Muscle fatigue in running represents one of the main challenges both for runners who are just starting out in this discipline and for the more experienced.
That feeling of heaviness in the legs, decreased performance or even cramps can ruin a training session or an important race. In this post, we explain why muscle fatigue occurs, how to prevent it and what strategies you can apply to combat it effectively.
What is muscle fatigue and why does it occur?
Muscle fatigue is the temporary decrease in the muscle’s ability to contract efficiently. In the context of running, it usually appears after prolonged or intense effort and can be caused by different factors, such as:
Overload and lack of rest:
The most common and usual factor. An excessive training load without adequate recovery time can lead to accumulated fatigue. Muscles require rest and recovery. It is necessary to respect rest periods between each training session so that the muscles have the time they need to repair and strengthen.
In addition, not resting properly can end up increasing the risk of injury.
Dehydration and loss of electrolytes
Through sweat, the body loses essential minerals such as sodium, potassium, magnesium and calcium, which are crucial for muscle contraction and nerve transmission. A lack of these electrolytes can lead to cramps, weakness and premature fatigue. That is why you should consider factors such as the weather and training duration, as supplementation with salts before, during and after exercise may be useful for preventing it.
Energy deficit:
A low level of muscle glycogen can cause an energy deficit. Glycogen is the main source of energy during aerobic exercise. If you have not consumed enough carbohydrates before training, or if the session is excessively long, your glycogen stores become depleted, resulting in the onset of fatigue.
Inadequate technique or unsuitable footwear:
Fatigue can also be caused by incorrect technique or the use of unsuitable footwear. Poor posture, misaligned foot strikes or running in worn-out shoes can create uneven strain and overload certain muscle groups, thus accelerating the onset of fatigue.
What are the main symptoms of muscle fatigue?
The most common symptoms of fatigue are:
Muscle pain or discomfort:
It manifests as increased tension or even slight twinges in the muscles, especially in the quadriceps, hamstrings and calves.
Lack of coordination or clumsiness:
Your technique becomes less precise, your foot strikes change and you may experience trips or unstable steps.
Cramps:
Muscle cramps are involuntary and painful muscle contractions. You can try to prevent them by avoiding dehydration and maintaining electrolyte balance.
Heaviness in the legs:
You feel that your legs are “loaded” or heavier than usual, making it difficult to maintain your normal pace.
Decreased performance:
You find it difficult to maintain your speed, pace or running technique, even if you are not breathing heavily.
Tips for preventing muscle fatigue:
1. Warm up properly:
To promote circulation and reduce the risk of early fatigue, spend 5 to 10 minutes before running activating your muscles and joints, for example, by including dynamic exercises.
2. Stay properly hydrated:
The loss of fluids and electrolytes can cause fatigue and cramps. Make sure to drink water before, during and after exercise, and include salt supplements or isotonic drinks when necessary.
3. The importance of proper nutrition and carbohydrate intake:
Make sure to consume enough carbohydrates before running, as they are the main source of energy during exercise. A balanced diet should also include protein, healthy fats, vitamins and minerals.
During long races, you may consider using energy gels, gummy bars or another supplement that provides rapidly absorbed carbohydrates. This type of carbohydrate helps us maintain performance, especially when our muscle glycogen stores begin to run out.
4. Strengthen your muscles, rest and relieve muscle tension:
Strength training specifically designed for runners helps prevent muscle wear, improve running technique and better withstand prolonged effort.
Other useful tools you can put into practice include:
- Massages or using a foam roller are excellent for relieving muscle tension.
- Make sure you get enough sleep, as it is during sleep that muscles repair themselves and adapt to exertion.