More precisely, it is the sensation of pain and apparent stiffness of the muscles that can be felt after training.
muscle mechanics).Although there is some variance between exercises and individuals, pain usually increases in intensity in the first 24 hours after training. The peak is between 24 and 72 hours, then subsides and disappears seven days after training. exercise.
training.
In fact, it is hypothesized that DOMS are caused above all by high intensity training based on eccentric contractions (muscle lengthening phase, also called negative). On the contrary, they seem to arise and last less after training based on isometric and concentric contractions.
Microtrauma theory
The reason must be sought on the mechanism underlying the phenomenon. To trigger DOMS would be microscopic damage to muscle fibers during training. According to the theory of "muscle damage", these breaks are caused by the Z line of the muscle sarcomere. This can cause the separation of the cross bridges of actin and myosin before relaxation, ultimately causing greater strain on the remaining active motor units. The risk of damage to the sarcomere would therefore increase. When microtrauma to these structures occurs, the nociceptors (pain receptors) within the connective tissues of the muscle are stimulated and cause a sensation of pain.
In practice, the muscle, which tries to adapt quickly to prevent more serious muscle damage, sends nerve signals of soreness each time a further muscle contraction is performed.
Theory of enzymatic efflux
Another explanation for the pain associated with DOMS is the enzyme efflux theory. After microtrauma, calcium that is normally stored in the sarcoplasmic reticulum builds up in damaged muscles. Cellular respiration is inhibited and the ATP required to actively transport calcium into the sarcoplasmic reticulum is also slowed down. This calcium buildup can activate proteases and phospholipases which in turn degrade and degenerate muscle proteins. This causes inflammation and, a in turn, pain due to the accumulation of histamines, prostaglandins and potassium.
Lactic acid theory
An earlier theory hypothesized that DOMS was linked to the accumulation of lactic acid, which was thought to continue to be produced after exercise. This accumulation was interpreted as "toxic and metabolic waste", responsible for the perception of pain in a delayed phase. This theory has been widely rejected, as concentric contractions that also produce lactic acid are equally unable to cause DOMS. In addition, multiple studies have shown that lactic acid returns to normal levels within one hour of exercise, and therefore cannot cause pain that occurs much later.
However, we could say that DOMS are a clear symptom of exercise-dependent microtrauma.
Note: DOMS should not be confused with acute pain, which occurs during or shortly after exercise, and is caused by trauma, contractures, strains or muscle strains.
, reduced range of motion and swelling. However, it has been shown that these changes develop independently over time, and that DOMS are not the direct cause of post-workout reduction in muscle function. confers 20 to 60% protection from muscle damage sustained by 100% strength exercise two to three weeks later. Moreover, such an effect is achieved even with a relatively small number of contractions - a couple. In one particular study, the first workout of 10, 20, or 50 contractions provided the same protection in the second workout of 50 contractions three weeks later.
The mechanism has not yet been understood and various mechanisms have been hypothesized, perhaps co-present. They include: neural, mechanical and cellular adaptations.
for example, in which maximum muscle hypertrophy is sought, warning the DOMS is quite important.This is because the hypertrophy training technique involves a massive use of eccentric training. If it is true that this technique causes numerous microtraumas, it is equally true that these microscopic injuries participate in the stimulation of muscle section increase.
We are not saying that this is the only predisposing factor for hypertrophy; training in eccentricity but without reaching high intensities and the right TUT, or without taking care of the diet, the increase in muscle mass would be mild. On the other hand, it is undoubtedly a fundamental requirement.
and warming up before or after exercise does not prevent DOMS.) is ineffective in alleviating DOMS or facilitating muscle recovery; not all research confirms this hypothesis.
Additional exercise can temporarily suppress pain, as training increases pain thresholds and pain tolerance. This effect, called "exercise-induced analgesia", is mostly known in endurance training (running, cycling, swimming), but little is known whether it also occurs in strength training.
In the literature it is frequently reported that training sore muscles appears to be the best way to reduce or eliminate pain, but this has not yet been proven systematically.
Treatments that increase blood flow to the muscles, such as low-intensity activities, massage, electrostimulation, hot baths, or saunas, can help.
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