The sensation of delayed onset muscular soreness that results from muscular overuse is an almost universal experience. Anyone involved in occasional exercise, Athletics, heavy manual labor or other forms of occasional muscular overexertion has at times experienced the temporary stiffness and tenderness associated with DOMS. So what is DOMS?…
' Unaccustomed exercise or any form of muscular overexertion may lead to tenderness and temporary stiffness approximately 12-24 hours after completion of exercise, this odd painful sensation is referred to as delayed onset muscular soreness'
…Gradually the DOMS sensation intensifies and peaks 24 to 48 hrs after exercise. The sensation of tenderness and stiffness in the muscles can last upto 5 to 7 days after exercise. It is said to be transmitted by the group IV unmyelinated fibers. Despite the vast prevalence of this experience, the underlying cause of DOMS are not yet fully understood. But DOMS is said to exhibit certain fixed Characteristics…
Line:1 Predominance with eccentric contractions.
The degree of discomfort depends to a large extent on the intensity, duration of effort and the type of exercise performed. In 1987 JA SCHWARNE stated that Eccentric to a large extent and isometric muscular contraction to some extent cause the greatest post exercise discomfort.
Line:2 Reduced or absent in regular exercises.
Surprisingly one or two training sessions are necessary to prevent the recurrence of DOMS. But only well trained individuals are likely to avoid other adverse consequences of exercise induced muscle damage.
Line3 Transient reduction in muscle strength and ROM
According to Peter M Tiidus 1990. During DOMS time course the range of movement about the joint that is flexed or extended by the affected muscles is usually reduced. Temporary loss in muscle strength and power also coincides with DOMS sensation. Strength loss may persist for several weeks even after the sensation of pain has disappeared. The reason for this is discussed further in detail in the section dealing with causes of DOMS.
Line:4 100% spontaneous recovery.
In almost all cases of post exercise muscle discomfort, the pain persists maximum upto 3 - 10 days and does not leave a residual damage. This could probably be a reason for DOMS to have lost its clinical significance , But it is the duration of discomfort which matters and should be treated.
The Metabolite Theory: This theory gained great popularity in the lay exercise community. It was first proposed by scandinavian researches in1930.Prolonged exercise that follows a layoff causes an accumulation of metabolites in the muscle. This accumulation triggers osmotic changes in the cellular environment and fluid is retained. The edema caused by increased osmotic pressure excites sensory nerve endings and causes pain.
Factors not in favor:
The explanation provided is inadequate. It should be recalled that muscle soreness was much greater following eccentric exercise than static or concentric exercise. The metabolic stress of concentric work however is usually 5 to 7 times greater than that of eccentric work. Consequently one would expect the metabolic build up and accompanying soreness to be greater in the concentric exercise, but it is not so, which puts a question mark behind this theory.
The spasm hypothesis: In 1961 De Vries proposed that exercise induced muscle pain caused a feedback cycle, leading to muscle spasm. This in turn induces yet more pain due to local ischaemia and metabolic waste accumulation .
The factors not in favor of this theory:
There was no marked increase in the resting EMG activity, which would have been anticipated with muscle spasm in the sore muscles. But in some cases the EMG activity was reduced after static stretching.
The tear theory: This theory has been gaining importance since 1985, it is said to be the most apt theory so far,
Exercise induced morphological muscle damage has commonly been reported to occur in association with DOMS sensation. Such damage is usually seen immediately after exercises as small areas of focal damage. These become more extensive over the next several days. The main signs are z- line and myofibrillar disruption. Severe damage is readily evident in transverse sections using a light microscope and there may be a reversible atrophy of some affected fibers.
In animal studies, Exercise induced muscle damage is accompanied by activation of lysosomal enzymes and invasion of macrophages. Fiber necrosis is evident for several days and is accompanied by inflammation and edema. Regenerative processors are evident even after 3 days. Most of the degeneration and damage is delayed and thus cannot be seen some hours after exercise. Which explains the delay in onset of soreness.
However these experiments are on animals, and how these necrotic regenerative developments relate to the DOMS sensation in humans is uncertain.
Factors not in favor of this theory:
Though experiments proved increased excretion of substances like myoglobin, hydroxyproline etc in urine in DOMS affected individuals which are suggestive of muscular damage. These are also excreted after severe exercise in athletes who do not have DOMS sensation.
