You would not believe how common an occurrence this is during strength training or bodybuilding. Basically, what happens is a trainee notices that his biceps or some other muscle is sore to touch and with movement, maybe even a bit red or bruised looking. He or she figures they must have pulled a muscle during their last workout, but they never noticed a thing! No pain, nothing. How could this be? And why should it hurt so much now, say a day after the workout?
There is, in fact, an explanation for this, and not one based on anecdotal observations, but on clinically relevant facts about how muscle strains occur and heal. These muscles pulls that happen without us even being aware of them are called nondisruptive muscle strains. What we colloquially refer to as a muscle pull is more properly called a strain. The occurrence of these types of strains helps explain why so many trainees and misunderstand how muscle injuries occur, how they behave, and how they heal.
The first thing to understand, and this may come as a surprise, is that the majority of injuries that occur in the weight-room are not “severe”. They are relatively small and manageable strains. But they can LEAD to severe injuries when managed improperly.
It seems many “experts” are confused by how muscles act after a minor strain injury. They confuse “function” with adaptation.
While reading the last chapter of Practical Programming by Mark Rippetoe, for instance, I was absolutely floored. The author showed a complete lack of understanding of basic injury mechanisms and seems to think that hammering away at an injury will beat it into submission. Being that his main audience seems to consist of 13 to 16-year-old kids, many parents should be concerned as this kind of advice, in a therapeutic or medical setting, would amount of malpractice.
You don’t have to be a physiologist or M.D. to understand the common sense basics of muscle strains. But one thing to know is that the body’s injury mechanisms did not evolve to facilitate the lifting of heavy barbells over and over again. First, then, let’s cover some of the basics of muscle strain injuries.
How are Muscle Strains Classified?
Since I mentioned a “type” of muscle strains, it stands to reason that muscle strains are placed into different categories or classes. Muscle strains are graded based on their severity.
Depending on who you ask, there are three or four grades or “degrees” of muscle strain. The grading depends simply on the amount of damage done, from a percentage standpoint. And when we say percentage, we mean in terms of the muscle’s diameter, and therefore the number of fibers involved. Basically, this means we are considering how deep the strain is. Think about it in simple terms: Picture a muscle with a more or less round belly (although strains don’t tend to occur there). Imagine if, underneath the fascia, you took a knife and sliced through just a few muscle fibers, only ten percent or less of them. That would be minor injury to the muscle. Now imagine the most severe injury you could inflict..you slice through all the fibers…the entire muscle. That would be a Grade III or IV, depending on the grading system you prescribe to. So you see that it is how deep the “cut” is that counts.
Most Muscle Strains are Minor First-Degree
Most strain injuries during strength training or bodybuilding are first-degree strains. This means they involve only ten percent or less of the fibers. These minor strains do not really affect your strength much nor your range of motion.
Likewise, not all muscle strain is acute. Some of it is due to repetitive actions that cause cumulative “microtrauma.” Most of the time, you probably think of stuff like carpal tunnel syndrome, etc., but overusing one muscle in the gym, like because you have a biceps obsession, for instance, without adequate recovery, could cause this cumulative damage to the muscle tissue, not to mention the joint tissues.
In the image of a thigh muscle strain above, the extent of bruising indicates a severe strain that is at least grade II if not worse. It is unlikely that an injury such as this would leave one with full strength. Whereas more minor “grade I” strains do not result in appreciable loss of function in the muscle…therein lies the danger
What does acute mean? Acute refers to a medical condition, such as a muscular or joint injury that occurs suddenly resulting in a great change in well-being in a very short period of time, usually having a short duration. With musculoskeletal injuries the term “acute” sometimes refers to the first phase of the injury healing period, beginning just after the injury occurs to differentiate this period from the post-management period. Acute is used to describe the time-course of the onset of pain or illness and one that ends relatively quickly, either with recovery or death.
Either a minor acute strain or this repetitive trauma can happen right under your nose, so to speak, without you ever noticing it. When we do notice these things, it’s when they go from minor and asymptomatic (at least so you’d notice) to major and symptomatic.
