Stiff or Sore Muscles - What’s Really Going On?

Muscle stiffness is the body's reaction to intense physical activity or unfamiliar movements [1]. It is generally associated with a sense of malaise, fatigue, muscle-hardening, and pain. In today’s article, we explore exactly what muscles are, what happens to the body when they stiffen, and how you can best treat the problem. 

If climbing stairs feels like hiking up a mountain or if your arms ache when you lift them to wash your hair, then you probably have exercise-induced muscle soreness. 

Muscle soreness can be very frustrating and restricting, which is why we would like to give you a quick overview on how you can deal with this issue. 

What are Muscles?

The skeletal muscles are the active musculoskeletal system and are involved in all movements of the body. The skeletal muscles’ tasks include:

  • Enabling active movement of the body through muscle contraction
  • Ensuring an upright posture
  • Relief of the passive musculoskeletal system, i.e. the bones and joints

The active and passive musculoskeletal systems are generally connected by tendons. When the muscles contract, the contraction allows the muscles to transmit their force to the bones via the tendons, resulting in movement [2].

What are Muscles Made of?

The skeletal muscles have a specific structure. A muscle consists of several muscle fiber bundles, which, as the name suggests, consist of many muscle fibers. These muscle fiber bundles are surrounded by fasciae, a connective tissue that gives the bundles their shape and separates them from one another [3].

The muscle fibers consist of sarcomeres, the smallest functional components of the muscle. Myosin and actin filaments are located in the sarcomeres. These small fibers move against each other during a contraction and thus ensure that the muscle shortens for a fraction of a second. This is the movement that enables all other movements in the body. This reaction is always triggered by an electrical stimulus, i.e. a signal that is sent from the central nervous system to the muscles [2], [3].

What Causes Muscle Pain?

The cause of muscle pain has been the subject of much debate in science. Two main hypotheses have emerged:

  • The first hypothesis is the so-called metabolic hypothesis. It assumes that over-stimulation of the muscles results in intermediate metabolic products such as lactic acid, CO2, phosphates or creatine [4]. However, it has not been adequately proven in studies that lactic acid is the culprit, which is why this explanation is being met with increasing skepticism [5]. Lactic acid or lactate is more likely to be responsible for the short-term fatigue pain that occurs during exercise, for example on the last 15-meter stretch of a 100-meter sprint. Another explanation as to why metabolic products are not responsible for sore muscles is the half-life of lactate - the time it takes the body to break lactate down. The body requires about 20 minutes to break down the lactate produced during strenuous activity yet much of muscle soreness usually only becomes noticeable one or two days after the exertion [6].
  • The second hypothesis states that sore muscles are caused by microtrauma, i.e. tiny injuries in the sarcomeres, the muscle cells. This is also called the microtrauma hypothesis. The muscle fibers suffer this trauma from excessive mechanical stress with high and mostly unfamiliar exertion. The term trauma in this context refers to the tiny cracks in the muscle fiber structures that have arisen as a result of the high intensity of the exercise.

Types of Muscle Stiffness

We need to distinguish between two kinds of muscle stiffness: pain during exercise, i.e. direct or acute muscle soreness, and delayed onset muscle soreness (DOMS).

Pain from fatigue is the body's direct reaction to exercise, not what you feel as muscles ache a few hours or days later. Lactate (lactic acid) forms as a result of the strain, which for a brief moment results in your muscles being over-acidified. This is the pain you feel when you are in the final meters of a 100-meter sprint. Your muscles harden, the pain runs through your buttocks and leg muscles - but after a few minutes you can no longer feel it and you can walk normally again.

Delayed onset muscle soreness refers to the sore muscles that you feel about 12 to 72 hours after your workout. This type of muscle soreness is caused by new, unfamiliar training stimuli - for example, when you increase the number of weights you bench-press, try new exercises, or extend your running distance. The sore muscles are often most intense three days after the training session. Symptoms of DOMS, which are triggered by the microtrauma within the muscles, are as follows [7], [4]:

  • Pain
  • Muscle stiffness
  • Swelling of affected muscles
  • Muscle fatigue
  • Short-term loss of muscle strength
Symptoms of delayed onset muscle soreness

When these tears in the muscle fibers are repaired by the body, what is known as super compensation can occur. Super compensation means that the repair not only prepares the muscles for the same load, but strengthens them so that they are prepared for even greater loads [8].

What Can I Do To Get Muscle Pain Relief?

Almost everyone has had sore muscles at some point, regardless of whether they exercise regularly or not. Sore muscles can even become a problem in everyday activities, for example during garden work. Let’s review how you can help your body overcome these sore muscles faster and better.

1. Antioxidants

While there is still a lot of research to be done on the topic, it is generally believed that foods rich in antioxidants can help manage muscle pain. Antioxidants bind and fight the harmful free radicals that are released by intense exercise. Due to this anti-inflammatory effect, antioxidants could have a positive effect on the muscle inflammation caused by exercise [9], [10], [11].

Foods containing antioxidants


Foods that contain a lot of antioxidants are [12], [13], [14], [15]:

  • Cherry juice
  • pineapples
  • ginger
  • Berries
  • Dark chocolate
  • Kale

In addition to these foods, the spice turmeric also has a particularly anti-inflammatory and regeneration-supporting effect and is said to relieve the pain of sore muscles [16].

You can read more about the health benefits and the importance of antioxidants on our health portal.