The calcium ion Theory: In 1983 Armstrong and Edward suggested that increase in calcium ions in muscle cytoplasm may be a factor in the cascade of events that lead to post exercise muscle damage and DOMS sensation. Damage to the muscle sarcolemma could lead to high calcium ions that inhibit mitochondrial respiration. The elevated calcium concentrations could also activate certain protease and phospholipidase enzymes and attract monocytes. The resultant accumulation of histamine and kinins may be stimulating the type IV afferent nerve fibers that carry DOMS sensation.
DOMS has been fascinating the field of therapeutic research in the past twenty years.
DOMS &Pulsed ultrasound:
This study was done in Texas, the purpose of the study was to compare the analgesic effect of pulsating ultrasound treatment and placebo on DOMS produced by eccentric exercise on 18 untrained subjects. It concluded stating that pulsed ultrasound accelerates restoration of normal muscle performance and thus is effective in treating DOMS. The mechanism may be related to decreasing intramuscular pressure and or decreasing the inflammatory response.
Another study investigating the effects of 2 doses of pulsed ultrasound on 48 healthy volunteers concluded that when ROM was considered as a parameter
Pulsed US was effective, but when pain was considered as a parameter ultrasound did not prove to be an effective method of treatment of DOMS.
Post exercise static stretching and DOMS:
A study done in 1989 concluded that warm up and stretching prior to exercise had significant role in preventing DOMS sensation.
Another study done in 1998 to evaluate the effect of static stretching on DOMS concluded that passive stretching did not have any significant influence on DOMS sensation.
Massage Microcurrent electrical stimulation and DOMS:
A study in 1994 concluded that there was not statistically significant differences between experimental group treated with massage and Microcurrents and the control group.
Post exercise cold application:
This study was done in 1984, the study concluded that there was significant reduction of DOMS sensation after post exercise application of Ice Massage.
Thus we see that recent researches have been showing varied results, necessitating further research to define a definite protocol for the treatment of DOMS.
Exercising sore muscles:
In his pioneering work on muscle soreness Dr Hough noted that exercising sore muscles appeared to relieve the soreness temporarily. The most likely explanation for this seemingly paradoxical observation could be exercise induced increases in afferent discharge from low threshold sensory fibers of groups Ia, Ib, ans II. These fibers could partially block the pain sensation carried by the small, DOMS sensing group IV fibers through interneurons located in the spinal cord .Another possible explanation could involve the elevated levels of endorphins that accompany exercise. Nevertheless exercise offers only temporary relief and DOMS sensation returns shortly after exercise is stopped.
Application of Methylsalycilate creams:
The local sensation of cutaneous heat generated by the creams may temporarily attenuate the DOMS sensation possibly owing to the blocking mechanism discussed above.
Ice Massage:
Ice has found to have good effect in releiving edema and reducing inflammation. But these may not be primary or singular causes of DOMS.
So the result may extremely vary as the recent researches show.
Saunas, Whirlpool baths and Massage:
The use of these modalities has become popular among competitive athletes and their coaches. It is alleged that their regular use assists in quicker rejuvenation between workouts. What effects these interventions may have on DOMS are unknown.
Previous Training:
A single bout of exercise has a significant protective effect on the development of muscle soreness and damage in subsequent exercise. I t has been suggested that unaccustomed exercise damages a pool of susceptible muscle fibers. The subsequent degeneration - regeneration of these fibers decreases their susceptibility to further exercise induced damage.
Cooling down and stretching:
A period of low intensity aerobic exercises which is gradually reduced followed by few gentle stretching exercises helps in pooling of blood in the muscles and is effective in preventing myofibrillar necrosis after exercise thereby preventing DOMS.
Gradual progression in exercise programs:
The severity of onset of symptoms may be lessened by gradually increasing the intensity and duration of exercise programs.
In summary, the effective methods of treatment of DOMS sensation are continuously being sought. Since the exact cause of DOMS are yet undefined. It is not surprising that the various interventions that have been attempted in order to prevent and treat DOMS sensation have met with limited success.
In 1951 the noted muscle physiologist A.V.Hill wrote…
"I know nothing which prevents muscular soreness , except previous training , nor anything that quickens its disappearance . When asked I have often been forced to confess ignorance"
-A.V.Hill
Almost 4 decades have passed since the above confession was penned down. Still the fundamental causes and means of prevention and treatment of DOMS remain as elusive and as mysterious as they were then.