Soreness and DOMS a Brief Review

We have all experienced it many times, yet no matter how often or rarely it occurs it's always a pain in the...well you know. You're sore the day or two days after your workout. Some of the muscles you used are tender to the touch, weak, and ache when you work them through a complete range of motion. What is the cause of soreness, what is DOMS, and what can you do?

The cause of soreness has been up for debate in recent history. Up until recently soreness following a bout of exercise has thought to be due to lactic acid accumulation in the body. Exercise scientists even gave soreness that rears its ugly head 24-48 hours after exercise a fancy moniker- delayed onset muscle soreness or DOMS. This is known as the metabolic theory. In this theory high intensity repetitive exercise causes the muscles to use highly anaerobic pathways to create energy for the contracting muscle, causing an excessive production of lactic acid. This lactic acid floats around the blood stream until it is removed by buffering agents within the muscle when it has sufficient oxygen to do so, or by the liver as it passes lactic acid off to the Cori cycle to create glucose to be stored as glycogen in the liver or muscle. With me so far? This was thought to be the burn experienced during exercise, when lactic acid production exceeded lactic acid clearance by the body, excessive lactic acid concentrations were thought to cause the burn, pump, and also cause soreness. What a crock! :-)

The first problem with this theory is that lactic acid cannot even exist in the body under normal human physiological conditions. To be clear, it is LACTATE not lactic acid that is produced by the anaerobic pathway used by muscles during high intensity exercise. Lactate is not capable of forming the acid (lactic acid). Second, lactate is readily cleared, converted, or even used by various metabolic pathways in the body to create more energy. So why do we get fatigued, experience a burn, pump, etc?

During exercise movements there are usually two phases of the movement, a concentric and an eccentric. If we take the squat for example, the concentric is the UP phase or the lifting phase, while the eccentric phase would be the down portion, and it is more passive. However, it is the eccentric phase that causes the muscle damage responsible for fatigue, burning sensation, pump, and muscle soreness. During the eccentric portion of a movement, the muscle is stretched into an elongated position. In the case of the squat the hamstrings, glutes, and adductors are stretched. Moreover, they are loaded with weight, either by a bar and weight, or simply your own body weight. When a muscle is both stretched and loaded small microtears occur in the muscle tissue, specifically the muscle cells. This has a dose-response relationship in that the more the muscle is stretched, loaded, or when the velocity of the movement increases so do the amount of microtears in the muscle. Furthermore, when the movement is repeated many times, more and more microtears occur. The tearing of muscle cells (on a microscopic level) allows internal cell chemicals to seep out into the blood stream. Some of these chemicals include creatine kinase, myoglobin (the oxygen carrier within muscle tissue), and hydrogen ions.

If you think back to your chemistry class you remember that hydrogen is associated with being acidic. To take that one step further, it affects the pH balance of any solution, and in the body this occurs in the blood, muscle tissue, etc. The normal pH of the body at any one given time is about 7.2. Any deviation from this pH results in serious issues such as gastric dumping, protein degradation (organ and tissue degradation), reduced function, and in severe cases death. This is why the body will undergo many functions and processes to prevent a change in the pH body-wide. However, in localized muscle tissue, hydrogen ion accumulation from intense exercise involving eccentric muscle contractions occurs. This increase in localized hydrogen ion concentration causes a slightly acidic situation in the muscle (remember acidic = a pH of <7.0>7.0). With the muscle being slightly acidic the body gets into a fury of activity trying to repair, remodel, and rid the tissue of the acidosis incurred.

Remember the body's main repair pathway for any tissue, cell, organ, etc is the inflammatory pathway. When the muscle is damaged and subsequently in an acidic state the inflammatory process is signaled. Basic inflammatory responses include an increased blood flow to the area (vasodilation), immune system cell infiltration, swelling, redness, pain, etc all in an effort to repair and remodel the effected cells. So the hydrogen ion accumulation from the microtears in muscle tissue causes the inflammatory pathway to go to work and in conjunction with the immune cascade causes soreness which can occur either directly after a bout of exercise or 24-48 hours afterwards.

But this is not necessarily a bad thing. The body has what is known as a general adaptation syndrome to all stressors. When you stress a muscle to a point that damage occurs, the body rebuilds and remodels it to a point to better cope with the stress. Once the muscle is completely recovered a similar bout of exercise should cause less soreness than before and work capacity of the muscle or body should increase. However, in the training world since we are constantly trying to progress, we tend to never see the exact same stimulus over and over again. The goal is to progressively overload the body in such a way to force it to get bigger, faster, stronger, and prettier. Think about it, say the workout involved 50 squats and that made your legs really sore. After you recovered, the next time you saw 50 squats in a workout you would either add resistance, move faster through the number of squats, or some other measurable improvement. So now the stimulus has changed and the body is again, forced to adapt.

Soreness is not necessarily a marker of a good workout, or a bad one. Depending on someones recovery ability they may be sore very infrequently or very often. To break this down even further, the inflammatory pathway only has a set capacity that it can deal with at any one given time. If your body is chronically inflamed in other tissues such as the blood vessels, joints, brain, organs, etc and now you add in acute muscle inflammation then the recovery will be slower and soreness is likely. Conversely, if you don't have much, if any, chronic inflammation going on you will quickly recover from exercise as the inflammatory pathway can work swiftly, unabated by other nagging inflammation. Make sense?

Even so, a very fit person with excellent recovery capacity can become sore from workouts involving repetitive eccentric portions of movements. Especially if the weights are heavy, the reps are many, or the velocity is high of the movements. But don't be so quick to drop kick the eccentric portion of exercise. Studies have shown that concentric-only based strength programs fail to provide any increase in strength, muscle hypertrophy, or work capacity. So we need the eccentric portion, but we need to program training sessions properly to make sure that adequate recovery is attainable and consistent progress can be made.

Can you exercise, stretch, foam roll, massage your way out of DOMS? Studies have also shown that light exercise can help alleviate DOMS by increasing blood flow to the effected muscle tissue and thereby increasing the clearance of inflammatory, immune, and metabolic by products lying around in the tissue causing discomfort. In contrast, stretching has shown no benefit to decreasing soreness, particularly static or ballistic stretching. A Dynamic warm up and proprioceptive neuromuscular facilitative stretching (PNF) have shown slight decreases in discomfort and an increase in the effected muscle's force production. Foam rolling has been postulated to decrease recovery time, and is smart practice pre and post exercise to yield the fastest recovery time possible. Massages, while relaxing and fun, offer no increase in recovery capacity, force production, etc.

Perhaps the best way to decrease your chances of soreness is to properly warm up, use proper bio mechanics during exercise, and utilize a sound nutritional approach that decreases body wide inflammation so you can use that inflammatory pathway to recover the effected muscle instead.

Sorry for the long post, if any body has any additional questions email me at jfeigenb@gmail.com