muscle soreness

What Causes Muscle Soreness From Working Out?

Everyone has experienced muscle soreness from working out at least once in their life.

Excess muscle soreness can compromise your recovery. But how is muscle soreness from working out caused?

Are you ready? Scroll down!

What is Muscle Soreness?

Muscle Soreness, also called DOMS (Delayed Onset Muscle Soreness) is the sensation of muscular discomfort and pain during active contractions that occurs 24–48 h after strenuous exercise (source).

During exercise, you compromise your body and muscle fibres. To that "stressful" situation, your body responds adapting to the stiuation.


Muscle soreness from working out peaks after 48-72h, and usually goes away without intervention after 5-7 days.

Intensity of the exercise usually correlates to the extent of muscle soreness, although there are more factors to consider (study)

Muscle Soreness From Working Out Affects Your Recovery

Muscle soreness is a signal of muscle damage. It's the consequence of microscopic tears in the muscle or breakdown of muscle tissue.

The mechanisms causing muscle soreness are still quite unknown, and there are over six different theories trying to explain why that happens (study)


But one thing is clear. If muscle soreness from working out affects the recovery process.

It decreases your range of motion and isometric torque (study). And that translates into worse performance.

Muscle sorenes from workout shouldn't be avoided. But if too much, it can affect your following workout.

Muscle Soreness from working out

What Causes Muscle Soreness

The mechanisms underlying muscle soreness from working our are still quite unknown.

The hypothesized theories point in two different directions. Some claim DOMS to be related to excess muscle damage and breakdown of connective tissue.

Others relate muscle soreness to the inflammation and accumulation of oxidative stress after exercise. But what theory is the good one?

that-s an excellent question meme

Muscle soreness is a multifactorial phenomenum, happening both in consequence of excess muscle damage and the inflammation state induced by exercise (study).

It seems like the damaged muscle fibre itself is one of the main cause of inflammation after exercise (study)

Causes of muscle soreness from working out

Eccentric Loading and Muscle Soreness

The more stretched the muscle, the more tension it needs to create to overcome the applied force (study). It contributes to muscle hypertrophy, but it also induces muscle soreness to a large extent (study).

Eccentric exercises such as Romanian Deadlift, Good Mornings,... are recommended for muscle hypertrophy.

But abusing of these can produce large amounts of muscle soreness, and, consequently, compromise performance and recovery.

Eccentric Exercise and Muscle Soreness

Metabolites Accumulation

When you exercise, your muscle starts to 'burn'. That is the end-product of the accumulation of secondary metabolites on the muscle fibre (study).

Also called metabolic stress, it's one of the main mechanisms driving muscle hypertrophy.

The metabolite accumulation also contributes to muscle soreness. Metabolites lower the pH of the muscle cell, creating an acidic environment.

This will disturb the physiological pH of the muscle, and will lead to future adaptations and muscle soreness.

Metabolic stress also induces hypoxia conditions (restricted oxygen supply). Because there's no enough oxygen, oxidative stress increases in the form of ROS (Reactive Oxygen Species).


Intense Workout

Any intense physical activity taken close to muscle failure will create muscle soreness.

Intensity is directly proportional to muscle damage (study). The higher the intensity, the more muscle damage, and the more muscle soreness from workout you'll have.

However, your body can adapt to the intensity, producing less and less muscle soreness over time.

Exposure to a New Exercise

New exercises are usually one of the main cause of muscle soreness. They create a new stimulus, and your body is still not adapted to that situations, neither are your muscles.


Until you are adapted, that new stimulus will create a new tension pattern in your muscle tissue, leading to inflammation and consequent muscle soreness (study).

Adding a new stimulus in your routine will most likely end up in muscle soreness for a few days.

Causes of muscle soreness from working out

What Helps Relieve Muscle Soreness from Working Out

Muscle soreness from working out can happen. Although you don't need them to build muscle, they are a good signal of progress and muscle adaptations.

I'm sure you don't like the feeling of muscle soreness. Here, we'll look at a few strategies you can do around the workout session to relieve muscle soreness.

techniques to reduce muscle soreness

Active Recovery

An active recovery will help you to relieve muscle soreness from working out. Active recovery is one of the most effective methods to fight muscle soreness (study).

Doing the correct active recovery also contributes to prevention of muscle strength loss, improvement in flexibility, and a decrease in inflammation.

This active recovery protocol depends on your preferences. But don't follow high intensities and take it easy.


Light Aerobic Exercise

Aerobic exercise increases blood flow and oxygen delivery to the muscle (study).

Increased blood flow will wash off the accumulated waste products that led to inflammation.

Increased oxygen on the muscle cell will fight the oxidative stress caused by excess ROS (study)

Stay Hydrated

Hydration and reposition of electrolytes is key to relieve muscle soreness from working out.

Sweat is composed of water and electrolytes, mainly sodium and potasium. The loss of these during the workout session deteriorates muscle contraction and smootheness of muscle function (study)

In this study (study), the hydration group, compared to the control, showed higher increases in body mass post-exercise and lower subjective muscle soreness.


Post-Workout Meal

The post-workout meal plays a key role on relieving muscle soreness from working out.

The post-workout meal provides enough nutrients to overcome that catabolism and induce the anabolic response that will trigger muscle hypertrophy and recovery of damaged muscle (study)

To follow the correct post-workout nutrition we should mainly focus on two nutrients: protein and carbohydrates


Protein is the main macronutrient responsible for muscle hypertrophy (study). It provides sufficient amino acids to both create and repair muscle tissue.

During the workout session, a lot of muscle has been damaged. Post-workout protein intake will help relieving muscle soreness and improving the recovery process (study)


During the workout session, the available glucose and glycogen stores will be used up. Post-workout carbohydrate intake can help you refill the used glucose and glycogen and improve muscle recovery (study)

Carbohydrates are also responsible for stimulate insulin production and release. This hormone plays an important role in muscle hypertrophy (study).

Carbohydrates intake will indirectly help you build more muscle and reduce muscle soreness.


Muscle soreness from working out is a common consequence of intense exercise. Although the mechanisms are still unknown, muscle soreness seems to be a cause of increased inflammation and oxidative stress in the muscle cell, as well as excess muscle damage.

In this post we've seen what are the main causes of muscle soreness, and what you can do to help relieve it. If you still have doubts, leave it below in the comments section.

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