About the Author: Tony Webster has a Ph.D. in exercise physiology and currently works within the Pacific Institute for Sport Excellence at Camosun College in Victoria, Canada. He has his Level 1, basic barbell and Olympic lifting certifications through CrossFit. He trains with the crew at CrossFit Taranis, where he enjoys getting his ass kicked by coaches Reed and Dan.
Consequences of muscle damage: Temporary swelling and pain, lower power and range of motion, and tremor
The main consequence of muscle damage that we all feel is DOMS. This is soreness that first appears about eight hours after the exercise bout and typically peaks about 24-48 hours later. It’s particularly noticeable when you get out of bed in the morning. We experience muscle tenderness, pain when we touch the muscle, and stiffness that causes pain when we move or stretch it. With some gentle movement the pain usually subsides, but after prolonged periods of little movement (sitting in front of a computer, for example) it rears its ugly head again. Usually the DOMS will have mostly disappeared after about four to five days, but can persist for longer in some cases, as most CrossFitters can tell you.
So why do we get sore? It seems reasonable to speculate that it evolved as a way to tell us to “ease off” while the muscle is recovering. To repair the microdamage to the muscle fibers, the body initiates a local inflammatory response that starts the healing process. As we all know, inflammation is usually accompanied by pain, swelling and redness. Since the inflammation is inside the muscles themselves, we can’t see the redness (increased blood flow) or the swelling, but we can sure feel the pain! So you might be thinking, “Maybe I should just pop an anti-inflammatory?” Well, not so fast—we’ll discuss that later.
In addition to soreness there are a number of other things that happen as a result of muscle damage. In most cases after muscle damage, the membranes of muscle fibers are compromised, allowing substances to spill out into the bloodstream. These include muscle proteins like creatine kinase and myoglobin, and certain electrolytes such as potassium. In the vast majority of cases, these effects are entirely normal and reversible, but in very rare cases the spillage is excessive and can lead to serious medical complications.
Further consequences of muscle damage include loss of muscle function—the muscle does not recover its strength and power capabilities for at least several days after the exercise bout. One may assume that the muscle is fully recovered when the soreness has disappeared, but the time course of soreness and strength loss is not as closely linked as one might think. The muscle may feel fine but may not recover its full force capability for a few more days. Loss of muscle function in the days after a hard muscle workout can also be seen in the form of shortened (contracted) muscles at rest and an inability to contract fully. In other words, the range of motion through which the muscle can effectively operate is significantly reduced while it is recovering. Studies have also shown that during recovery from muscular overload there are significant changes in our gait biomechanics, and that there are significant decrements in sprint and endurance performance. There is also evidence that damaged, sore muscles have reduced insulin sensitivity and thus are less able to recover their normal glycogen levels.
Silver lining: Less damage and pain next time
It’s called the “repeated bout effect.” This refers to the fact that another similar bout of exercise will not have the same consequences as before. We all intuitively know this. This is what training is all about: improving our muscular work capacity and recovery capabilities. The exact “black box” adaptations within the muscle that are contributing to the repeated bout effect have not yet been elucidated, but they are probably a combination of increased structural strength of muscle fibers, metabolic adaptation and neuromuscular changes. A key point is that if we go back to being a couch potato, all that good work and adaptation will disappear within a few weeks.
Pain a la CrossFit: Fast, high-rep, full-range movements are a potentially potent cause of DOMS
Think about the types of CrossFit workouts that make you sore. What are they? The thing that has surprised me most about CrossFit is the degree and depth of soreness that one gets from the high-repetition bodyweight workouts.
Research has shown that faster eccentric contractions tend to cause greater strain and thus greater damage within muscle. This is why many people really notice soreness after workouts that involve explosive and/or jumping type movements. With a high-repetition bodyweight workout such as Cindy.
There is also good evidence to suggest that there is a length-dependent component in the development of muscle damage. Muscles that are stressed quickly and eccentrically while simultaneously being close to their fully stretched position (think about the quads, adductors and glutes in the full squat position during wall balls, for example) are more likely to become damaged than if the eccentric action occurs only during the mid-range of movement or earlier (i.e., if you fail to squat down adequately between reps). Thus CrossFit’s emphasis on quality full-range movements performed at high intensity is a perfect recipe for muscle damage and repair, i.e., adaptation.