If you’ve sustained this minor damage to a muscle and then later go in to lift, the muscle could be further damaged and become a more serious strain. So a Grade I strain can become a Grade II strain because the tissue is further damaged through use. But if that happened, you’d have a good chance of noticing it when it occurred. Wouldn’t you?
You May Not Feel a Muscle Strain When It Happens
You’d be surprised. Depending on the degree of damage, you might not feel it. Just like you can overuse muscle without feeling pain, you can use slightly damaged muscles without feeling pain. Continued muscular contractions have a slight analgesic effect. You may have noticed this before. For instance, if you have a bit of DOMS in your thighs and do some light barbell squats with moderate to high volume you’ll notice the soreness going away. This same phenomenon explains how you can sustain a strain, or make a minor strain a bit worse, without knowing it. Until several hours later or the next day when you notice tenderness, pain, and/or a reduction in the range of motion.
Nondisruptive Muscle Strains
These are the type of injuries I referred to as nondisruptive muscle injuries. They involve a strain to muscle fibers that is just short of their failure load. The immediate adaptation that takes place after these injuries is NOT, as many would have you believe, making that tissue stronger. What happens after injuries is not the same as what happens after normal training microtrauma and DOMs. The adaptation after successive exercise bouts leading to DOMS is protective in nature. You get less sore over time and the tissues can withstand more work.
The problem with nondisruptive injuries is that they fool us into believing we are “better” and can return to regular lifting activities, which often results in doing too much too soon leading to a much more dire injury.
In the first one to two days of these nondisruptive injuries there is an inflammatory response and between then and around seven days fibrous scar tissue begins to be laid down.
Immediately after the muscle is injured it is not able to produce more than 70% of maximum tension and this further declines to around 50%.
Tension production starts improving after that and by a week the muscle can produce at least 90% of normal tension. Normal tension would be that of the opposite non-injured muscle. However, even though the muscle can produce 90% of normal tension it’s tensile strength is somewhere around 75%. The implications of this should be obvious. The muscle is capable of exerting much more force than it can withstand. This ability of the muscle to return to an almost baseline state of force production is what leads those like Rippetoe to believe an injury is getting better because you work the area hard. The muscle is not healed or adapted or “stronger” just because force production has returned. What matters is whether the tensile strength has returned. The scar tissue that is laid down after an injury is nonpliable and easily damaged. It also creates adhesions that pull on the surrounding healthy tissue.
The only thing you can do about this type of thing is to avoid it, if possible. This means training smart. Add weight gradually. Add volume gradually. Increase your frequency gradually. Don’t look for DOMS as a training goal, as the continued seeking of soreness (like some people will tell you is necessary) can lead to cumulative trauma that becomes a strain when the muscle is tensioned enough. Keep in mind that I do not mean that avoid DOMS is correct either and sometimes, when hypertrophy is the goal, pursuing soreness can help you know whether you’ve really reached that hypertrophy zone, but this should be left to those with a lot of training history under their belt.
Remember, no injury is inevitable but injuries can sometimes be very difficult to avoid. Despite our best efforts, we will all sustain a strain or other injury at some point. But it is never inevitable, as all injuries CAN be avoided, even if we don’t always succeed in doing so.
Unnoticed injuries will be relatively minor ones. Once you do notice the injury, take proper steps to treat it. Major injuries in the gym you WILL notice, of course. And this actually brings us to another rule of thumb for muscle strains. The fact that you can use the strained muscle without a lot of pain, indeed, with no pain, points to a minor injury. Also, when there is pain, a minor injury will not tend to be painful when you aren’t using it, but only with movement or palpation. This kind of injury could easily be mistaken for an overuse injury, and, indeed, the distinctions between an acute and chronic injury can be vague. Do not sit around doing nothing for months on end waiting for muscle strains to heal up. But never return to previous activity just because you “can”. Taking the time to properly treat a small strain will make the difference between proper healing and continually re-occurring injury.
Be aware, when reading about both acute and chronic overuse injuries that explanations often suffer from the nominal fallacy, which assumes that naming the injuries, giving them a definition, provides an explanation.