort or pain, weakness, and stiffens among other sensations – we all get several hours after engaging in a physical activity that puts unaccustomed loads on the muscles. If the load placed on the muscles exceeds their capability to support it, excessive stress within the muscle fiber causes microscopic damage. This is especially common in eccentric contractions, since large forces must be supported with a smaller cross-sectional area of muscle fibers compared to concentric contractions.
The mechanisms behind this phenomenon are still in debate, although it seems that muscle damage and the subsequent inflammatory response are the most accepted explanations for it.
Although DOMS cannot be prevented, its severity can be effectively reduced by introducing the new activity or programme progressively and gradually increase the load. Once set in, treatment strategies to reduce the pain include cold therapy, oral pain relief, and light exercise among others. However, pain reduction does not represent recovery. These strategies may be effective in reducing symptoms of pain, but underlying muscle damage and reduced function may persist.
So you now know that slower is sometimes faster!
- Cheung, Karoline, Patria A Hume, and Linda Maxwell. 2003. “Delayed Onset Muscle Soreness Treatment Strategies and Performance Factors.” Sports Medicine 33 (2): 145–64.
- Smith, Lucille L. 1992. “Causes of Delayed Onset Muscle Soreness and the Impact on Athletic Performance: A Review.” Journal of Applied Sport Science Research 6 (3): 135–41.