Rapid recovery for muscles is important to achieve optimum performance. What should we do?

Unaccustomed exercise or intense exercise can damage the muscles. A robust recovery from such damage is very important for achieving optimum performance from the next day onward. In this section, we'll look at what kind of damage occurs in your muscles by your daily workouts and how important it is to recover quickly from the damage that has been sustained.

1. Exercise damages the muscles!

First of all, it is very important to know what kind of movement the muscles are performing during exercise in order to take appropriate care of the muscles after exercising.

Shortening of the muscles length during lifting of an object is called contraction. There are two major types of contractions (Fig. 1).

・Contractions that exert force while shortening the muscles (concentric contractions)
・Contractions that exert force while lengthening the muscles (eccentric contractions)

Concentric exercises include exercises for lifting weights and climbing stairs and slopes. Eccentric exercises include weight-lowering exercises, climbing down stairs and slopes, and stop-and-go exercises.
We know that people are more likely to damage their muscles when they perform eccentric exercises that lengthen their muscles.

Figure 1

Muscles are composed of bundles of elongated cells called muscle fibers. These muscle fibers are arranged neatly, but if the muscle is damaged by continuous "eccentric exercises" (more likely to damage the muscles), the muscle fiber rows are disordered as shown in Figure 21).

The muscle damage can also cause muscle pain, muscle weakness 2), as well as muscle tension, swelling, and reduced range of motion in the joints. These various problems increase the risk of injury and negatively affect the skill acquisition.

Figure 2

The musle damage can cause inflammation (redness or swelling of some parts of the body) at the damaged site. These conditions make it difficult for carbohydrates (glycogen) to recover in the muscles that decrease with exercise, even though there are sufficient amount of carbohydrate for glycogen storage 3). If you continue to exercise every day, you are more likely to experience accumulated fatigue. Muscle damage is thought to be one of the causes of these problems.

For sportspersons, more serious problems include difficulties in achieving optimum performance when the muscles are damaged 4). There are adverse effects in terms of technical aspects.
Consequently, it is very important to know how muscles recover effectively from the damage they incur so that you can train the next day in the same way, or achieve optimum performance in important matches and races.

1) Raastad T, et al. Med Sci Sports Exerc. 2010; 42(1): 86-95
2) Shimomura Y, et al. Int J Sport Nutr Exerc Metab. 2010; 20(3): 236-44
3) Costil DL, et al. J Appl Physiol 1990; 69(l): 46-50
4) Leite CMF, et al. Hum Mov Sci. 2019 Oct; 67: 102504

2. It takes time for damaged muscles to recover

If muscles are damaged considerably, it may take several days to nearly two weeks for them to recover back to normal. Hence, when you train hard everyday, it is important to take care during daily training to keep the muscles in the desired condition for the next day of training and the actual competition such as a match or a race. To do so, diligent care is required so that you can recover as soon as possible after the training has ended. Next, we will discuss damage to the muscles, how they recover, and the changes that occur within the body.

If the muscles are damaged by exercise, inflammation may occur, as previously explained 5)(Fig. 3). If the muscle damage sustain seriously, inflammation can also be severe, which can further damage the muscles. Have you ever experienced increased fatigue or sore body after doing very intense exercise, long hours of training, or undergoing a new training routine that you are not familiar with? These symptoms may be attributed to inflammation in your body.

Figure 3

In light of the above, if you train every day, it is important to combine your training regimen to suit you, and make every effort to ensure that muscles are recovered on a regular basis. Another important point is not to train too hard before an important match or race.

5) Peake J, et al. Exerc Immunol Rev. 2005; 11: 64-85

3. Synthesis of new protein is important for restoring muscles to their original state

Muscles can break down if they are damaged. Consequently, it is necessary to synthesize new muscles to replace those that have been degraded (Fig. 4).

Cells that make up muscles, contain a lot of proteins. Actin and myosin proteins are abundant in these cells. These proteins mainly work when the muscle contracts during exercise.

In order to replace a broken muscle cell again, it is always necessary to make new proteins that will serve as the building block for those cells.

Our body's proteins are made up of 20 kinds of amino acids. These kinds of amino acids can be divided into two categories: the nine essential amino acids that cannot be produced in the body i.e., need to be obtained from meals, and the 11 non-essential amino acids that can be produced in the body. Of these, the nine essential amino acids help make muscle proteins.

We also know that amino acids are not simply used as a building block to make muscle proteins. Amino acids can serve as a 'switch' for synthesizing new muscle proteins 6. In particular, one of the essential amino acids, leucine, is responsible for activating this switch.

Figure 4

In light of the above, proteins and amino acids high in essential amino acids and leucine are helpful in the recovery of muscles after exercise.

6) Ge Y, et al. Am J Physiol Cell Physiol 2009; 297: C1434–44

4. Summary

It is important to be aware of the following points to enable quick muscle recovery and to be in great shape for the next training, match, or race.

  • ・Muscles are susceptible to damage with 'Eccentric exercise' that lengthens muscles.
  • ・If a muscle is damaged, it will be difficult to continue to train the next day or achieve optimum performance.
  • ・It takes time for damaged muscles to recover to their original state.
  • ・It is important to produce new proteins to restore muscles.
  • ・Proteins high in essential amino acids and leucine are used to make muscles.

Exercise and training are not over as soon as you finish. You must think about what kind of after-care will enable quick muscle recovery and perform well diligently. This will help you to know your body and to achieve your ideal performance. Learn and use the right knowledge to recover as quickly as possible from the damage caused by exercise to achieve your ideal performance (Fig. 5).

Figure 5

▼Here are the amino acids that solve this problem.
A "Leucine-enriched essential amino acid mixture" maintains the condition of muscles during exercise! It also supports recovery from fatigue after exercise!


Supervising Editor:Satoshi Fujita


Satoshi Fujita
Professor, College of Sport and Health Science, Ritsumeikan University. ● He completed a doctorate - Ph.D. (Exercise Physiology) at the Graduate School of the University of Southern California in 2002. ● After his position as a lecturer in the Department of Internal Medicine, University of Texas Medical School in 2006, he was appointed as Special Assistant Professor at the Graduate School of Frontier Sciences, The University of Tokyo in 2007. He then assumed his post at Ritsumeikan University in 2009. He has received awards from the American Physiological Society (APS) and the American Society for Nutrition (ASN). His specializations are exercise physiology and the metabolic response of the skeletal muscles influenced by exercise and nutrition. ● Edited publications include "An illustrated guide so interesting you won't be able to sleep" and he has co-authored "Sports Nutrition for Physical Education and Sports Instructors and Students".

■About Professor Satoshi Fujita’s Laboratory
Professor Satoshi Fujita's laboratory in the College of Sport and Health Science, Ritsumeikan University, focuses on an investigation of the effects of exercise and nutrition on body composition and sports performance. From basic research examining muscles at the molecular level to clinical research targeting a wide range of ages (from children to the elderly) and physical fitness, they continue to conduct daily research toward building evidence for sports science that can help those in the field of exercise instruction using an integrated experimental approach. Specific studies are listed below:
1) Investigation of the effects of combining specific functional foods and exercise on lipid metabolism and skeletal muscle protein metabolism
2) Consideration of long-term training and nutrition interventions aimed at sarcopenia (age-related muscle attenuation).
3) Development of training methods for enhancing the sports performance of junior athletes.

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