Practical recommendations: Go easy on extremely sore muscles, don’t expect much from stretching and massage
Should you train if your muscles are sore? There are many fitness experts who would tell you a flat “no.” Well, the real answer is: it depends. You are the owner of your body and you need to make that call for yourself. Mild to moderate DOMS is unlikely to be a problem. However, if you have severe soreness in a particular muscle group I would suggest that you provide that body part with some relative rest.
Note that chronic muscle soreness that seems to linger for longer than usual may be a sign of over-training, or under-recovery, whichever way you choose to look at it. If you are feeling unusually unenthusiastic about your training, and you are noticing chronic muscle soreness, you would be well advised to listen to your body and take appropriate rest until your body and mind are back in the game.
Remember that muscle damage and soreness are essential and probably unavoidable pre-requisites for optimal muscular adaptation. If you have an aversion to feeling sore, you can either stop doing CrossFit (not an option for most!) or reframe your attitude. How? Try any or all of the following:
- DOMS can make you feel less guilty about taking rest days.
- DOMS is a sign that your body is adapting.
- DOMS gives you valuable delayed feedback about your performance in the exercises concerned.
As an explanation for point 3, let’s say you have done a heavy deadlift 3-3-3-3-3 WOD. You can expect that you will feel some soreness/fatigue in the lower-back muscles in the days after this workout, as it is primarily a low-back exercise. But if you notice excessive soreness in an unusual place, this may be a signal that your technique might need some work. If you keep a log or record of your workouts, you should make a note of where you felt sore and use this information to help you tweak your technique the next time.
How about stretching? Can it reduce muscle damage and DOMS? First, gentle stretching of a muscle that is already sore is perfectly acceptable, is not likely to negatively affect muscle recovery, and can be used to minimize the short-term sensation of pain and soreness. But what about post-exercise static stretching? It is often claimed that static stretching after a hard workout can reduce muscle soreness in the coming day(s). Well, now that you understand the initial cause of muscle damage (microtears within the muscle fibers), you should also appreciate that this claim simply does not make sense. Is stretching after a hard workout going to “undo” the damage in some magical way? Clearly not. And scientific studies have also consistently failed to find an effect. Static stretching after a workout when the muscles are warm is an excellent idea and, when done on a regular basis, can significantly improve muscle extensibility. This improved flexibility may assist in improving performance and probably assists in preventing strain type injuries. But let’s be careful about claims that we make for post-exercise stretching and short-term DOMS.
How about warming up and stretching prior to a workout? Can this influence the DOMS that we may experience? It would seem logical to suggest that warming up might offer some protection against muscle damage by increasing muscle temperature and “loosening” up the muscle(s) concerned. Unfortunately, there is minimal evidence to support this either! Of course, this should not be interpreted as a reason not to warm up—warming up can improve subsequent performance and potentially minimize the chances of muscle strain injury. Just don’t expect that you will necessarily be protected from DOMS in the days afterwards.
What about massage after exercise? While it may be very relaxing and assist in general recovery, there is no conclusive evidence that this will reduce the extent of DOMS. Cryotherapy (ice) also appears to have minimal effect. And this brings us to anti-inflammatory medication. Popping an ibuprofen or other non-steroidal anti-inflammatory drug to reduce DOMS might seem like a good idea, but is not recommended. It may indeed reduce the amount of discomfort that you feel, but (a) soreness is there for a reason and by artificially reducing it you run the risk of further injury to a muscle, and (b) there is good evidence that anti-inflammatory medication can slow down the adaptive processes in muscle.
Conclusions: Progress sensibly and don’t take long layoffs
So the bottom line, as with other things in life, is that there is no easy ticket. Muscle damage and soreness should be accepted as what it is—useful feedback from your body telling you to give the muscle(s) concerned some relative rest. Everybody has a different body and you must learn to listen to yours. One of the beauties of the CrossFit approach is that if you are away from your gym for a significant time it is easy to concoct workouts consisting of air squats, push-ups, pull-ups and sit-ups, etc. If performed at high intensity, these will prevent your muscles from “de-adapting.” Oh, and a final word of advice: take at least 10-15 minutes to stretch after your workouts. Though this may not necessarily protect you from DOMS, the increased flexibility will make you feel better and may improve your performance.