2. Omega-3 Fatty Acids

Omega-3 fatty acids can also help with the muscle regeneration process [17]. They also have an antioxidant effect [18]. Particularly reliable sources for the unsaturated omega-3 fatty acids include [19]:

  • Freshwater fish (e.g. salmon)
  • Linseed oil
  • Chia seeds
  • Walnuts
  • Fish oil and algae oil extracts

Unsaturated fatty acids serve other important purposes in the body and have a major impact on your health. You can find out more about omega-3 fatty acids on our health portal.

3. Amino Acids

Amino acids are the basic building blocks of proteins. The most important tasks of these proteins, and thus also of the amino acids, include ensuring the structure and mobility of the muscles. It is therefore important to provide your body with the right “tools” to help rebuild muscles [20].

Your need for essential amino acids increases when you do a lot of intense exercise, which is why you should make sure that you provide your body with the right protein sources - at the correct quality [21]. You can read about what essential and non-essential amino acids are and what you have to pay attention to if you want to prepare meals with good nutritional value in our detailed article on amino acids on our health portal.

Did you know? The tasty snack watermelon is a hydrating source of amino acids. It contains a lot of the amino acid L-citrulline, which studies have shown to decrease the amount of time it takes for people to recover from muscle stiffness [22], [23].

A term that is often associated with exercise and amino acids is branch-chained amino acids (BCAA), which refers to the three essential amino acids leucine, isoleucine and valine. They support muscle strength and endurance and counteract muscle atrophy [24], [25]. BCAA can be bought as a supplement, but they are also found in many foods, for example in:

  • Eggs
  • raw salmon
  • Walnuts
  • Rice
Foods containing Branch Chain Amino Acids

4. Fascia Roll

The fascia roll is a relatively new tool in the sports industry. Even though there is more research still to be done on the subject, it has already been determined that rolling out one’s muscles can relieve pain. Conveniently, there are a few side-benefits to the practice as well: Regular use of a fascia roll can improve your mobility and flexibility, and prevent muscle fatigue [26].

Fascia rolls are made of rigid foam and help to loosen the bonded fascia and break down collagen - and thus relieve pain [27]. By “massaging” your fascia with this firm roller, you can loosen adhesions - this happens because the rolling pushes lymph fluid through the fascia and thus loosens congestion, which allows nutrients to reach the muscles more easily [28].

What are Fascia?

Fascia are connective tissues that run like a network through the entire body. Among other things, they cover your organs, bones, joints, and muscles. They help your body transfer strength, give it stability, protect the internal organs, and transport nutrients. In addition to water, fascia mainly contain elastin and collagen. The former is responsible for elasticity and mobility, while collagen provides stability.

Excess collagen is produced in people who do not exercise enough or who experience excessive stress levels. It collects in the otherwise lattice-like structure of the collagen fibers, creating chaos, i.e. things get messy when a neat network of fibers gets tangled. The fasciae are stuck together and lose flexibility, which is reflected in a noticeable loss of mobility. In addition, the collagen chaos makes it more difficult to transport important nutrients that the muscles need for regeneration.

5. Stretching

Opinions in science are also divided on the subject of stretching. For example, a 2011 study found that post-exercise stretching had little to no effect on muscle soreness [29].

In another study a year later, scientists were able to show that static stretching can reduce muscle performance [30]. Static stretching is the process of stretching a muscle for a specified amount of time - without causing discomfort.

Instead, if you want to stretch, you should rely on dynamic stretching: Here, both the muscles are stretched and the passive musculoskeletal system, namely the joints, are stimulated and warmed up. Your heartbeat will increase slightly, your blood circulation will be stimulated and your mobility and flexibility will improve through dynamic stretching exercises.

How To Avoid Muscle Pain?

You can reduce the risk of sore muscles by increasing your training incrementally and carefully, and adjusting it slightly to your fitness level. Excessive jumps in performance in too short a time lead to an overload of the muscles and thus to sore muscles or DOMS [7].

However, if you really want to improve your exercise performance, it is unlikely that you will never experience muscle soreness. Incorporate extensive warm-ups, stretching exercises or an appropriate cool-down period into your training routines, ideally with a fascia roller. In this way you won’t be able to completely prevent DOMS, but you can reduce its intensity and duration [29].

Remember that a bit of sore muscles is a normal part of a good workout and may even give you some confirmation of the work you have done. However, if you suffer from severe pain for several days, you should try adapting your training more consciously to your fitness level.

So, in summary...

What is Muscle Soreness?

Sore muscles or delayed onset muscle soreness (DOMS) is a reaction by your muscles to microtrauma (tiny tears) in your muscle fibers. Muscle soreness usually occurs 12-72 hours after exercise. The pain that you feel during a strenuous training session is short-term fatigue in your muscles, which usually disappears after a few minutes.

What Can I Use to Treat Sore Muscles?

To cure your sore muscles or to support the regeneration of your body, you can consume antioxidant foods such as turmeric, berries, cherry juice, or kale. Amino acids and omega-3 fatty acids also have a positive effect on your sore muscles. Patience and relaxation are also crucial. Always give your body the necessary rest before the next training session.

Can One Prevent Muscle Pain?

You can't really avoid sore muscles if you want to improve your fitness level. A balanced diet as well as sufficient warm-up and cool-down sessions can reduce the intensity of the muscle pain you experience.


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